Dietary modifications alone, such as clear liquids, are inadequate for colonoscopy but have proven benefit as an adjunct to other cleansing methods by decreasing the formation of solid residue. Clear liquids also help maintain adequate hydration during bowel preparation and

High dose senna has been used alone for bowel preparation and studies have shown comparable efficacy and better compliance. But the limiting factors were higher incidence of abdominal pain. Recently, the adjunctive use of low dose senna with PEG solutions has been demonstrated to improve the quality of bowel preparation36 and to reduce the amount of PEG-ELS required for effective bowel preparation. 41. This also reduces the abdominal pain reported with high dose senna. Bisacodyl (2-4 tablets of 5 mg each) and low-dose senna (36 mg, about 4 tablets of 8.6 mg Sennakot) are now commonly used as an adjunct to lowvolume PEG, achieving similar results to full-volume PEG. Based on the type of study, these

Magnesium citrate (1 bottle, about 300 cc) alone is also commonly used as an adjunct to low volume PEG solution with equivalent efficacy to high volume PEG solutions . In contrast, the routine use of non-absorbable carbohydrates such as mannitol and lactulose is not favored for bowel preparation since the hydrogen gas produced by bacterial fermentation of the non-absorbed carbohydrates increases the risk of explosion during electrosurgical

Metaclopramide (5- 10 mg), a dopamine antagonist gastroprokinetic that sensitizes tissues to the action of acetylcholine,is commonly used to address the nausea or vomiting associated

In patients who are intolerant to metaclopramide or are at high-risk for metaclopramide related side effects (such as in elderly), alternative anti-emetic agents such as promethazine

Simethicone (3 tablets of 80 mg each, total 240 mg dose), an anti-flatulent, anti-gas agent, is prescribed by many gastroenterologists in an attempt to reduce bubbles during colonoscopy and improve the visibility. It works by reducing the surface tension of air bubbles and causing the coalescence of small bubbles into larger ones that pass more easily with belching

bisacodyl or enemas and PEG or NaP solutions, is sparse.

are recommended with all bowel preparation regimens.

agents are given within 2 to 6 hours before starting of PEG solution. 37

**2.2 Adjuncts to bowel preparation**

**2.2.2 Stimulant laxatives**

**2.2.3 Hyperosmolar laxatives**

procedures. 38

**2.2.4 Antiemetic agents**

**2.2.5 Antifoaming agent**

or flatulence. 40

with bowel preparation agents. 39

(Phenergan) or ondansetron (Zofran) can be prescribed.

**2.2.1 Diet**

Enemas are sufficient for flexible sigmoidoscopies but when used alone do not permit adequate visualization of the proximal colon during colonoscopies. They are best used as adjuncts to other bowel preparation agents when patients present with poor distal colon preparation for colonoscopy. Enemas are also useful in washing out the distal segment of bowel in patients with a proximal stoma or a de-functioned distal colon. There have been studies comparing magnesium citrate with hypertonic enemas or oral bisacodyl as the bowel preparation for sigmoidoscopy over the use of hypertonic phosphate enemas alone. It was shown that there is no statistical difference between the quality of the three bowel preparations.42 In one study inadequately prepared patients during a 19-month period were successfully cleansed of their retained fecal contents with enemas, permitting satisfactory colonoscopic examinations. 21 Thus, for the management of patients who are sub-optimally prepared for colonoscopic examination because of retained fecal material the use of colonoscopic enema proves to be effective by avoiding the need for postponement of the procedure.43

The common types of enema are tap water, soap suds, Fleet (NaP), Fleet-Bisacodyl and mineral oil enemas

#### **2.2.7 Tap water enemas**

500 cc to 1L tap water enemas are commonly used for bowel cleansing on the evening prior or the morning of the procedure along with the dietary restrictions and cathartics, especially for flexible sigmoidoscopies. They usually work within 10–15 minutes but may need to be repeated one or two times to thoroughly cleanse the bowel in preparation for a bowel exam or bowel surgery. In general, tap water enemas are thought to be mild enemas and may be less effective than other forms of enemas. They have fewer side effects than NaP enemas though large or repeated amounts of tap water can still lead to electrolyte imbalances as the water is absorbed through the rectum and colon. Some people differentiate between high and low enemas. A high enema is usually administered at higher pressure and with larger volume (1,000 cc), and the patient is asked to change position several times in order for the fluid to flow up into the bowel. A low enema is administered at lower pressure, using about 500 cc of fluid.

#### **2.2.8 Soap suds enemas**

Soap suds enemas are thought to be more effective than plain tap water enemas. Soaps act as surfactant and make water a more aggressive solvent. This allows the bowel content to become more liquid. Soaps are also irritant to colon and lead to increased peristalsis and evacuation of bowel content. Some soaps are safer to use than others. In general, 2 to 3 drops of hand soap are added into an enema bag filled with 2 quarts of warm filtered water.

#### **2.2.9 NaP enemas**

Sodium Biphosphate (Fleet enemas) can be used for bowel cleansing before sigmoidoscopy. However this should be avoided in elderly and in those with renal failure because of the risk of developing hyperphosphatemia and subsequent hypocalcemia. In one study, one hundred and two consecutive patients were randomized: 56 to the Fleet enema group and 46 to the Picolax group (sodium picosulfate + magnesium citrate). It was found that Fleet enemas provided a significantly superior bowel preparation with 93% being judged as

Optimal Bowel Preparation for Colonoscopy 53

Our practice has been to place all patients on clear liquid diet and limit the bowel preparation to patients who have recently taken or actively taking iron supplements. On the other hand, some practices routinely use oral bowel preparation for capsule endoscopy not only to clean the colon, but also to promote capsule propulsion. For hospitalized patients who are unable to take bowel preparation easily, we recommend use of nasogastric tube to deliver PEG solutions before capsule endoscopy, whenever

Patients are usually prepared by taking clear liquids for 1 day before the procedure. Some practices (including ours) routinely use enemas to clear the pouch and distal small bowel

Bowel preparation is not needed for scoping through the ileostomy and in-fact may be relatively contraindicated is some cases due to the risk of increasing stoma output and causing dehydration. Bowel preparation for colostomy varies by site of colostomy and practice preference. For sigmoid colostomy, many physicians chose to give full bowel preparation. It is also preferable if the patients are on clear liquids for 1 day before the

Usually, enemas given within 2 hours of examination are adequate for bowel preparation for flexible sigmoidoscopy. Clear liquid diet for 1 day before procedure is optional. If patients are having diarrhea, then enemas are unnecessary. Many physicians chose not to give enemas to patients who have severe colitis, because of ongoing diarrhea and the

Decompressive colonoscopy is an exception when it comes to bowel preparation. Endoscopic decompression of the colon relieves acute pseudo-obstruction and megacolon in about 85% of patients but is associated with a perforation rate of about 2%. Because of the risk for colonic perforation, oral bowel preparation or enemas are avoided in these patients and decompressive colonoscopy is best done in unprepped bowel. Patients are mostly NPO

In our experience, many patients with ileal or colon strictures can successfully tolerate bowel preparation (including PEG). However, their symptoms need to be watched carefully and bowel preparation should be withheld if any significant nausea, vomiting or abdomen pain develops. Patients with high-grade strictures may not tolerate oral bowel preparation and may need enemas. Bowel preparation is contraindicated in patients with suspicion of

before pouchoscopies. Full bowel preparation is not required for pouchoscopies.

**2.3 Special situations 2.3.1 Capsule endoscopy**

indicated.

**2.3.2 Pouchoscopy**

**2.3.3 Ileostomy and colostomy**

**2.3.4 Flexible sigmoidoscopy**

in these settings.

bowel obstruction.

**2.3.6 Stricturing disease**

potential for increased perforation risk.

**2.3.5 Decompressive colonoscopy for megacolon**

procedure, especially if they have a colostomy.

adequate or better as opposed to 74% in the Picolax group. In addition Fleet enemas were associated with lesser adverse symptoms. It was thus concluded that Fleet enema is superior to Picolax in terms of bowel preparation for flexible sigmoidoscopy and the incidence of associated adverse symptoms.44

#### **2.2.10 Mineral oil enemas**

Mineral Oil is a lubricant laxative that works by slowing the absorption of water from the bowel which softens the stool. They are best reserved for refractory constipation. Possible side effects of mineral oil enema are:

	- Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); dizziness.
	- Failure to have a bowel movement within 6 to 8 hours after using Mineral Oil Enema; fainting; muscle cramps or pain; rectal bleeding; swelling, pain, or irritation; weakness

#### **2.2.11 Bisacodyl enemas**

A laxative which is used for treating constipation can also be used to empty the bowel before surgery and examinations such as X-Ray procedures using Barium enema. Bisacodyl can be used as tablet, suppository or as enema. It can also be combined with NaP and other enemas. However due precautions must be taken in the following cases.

The side effects that may be experienced during the use of Bisacodyl enema are:

#### **2.2.12 Nasogastric tubes**

Nasogastric tubes have been used to instill colonic preparations, especially for inpatients not able to drink PEG solutions or those who are unresponsive or mechanically ventilated. It can also be useful for rapid bowel cleansing

(within 2 to 3 hours) for patients with lower gastrointestinal bleeding. However, routine use of nasogastric tube solely for bowel preparation is discouraged as it can lead to severe complications, such as aspiration, in addition to trauma, during insertion. 44

#### **2.3 Special situations**

52 Endoscopic Procedures in Colon and Rectum

adequate or better as opposed to 74% in the Picolax group. In addition Fleet enemas were associated with lesser adverse symptoms. It was thus concluded that Fleet enema is superior to Picolax in terms of bowel preparation for flexible sigmoidoscopy and the incidence of

Mineral Oil is a lubricant laxative that works by slowing the absorption of water from the bowel which softens the stool. They are best reserved for refractory constipation. Possible

Mineral oil enema is not recommended for use in children younger than 2 years of age.

 Pregnancy and Breastfeeding: If the patient becomes pregnant, it is advised to discuss with their doctor the benefits and risks of using Mineral Oil Enema during pregnancy. It is unknown if Mineral Oil Enema is excreted in breast milk. Breastfeeding patients

Patients should seek medical attention right away if any of these SEVERE side effects

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest;

 Failure to have a bowel movement within 6 to 8 hours after using Mineral Oil Enema; fainting; muscle cramps or pain; rectal bleeding; swelling, pain, or

A laxative which is used for treating constipation can also be used to empty the bowel before surgery and examinations such as X-Ray procedures using Barium enema. Bisacodyl can be used as tablet, suppository or as enema. It can also be combined with NaP and other

Nasogastric tubes have been used to instill colonic preparations, especially for inpatients not able to drink PEG solutions or those who are unresponsive or mechanically ventilated. It can

(within 2 to 3 hours) for patients with lower gastrointestinal bleeding. However, routine use of nasogastric tube solely for bowel preparation is discouraged as it can lead to severe

complications, such as aspiration, in addition to trauma, during insertion. 44

1. If the patient is allergic to Bisacodyl, aspirin or any ingredients in these products. 2. In case the patient is pregnant, Breast-feeding or plans to become pregnant. The side effects that may be experienced during the use of Bisacodyl enema are:

Safety and effectiveness in this age group have not been confirmed.

must discuss the potential side effects with their doctor.

swelling of the mouth, face, lips, or tongue); dizziness.

enemas. However due precautions must be taken in the following cases.

irritation or burning in the rectum (from suppositories)

associated adverse symptoms.44

side effects of mineral oil enema are:

irritation; weakness

stomach and intestinal irritation

also be useful for rapid bowel cleansing

**2.2.11 Bisacodyl enemas**

 stomach cramps upset stomach diarrhea

**2.2.12 Nasogastric tubes**

faintness

Bloating, diarrhea, gas, nausea, stomach cramps.

**2.2.10 Mineral oil enemas**

occur:

#### **2.3.1 Capsule endoscopy**

Our practice has been to place all patients on clear liquid diet and limit the bowel preparation to patients who have recently taken or actively taking iron supplements. On the other hand, some practices routinely use oral bowel preparation for capsule endoscopy not only to clean the colon, but also to promote capsule propulsion. For hospitalized patients who are unable to take bowel preparation easily, we recommend use of nasogastric tube to deliver PEG solutions before capsule endoscopy, whenever indicated.

#### **2.3.2 Pouchoscopy**

Patients are usually prepared by taking clear liquids for 1 day before the procedure. Some practices (including ours) routinely use enemas to clear the pouch and distal small bowel before pouchoscopies. Full bowel preparation is not required for pouchoscopies.

#### **2.3.3 Ileostomy and colostomy**

Bowel preparation is not needed for scoping through the ileostomy and in-fact may be relatively contraindicated is some cases due to the risk of increasing stoma output and causing dehydration. Bowel preparation for colostomy varies by site of colostomy and practice preference. For sigmoid colostomy, many physicians chose to give full bowel preparation. It is also preferable if the patients are on clear liquids for 1 day before the procedure, especially if they have a colostomy.

#### **2.3.4 Flexible sigmoidoscopy**

Usually, enemas given within 2 hours of examination are adequate for bowel preparation for flexible sigmoidoscopy. Clear liquid diet for 1 day before procedure is optional. If patients are having diarrhea, then enemas are unnecessary. Many physicians chose not to give enemas to patients who have severe colitis, because of ongoing diarrhea and the potential for increased perforation risk.

#### **2.3.5 Decompressive colonoscopy for megacolon**

Decompressive colonoscopy is an exception when it comes to bowel preparation. Endoscopic decompression of the colon relieves acute pseudo-obstruction and megacolon in about 85% of patients but is associated with a perforation rate of about 2%. Because of the risk for colonic perforation, oral bowel preparation or enemas are avoided in these patients and decompressive colonoscopy is best done in unprepped bowel. Patients are mostly NPO in these settings.

#### **2.3.6 Stricturing disease**

In our experience, many patients with ileal or colon strictures can successfully tolerate bowel preparation (including PEG). However, their symptoms need to be watched carefully and bowel preparation should be withheld if any significant nausea, vomiting or abdomen pain develops. Patients with high-grade strictures may not tolerate oral bowel preparation and may need enemas. Bowel preparation is contraindicated in patients with suspicion of bowel obstruction.

Optimal Bowel Preparation for Colonoscopy 55

GoLYTELY in the evening before the procedure.

The colonoscopy generally takes 30-60 minutes

Educating patients about bowel preparation instructions is critical for ensuring adequate bowel preparation and helps reduce the risk of preparation related adverse events. Patients on blood thinners, or who are diabetics, need additional instructions from their treating physicians to find the best approach in continuing or withholding some of their medications

Follow the schedule in the table below for your bowel preparation. You may need to get to the toilet right away. You will have many bowel movements through the day. They will become very watery. The bowels are clear or clean when there is only pale yellow fluid

One of the key concepts to emphasize to patients is the need for adequate hydration during bowel preparation. Many patients mistakenly believe that taking 4 L of polyethylene glycol obviates the need for additional hydration, since they are already ingesting such a large volume of fluid. Given that bowel preparations induce diarrhea and, in some instances, nausea and decreased oral intake, all patients taking bowel preparations are at risk of dehydration.32 Hence, many safety issues associated with bowel preparation agents are

In general, patients should be advised to consume at least 64 oz (approximately 2 L) of clear fluid on the day before the colonoscopy. According to the American Society of

**2.4.1 General patient instruction sheet for split-dose PEG administration (with**

medications.

dehydration.

an enema may be needed

might take some time to wear off

Ask your doctor if you should take any of your medicines the morning of your test. If so, take with sips of water only.

If you have an afternoon appointment, begin drinking remaining GoLYTELY about 8 ounces every 10 minutes at 6:00 a.m. on the morning of the procedure, until finished at approximately 8:00 a.m. If your procedure is scheduled in early morning, you will need to get up in the night to finish the second half of GoLYTELY at least 2- 3 hours before the colonoscopy appointment or complete the entire

You should drink clear liquids at least 8 ounces of clear liquids every hour (no solids, alcohol or red colored drinks) until 2 hours before colonoscopy appointment. You may take your morning

If the eliminations do not become clear after the gallon is finished

You must have someone else drive you back home as sedation

procedure.You however should continue taking more liquids. After the colonoscopy, you are encouraged to drink fluids to prevent

You can resume the solid diet on the same day after the

**Morning of the**

**After the exam:**

**2.4 Patient Instructions**

during bowel preparation.

without flecks of stool.

**permission from Cleveland Clinic)**

**2.4.2 Key role of adequate hydration**

related to dehydration and its complications.

**exam:**

**physician know if you are**

be stopped as well

days prior to the exam.

Do not consume dairy products.

liquids until you go to bed.

 - Gatorade or other sports drinks (not red) - Kool-Aid or other flavored drinks (not red) - plain Jell-O or other gelatins (not red)

appointment. Do not take alcohol

to drink.

mix the solution until the before colonoscopy

Do not eat solid foods for 24 hours before colonoscopy

Do not take red-colored drinks, Jell-O or popsicles

containing iron)

**Please let your primary care physician or the prescribing**

inflammatory medications (motrin, advil, aleve etc) might need to

Have diabetes and take insulin. You may need to have your insulin

It is important to continue to take all other prescribed medications

Do not take bulk-forming agents (such as Metamucil, Citrucel etc.) Do not take iron-containing preparations (such as multi-vitamins

If you tend to be constipated, maintain clear, liquid diet for two

Arrange for a driver to take you back home after the procedure Purchase your prescription 2 - 5 days before colonoscopy. Do not

Do not add sugar or flavorings containing sugar to the solution. Refrigerating the solution, adding lemon juice or Crystal Lite and rapidly drinking 8 ounce portions (instead of sipping) may help. At 6:00 p.m. the evening before the procedure, begin drinking 8 ounces (240 ml, one cup) of the GoLYTELY every 15- 20 minutes until half of the solution is ingested. Continue drinking clear

It is essential to drink at least 8 ounces of clear liquids (1 cup) every hour while awake to avoid dehydration. Clear liquids include:

Some people do experience nausea when drinking so much liquid, so the physician may prescribe an anti-nausea medication in case it is needed. Golytely now comes in several flavors to make it easier

Taking blood thinners or antiplatelet agents such as warfarin(Coumadin), enoxaparin (Lovenox), fondaparinux (Arixtra), clopidogrel (Plavix), ticlopidine (Ticlid), anagrelide (Agrylin),cilostazol (Pletal), pentoxyphylline (trental), dipyridamole (Persantine) with aspirin (Aggrenox) Over-the-counter medications like aspirin or other anti-

adjusted the day before and the day of the procedure

**2 weeks before colonoscopy:**

**2-5 days before the**

**Evening of the exam:**

**procedure:**

#### **2.4 Patient Instructions**

Educating patients about bowel preparation instructions is critical for ensuring adequate bowel preparation and helps reduce the risk of preparation related adverse events. Patients on blood thinners, or who are diabetics, need additional instructions from their treating physicians to find the best approach in continuing or withholding some of their medications during bowel preparation.

#### **2.4.1 General patient instruction sheet for split-dose PEG administration (with permission from Cleveland Clinic)**

Follow the schedule in the table below for your bowel preparation. You may need to get to the toilet right away. You will have many bowel movements through the day. They will become very watery. The bowels are clear or clean when there is only pale yellow fluid without flecks of stool.

#### **2.4.2 Key role of adequate hydration**

One of the key concepts to emphasize to patients is the need for adequate hydration during bowel preparation. Many patients mistakenly believe that taking 4 L of polyethylene glycol obviates the need for additional hydration, since they are already ingesting such a large volume of fluid. Given that bowel preparations induce diarrhea and, in some instances, nausea and decreased oral intake, all patients taking bowel preparations are at risk of dehydration.32 Hence, many safety issues associated with bowel preparation agents are related to dehydration and its complications.

In general, patients should be advised to consume at least 64 oz (approximately 2 L) of clear fluid on the day before the colonoscopy. According to the American Society of

Optimal Bowel Preparation for Colonoscopy 57

[11] Clark LE, DiPalma JA, et al. Safety issues regarding colonic cleansing for diagnostic

[12] Nelson DB, Barkun AN, et al. Technology Status evaluation report. Colonoscopy

[13] Sharma VK, Steinberg EN, et al. Randomized, controlled study of pretreatment with

[15] Haapamäki MM, Lindström M, et al. Low-volume bowel preparation is inferior to standard 4 1 polyethylene glycol. Surg Endosc. 2011 Mar;25(3):897-901. [16] Coporaal S, KleibeukerJH, et al. Low-volume PEG plus ascorbic acid versus high-

[17] Marmo R, Rotondano G, et al. Effective bowel cleansing before colonoscopy: a

[18] Abut E, Guveli H, et al. Administration of olive oil followed by a low volume of

[19] Hjelkrem M, Stengel J, et al. MiraLAX Is Not as Effective as GoLytely in Bowel

[20] Enestyedt BK, Fennerty MB, et al. Randomised clinical trial: MiraLAX vs. Golytely - a

[21] Rex DK, Johnson DA, et al. American College of Gastroenterology Guidelines for Colorectal Cancer Screening 2008. Am J Gastroenterol 2009;104:739–750. [22] Rex DK, Imperiale TF, et al. Impact of bowel preparation on efficiency and cost of

[23] El Sayed AM, Kanafani ZA, et al. A randomized single-blind trial of whole vs. split-

[24] 24. Rostom A, Jolicoeur E, et al. A randomized prospective trial comparing different

[25] 25. Park JS, Sohn CI, et al. Quality and effect of single dose vs. split dose of polyethylene

[26] 26. Singal AK, Rosman AS, et al. The renal safety of bowel preparations for

[27] Russmann S, Lamerato L, et al. Risk of impaired renal function after colonoscopy: a

polyethylene glycol. Aliment Pharmacol Ther. 2008;27(1):41–47.

glycol. Am J Gastroenterol. 2007;102(12):2655–2663.

Cleansing Before Screening Colonoscopies. 2011;9(4):326-332.e1.

colonoscopy. Am J Gastroenterol 2002; 97:1696–1700.

glycol electrolyte lavage solution. Gastrointest Endosc.1997;46:541-3. [14] Adams WJ, Meagher AP, et al. Bisacodyl reduces the volume of PEG solution required

magnesium citrate on the quality of colonoscopy preparation with polyethylene

volume PEG as bowel preparation for colonoscopy. Scand J Gastroenterology 2010

randomized study of split-dosage versus non-split dosage regimens of highvolume versus low-volume polyethylene glycol solutions. Gastrointest

polyethylene glycol-electrolyte lavage solution improves patient satisfaction with right-side colonic cleansing over administration of the conventional volume of polyethylene glycol-electrolyte lavage solution for colonoscopy preparation.

controlled study of efficacy and patient tolerability in bowel preparation for

dose polyethylene glycol-electrolyte solution for colonoscopy preparation.

regimens of oral sodium phosphate and polyethylene glycol-based lavage solution in the preparation of patients for colonoscopy. Gastrointest Endosc 2006;64:544–552.

glycol bowel preparation for early-morning colonoscopy. Endoscopy. 2007

colonoscopy: a comparative study of oral sodium phosphate solution and

cohort study in patients receiving either oral sodium phosphate or polyethylene

and surgical procedures. Drug Saf. 2004;27:1235-42.

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Anesthesiologists, clear liquids can be safely ingested up until 2 hours before receiving anesthesia.33 Patients should also be advised to keep drinking extra fluids after the procedure is completed to reduce the risk of dehydration and its complications

#### **3. Conclusion**

Adequate bowel preparation is essential before colonoscopy. Choosing an agent can be confusing, especially with so many agents available in the market today. Polyethylene glycol solutions are safe and effective, and are the preferred agents for cleansing the colon. Sodium phosphate can still be prescribed for patients who cannot tolerate polyethylene glycol solutions, provided they are not at risk of electrolyte or fluid imbalances. Enemas, bisacodyl, and metoclopramide are mainly used as adjuncts to polyethylene glycol but by themselves are inadequate for cleansing the entire colon. In this chapter, we have reviewed the advantages and disadvantages of available regimens, provided bowel preparation instructions for patients and emphasized the need to consider split–dose regimens as well as the need for adequate hydration before and after colonoscopy.

#### **4. References**

Anesthesiologists, clear liquids can be safely ingested up until 2 hours before receiving anesthesia.33 Patients should also be advised to keep drinking extra fluids after the

Adequate bowel preparation is essential before colonoscopy. Choosing an agent can be confusing, especially with so many agents available in the market today. Polyethylene glycol solutions are safe and effective, and are the preferred agents for cleansing the colon. Sodium phosphate can still be prescribed for patients who cannot tolerate polyethylene glycol solutions, provided they are not at risk of electrolyte or fluid imbalances. Enemas, bisacodyl, and metoclopramide are mainly used as adjuncts to polyethylene glycol but by themselves are inadequate for cleansing the entire colon. In this chapter, we have reviewed the advantages and disadvantages of available regimens, provided bowel preparation instructions for patients and emphasized the need to consider split–dose regimens as well as

[1] Wexner SD, Beck DE, et al. A consensus document on bowel preparation before

[2] Harewood GC, Sharma VK, Et al. Impact of colonoscopy preparation quality on detection of suspected colonic neoplasia. Gastrointest Endosc. 2003 ;58(1):76-9. [3] Hendry PO, Jenkins JT, et al. The impact of poor bowel preparation on colonoscopy: a

[4] Golub RW, Kerner BA, et al. Colonic preparations-which one? A blinded, prospective,

[5] Marshall JB, Pineda JJ, et al. Prospective, randomized trial comparing sodium phosphate

[6] DiPalma JA, Marshall JB, et al. Comparison of a new sulfate-free polyethylene glycol

[7] DiPalma JA, Wolff BG, et al. Comparison of reduced volume versus four liters sulfate-

[8] Adams WJ, Meagher AP, et al Bisacodyl reduces the volume of polyethylene glycol solution required for bowel preparation. Dis Colon Rectum 1994; 37:229–233. [9] Sharma VK, Steinberg EN,et al. Randomized, controlled study of pretreatment with

glycol electrolyte lavage solution.Gastrointest Endosc 1997; 46:541–543. [10] Stratton S, Shelton P, et al. Feasibility of polyethylene glycol (PEG) 3350 (Miralax) for

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**3. Conclusion**

**4. References**

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**4**

*USA*

Rosalinda S. Hulse

*Jordan Hospital, Plymouth, MA*

**Monitoring During Colonoscopy**

Many individuals are still hesitant to undergo colonoscopy despite numerous advertisements and campaigns about it. A few years back, a famous TV personality named Katie Kouric, had her colonoscopy broadcasted through live television because she wanted the public to see that there's nothing scary or frightening about the procedure. Her husband died of colon cancer at a young age. Had he had a colonoscopy (Fig. 1), his cancer would have been diagnosed and treated early which could have saved or

The test remains an uncomfortable, frightening, and embarrassing and anxiety producing situation, especially for people undergoing it for the first time, which can then lead to delays in screening and treatment. Though endoscopic procedures can be performed and tolerated without sedation, studies have shown that "16% to 56% of such procedures are terminated because of pain".²² The goal of colonoscopy is to reach the cecum (the beginning of the large intestine). The scope is less likely to reach that destination, as it navigates the long and tortuous colon, without adequate sedation. Figure 2 shows the colon or large intestine and

**1. Introduction**

prolonged his life.

Fig. 1. Colonoscopy.

its location in the abdomen.

## **Monitoring During Colonoscopy**

### Rosalinda S. Hulse

*Jordan Hospital, Plymouth, MA USA*

#### **1. Introduction**

58 Endoscopic Procedures in Colon and Rectum

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[29] Hookey LC, Depew WT, et al. The safety profile of Oral sodium phosphate for colon cleansing before colonoscopy in adults. Gastrointestinal Endos. 2002;56:895-902. [30] Rex DK, Schwartz H, et al. Safety and colon-cleansing efficacy of a new residue-free formulation of sodium phosphate tablets. Am J Gastroenterol. 2006;101:2594-2604 [31] Aihara H, Saito S, et al. Comparison of two sodium phosphate tablet-based regimens

Am Soc Nephrol. 2005;16(11):3389–3396.

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polypectomy. Gastroenterology 1979; 77:1307–1310.

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27(6):728-33.

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colorectal cleanser. Drugs. 2009;69(1):123-36

phosphate bowel purgative: an underrecognized cause of chronic renal failure. J

and a polyethylene glycol regimen for colon cleansing prior to colonoscopy: a randomized prospective pilot study. Int J Colorectal Dis. 2009 Sep;24(9):1023-30. [32] Wruble L, Demicco M, et al. Residue-free sodium phosphate tablets (OsmoPrep) versus Visicol for colon cleansing Gastrointest Endosc. 2007 Apr;65(4):660-70. [33] Juluri R, Eckert G, et al. Meta-analysis: randomized controlled trials of 4-L polyethylene

glycol and sodium phosphate solution as bowel preparation for colonoscopy.

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colon cleansing by an oral electrolyte overload. Gastrointest Endosc 1978; 24:162–163.

randomized controlled trials of Simethicone for gastrointestinal endoscopic

balanced lavage solution (GoLytely) and sennoside. Gastroenterol Jpn 1992;

sigmoidoscopy: oral magnesium citrate combined with oral bisacodyl, one hypertonic phosphate enema, or two hypertonic phosphate enemas. Am J

[34] 34. Curran MP, Plosker GL, et al. Oral sodium phosphate solution: a review of its use as

[35] Hoy SM, Scott LJ, et al. Sodium picosulfate/magnesium citrate: a review of its use as a

[36] Varughese S, Kumar AR, et al. Morning-only one-gallon polyethylene glycol improves

[39] Rhodes JB, Engstrom J, Stone KF. Metoclopramide reduces the distress associated with

[40] Wu L, Cao Y, Liao C, Huang J, Gao F.Systematic review and meta-analysis of

[41] Iida Y, Miura S, et al. Bowel preparation for the total colonoscopy by 2000 ml of

[42] Fincher RK, Osgard EM, et al. Comparison of bowel preparations for flexible

[43] Sohn N, Weinstein MA, et al.Management of the poorly preparationared colonoscopy patient: colonoscopic colon enemas as a preparation for colonoscopy. 2008;51(4):462-6. [44] P.J Drew, M. Hughes, et al. The optimal bowel preparation for flexible sigmoidoscopy.

prospective study. Am J Gastroenetrology 2010 Nov;105(11):2368-74. [37] Ziegenhagen DJ, Zehnter E, et al. Addition of Senna improves colonoscopy preparation with lavage: a prospective randomized trial. Gastrointest Endosc 1991;37(5):547-9. [38] Bigard MA, Gaucher P, Lassalle C. Fatal colonic explosion during colonoscopic Many individuals are still hesitant to undergo colonoscopy despite numerous advertisements and campaigns about it. A few years back, a famous TV personality named Katie Kouric, had her colonoscopy broadcasted through live television because she wanted the public to see that there's nothing scary or frightening about the procedure. Her husband died of colon cancer at a young age. Had he had a colonoscopy (Fig. 1), his cancer would have been diagnosed and treated early which could have saved or prolonged his life.

#### Fig. 1. Colonoscopy.

The test remains an uncomfortable, frightening, and embarrassing and anxiety producing situation, especially for people undergoing it for the first time, which can then lead to delays in screening and treatment. Though endoscopic procedures can be performed and tolerated without sedation, studies have shown that "16% to 56% of such procedures are terminated because of pain".²² The goal of colonoscopy is to reach the cecum (the beginning of the large intestine). The scope is less likely to reach that destination, as it navigates the long and tortuous colon, without adequate sedation. Figure 2 shows the colon or large intestine and its location in the abdomen.

Monitoring During Colonoscopy 61

**2. Safety and efficacy of currently used sedation drugs for colonoscopy**

Sedation is defined as the calming of mental excitement or abatement of physiologic functions with the administration of a drug,³¹ i.e. a drug-induced depression of the individual's level of consciousness.⁴ As mentioned earlier, sedation is recommended in most endoscopic procedures to facilitate completion of the procedure, which in this case, would

Four levels characterize sedation: minimal or light (anxiolysis) sedation, moderate sedation (formerly known as conscious sedation), deep sedation, and general anesthesia.² The most commonly used in colonoscopy is moderate sedation, where the patient continues to respond purposefully to verbal commands, with or without light touch stimulation. He is spontaneously breathing on his own and may be supported with minimal amounts of oxygen via a nasal cannula or sometimes a mask may be necessary. In deeply sedated states, patients may not be roused easily, and respond only after repeated or painful stimuli. They may also not have spontaneous respirations (breathing on their own) requiring assistance to maintain a patent airway. General anesthesia is normally reserved for surgical procedures wherein patients do not respond to any form of stimulation, are completely immobile and support of his or her cardiovascular functioning is required.⁴ Table 1 shows summary of the various levels of sedation and analgesia. Adapted from the American Society of

Moderate anesthesia care (MAC) and/or moderate level of sedation (also formerly known as conscious sedation) is usually employed during colonoscopy. It allows for better patient cooperation and a quicker or shorter recovery time.²6 Individuals certified to administer the drugs and monitor the patient's response(s), such as a gastroenterologist, a registered nurse, a certified registered nurse anesthetist, or an anesthesiologist, can safely administer this.³² However, there are some differences between MAC and moderate sedation. During moderate sedation, a physician personally administers or supervises a nurse to administer the sedative and/or analgesic drug. These individuals are qualified and certified to administer the sedation drugs maintaining the level of sedation to a "moderate" or lesser degree. They continually monitor and assess the effects of these drugs and level of sedation the patient is in throughout the duration of the procedure, are competent to recognize changes especially when the individual goes into a deeper level than originally intended

Fig. 3. Confidence and satisfaction in colonoscopic procedures

Anesthesiologists Standards and Guidelines (2009).²

be colonoscopy.

Many countries around the world commonly perform colonoscopy without sedation. ¹² In Japan, though endoscopic procedures are routinely carried out without sedation, many Japanese are now choosing this to ease the discomfort.³² Only 2%-7% would prefer this option in the United States.²9

#### Fig. 2. The colon or large intestine

The challenge and goal of sedation in colonoscopy is to effectively facilitate the procedure while relieving anxiety, pain or discomfort, providing amnesia, and preserving cardiopulmonary function of the individual, with minimal cognitive impairment post procedure. This may delay the individual's discharge from the hospital. Sedation is now the standard of practice for endoscopic procedures in the U.S. and in many other countries. It is necessary to complete the procedure with ease and comfort.²6,¹9,²¹,²³,9,³²,³¹,³⁸ Currently used medications are: benzodiazepines (e.g., midazolam, diazepam), opioids (e.g., meperidine, sublimaze), and propofol. Ketamine and inhaled anesthetics (e.g. nitrous oxide) are rarely used because of their side effects and uneasiness of administration.²³,²² These drugs are used alone or in combination with another drug. Comparison studies have been done to determine which combination of drugs are better in minimizing cognitive impairment post procedure, but none have been found to be better than the other.²¹ The ideal amount of sedation for a patient undergoing colonoscopy has also not been established despite the many different techniques, medications and combinations thereof attempted.

This chapter will discuss the different types of moderate sedation given, who will be administering it, and how individuals are monitored during the procedure. The goal is to inform the public of the different methods of making one comfortable during colonoscopy. Emphasis will be given to the fact that this procedure is short and safe, and usually does not require administration of heavy-duty anesthetics or sedatives. Monitoring is done frequently with particular attention to the airway, breathing (using pulse oximetry and capnography) and circulation i.e., heart rate and blood pressure. Knowledge of the availability of these medications will make the individual feel confident that he or she will be comfortable and cared for during his or her colonoscopy.

Many countries around the world commonly perform colonoscopy without sedation. ¹² In Japan, though endoscopic procedures are routinely carried out without sedation, many Japanese are now choosing this to ease the discomfort.³² Only 2%-7% would prefer this

The challenge and goal of sedation in colonoscopy is to effectively facilitate the procedure while relieving anxiety, pain or discomfort, providing amnesia, and preserving cardiopulmonary function of the individual, with minimal cognitive impairment post procedure. This may delay the individual's discharge from the hospital. Sedation is now the standard of practice for endoscopic procedures in the U.S. and in many other countries. It is necessary to complete the procedure with ease and comfort.²6,¹9,²¹,²³,9,³²,³¹,³⁸ Currently used medications are: benzodiazepines (e.g., midazolam, diazepam), opioids (e.g., meperidine, sublimaze), and propofol. Ketamine and inhaled anesthetics (e.g. nitrous oxide) are rarely used because of their side effects and uneasiness of administration.²³,²² These drugs are used alone or in combination with another drug. Comparison studies have been done to determine which combination of drugs are better in minimizing cognitive impairment post procedure, but none have been found to be better than the other.²¹ The ideal amount of sedation for a patient undergoing colonoscopy has also not been established despite the many different techniques, medications and

This chapter will discuss the different types of moderate sedation given, who will be administering it, and how individuals are monitored during the procedure. The goal is to inform the public of the different methods of making one comfortable during colonoscopy. Emphasis will be given to the fact that this procedure is short and safe, and usually does not require administration of heavy-duty anesthetics or sedatives. Monitoring is done frequently with particular attention to the airway, breathing (using pulse oximetry and capnography) and circulation i.e., heart rate and blood pressure. Knowledge of the availability of these medications will make the individual feel confident that he or she will

option in the United States.²9

Fig. 2. The colon or large intestine

combinations thereof attempted.

be comfortable and cared for during his or her colonoscopy.

Fig. 3. Confidence and satisfaction in colonoscopic procedures

#### **2. Safety and efficacy of currently used sedation drugs for colonoscopy**

Sedation is defined as the calming of mental excitement or abatement of physiologic functions with the administration of a drug,³¹ i.e. a drug-induced depression of the individual's level of consciousness.⁴ As mentioned earlier, sedation is recommended in most endoscopic procedures to facilitate completion of the procedure, which in this case, would be colonoscopy.

Four levels characterize sedation: minimal or light (anxiolysis) sedation, moderate sedation (formerly known as conscious sedation), deep sedation, and general anesthesia.² The most commonly used in colonoscopy is moderate sedation, where the patient continues to respond purposefully to verbal commands, with or without light touch stimulation. He is spontaneously breathing on his own and may be supported with minimal amounts of oxygen via a nasal cannula or sometimes a mask may be necessary. In deeply sedated states, patients may not be roused easily, and respond only after repeated or painful stimuli. They may also not have spontaneous respirations (breathing on their own) requiring assistance to maintain a patent airway. General anesthesia is normally reserved for surgical procedures wherein patients do not respond to any form of stimulation, are completely immobile and support of his or her cardiovascular functioning is required.⁴ Table 1 shows summary of the various levels of sedation and analgesia. Adapted from the American Society of Anesthesiologists Standards and Guidelines (2009).²

Moderate anesthesia care (MAC) and/or moderate level of sedation (also formerly known as conscious sedation) is usually employed during colonoscopy. It allows for better patient cooperation and a quicker or shorter recovery time.²6 Individuals certified to administer the drugs and monitor the patient's response(s), such as a gastroenterologist, a registered nurse, a certified registered nurse anesthetist, or an anesthesiologist, can safely administer this.³² However, there are some differences between MAC and moderate sedation. During moderate sedation, a physician personally administers or supervises a nurse to administer the sedative and/or analgesic drug. These individuals are qualified and certified to administer the sedation drugs maintaining the level of sedation to a "moderate" or lesser degree. They continually monitor and assess the effects of these drugs and level of sedation the patient is in throughout the duration of the procedure, are competent to recognize changes especially when the individual goes into a deeper level than originally intended

Monitoring During Colonoscopy 63

anesthesiologist or certified registered nurse anesthetist, CRNA) are essential to manage the effects of general anesthesia as well as the patient's quick return to a lesser state of sedation. MAC also includes post-procedure responsibilities such as ensuring return to full consciousness, complete relief of pain, management of side effects or any adverse physiologic responses from the drugs administered during the procedure, as well as the

Since individuals vary in their responses to the sedation medication, and may be in different levels of sedation as well, while undergoing the same procedure, or may require different levels to complete the procedure; it is imperative that clinicians administering the sedatives/analgesics and monitoring their effects have the necessary skills and knowledge in recognizing complications associated with sedation/analgesia, and be able to rescue or resuscitate the individual whose sedation status is deeper than originally intended.⁴,³⁷ They must have also undergone a course or class and be certified in cardiopulmonary resuscitation (CPR) as well as in Advanced Cardiac Life Support (ACLS).²º,¹6,³⁷,³ In patients with significantly sedation-related risk factors, i.e., severe obstructive pulmonary disease, sleep apnea, potentially difficult airway, congestive heart failure, and coronary artery disease, the presence of an anesthesiologist is highly recommended. It is also recommended for patients who may require a deeper level of sedation to achieve adequate procedure result, such as individuals who are on high doses of psychotropic medications,

ASA II Patient has mild systemic disease which does not interfere with

ASA V The patient is moribund and is not expected to survive within 24

ASA VI The patient is declared brain-dead and his or her organs are being

<sup>E</sup>In addition to indicating the ASA status, a patient undergoing an emergency procedure is indicated by the suffix "E."

Table 2. Patient status classification according to the American Society of Anesthesiologists

Many studies have been performed regarding administration of these drugs during colonoscopy and were found to provide safe and effective sedation during the procedure, especially when titrated in small incremental doses. Though safe and effective, these drugs

hours, with or without the procedure

removed for donation purposes.

daily activities, such as high blood pressure that is under control

Patient has a moderate or severe systemic disease that does not inhibit or limit daily activities such as diabetes with some

Patient has a severe systemic disease that is a constant threat to life such as end-stage renal or liver failure, or congestive heart

diagnosis and treatment of some co-existing medical problems.²

benzodiazepines, alcohol, and narcotics.⁴,²²,³

ASA I A normal healthy patient

failure

systemic complications

**Class Description**

ASA III

ASA IV

(ASA)

and, are able to manage the consequences and adjust additional doses of the medication to maintain the desired level of consciousness.

Table 1. Summary of the various levels of sedation and analgesia. Adapted from the American Society of Anesthesiologists, Standards and Guidelines, 2009. ²

In moderate sedation, the provider assigned to observing and monitoring the patient as well as administering the sedation medications has other responsibilities and tasks that are interruptible and of short duration. The reverse is true for moderate anesthesia care or MAC, where the provider (usually an anesthesiologist or nurse anesthetist) is solely dedicated to the observation and monitoring of the patient and does not have any other procedure-related responsibilities. He must be prepared to convert to general anesthesia when the patient's cardiorespiratory status is compromised. It is an essential component of his initial assessment to evaluate the patient's actual or anticipated physiological problem that may compromise his cardiorespiratory status during the scheduled procedure. His ability to rescue a patient whose airway is compromised is a prerequisite to his ability to provide moderate anesthesia care. The administration of hypnotics, sedatives and analgesics, as well as other drugs commonly used for the induction and maintenance of general anesthesia is often, but not always, a part of monitored anesthesia care.⁴

Since sedation is a continuum, it is impossible to predict how an individual will respond to the drugs. Some patients may require only small amounts of sedation, but MAC is often indicated because even small doses of these medications could precipitate adverse physiologic responses that would require acute clinical interventions and resuscitation. If a patient's health status or condition, or medical/surgical history is likely to require sedation to a deeper level or even to a momentary period of general anesthesia, then MAC is the preferred method. Due to the strong possibility that a deep or deeper level of sedation may transition to general anesthesia, the skills and expertise of an anesthesia provider (e.g.

and, are able to manage the consequences and adjust additional doses of the medication to

**Moderate Sedation or Analgesia (Conscious Sedation)**

Purposeful response to verbal or tactile stimuli

No intervention required

maintained

In moderate sedation, the provider assigned to observing and monitoring the patient as well as administering the sedation medications has other responsibilities and tasks that are interruptible and of short duration. The reverse is true for moderate anesthesia care or MAC, where the provider (usually an anesthesiologist or nurse anesthetist) is solely dedicated to the observation and monitoring of the patient and does not have any other procedure-related responsibilities. He must be prepared to convert to general anesthesia when the patient's cardiorespiratory status is compromised. It is an essential component of his initial assessment to evaluate the patient's actual or anticipated physiological problem that may compromise his cardiorespiratory status during the scheduled procedure. His ability to rescue a patient whose airway is compromised is a prerequisite to his ability to provide moderate anesthesia care. The administration of hypnotics, sedatives and analgesics, as well as other drugs commonly used for the induction and maintenance of

Table 1. Summary of the various levels of sedation and analgesia. Adapted from the

general anesthesia is often, but not always, a part of monitored anesthesia care.⁴

Since sedation is a continuum, it is impossible to predict how an individual will respond to the drugs. Some patients may require only small amounts of sedation, but MAC is often indicated because even small doses of these medications could precipitate adverse physiologic responses that would require acute clinical interventions and resuscitation. If a patient's health status or condition, or medical/surgical history is likely to require sedation to a deeper level or even to a momentary period of general anesthesia, then MAC is the preferred method. Due to the strong possibility that a deep or deeper level of sedation may transition to general anesthesia, the skills and expertise of an anesthesia provider (e.g.

American Society of Anesthesiologists, Standards and Guidelines, 2009. ²

**Deep Sedation or Analgesia**

Purposeful response following repeated or painful stimuli

Intervention may be required

Maybe inadequate or compromised

Usually maintained

**General Anesthesia**

Unarousable even with repeated or painful stimuli

Intervention is often required

Frequently inadequate and is compromised

> Maybe impaired

maintain the desired level of consciousness.

**Airway** Unaffected

**Responsiveness**

**Spontaneous**

**Cardiovascular**

**Minimal or Light Sedation (Anxiolysis)**

Normal response to verbal stimuli

**Ventilation** Unaffected Adequate

**Function** Unaffected Usually

anesthesiologist or certified registered nurse anesthetist, CRNA) are essential to manage the effects of general anesthesia as well as the patient's quick return to a lesser state of sedation. MAC also includes post-procedure responsibilities such as ensuring return to full consciousness, complete relief of pain, management of side effects or any adverse physiologic responses from the drugs administered during the procedure, as well as the diagnosis and treatment of some co-existing medical problems.²

Since individuals vary in their responses to the sedation medication, and may be in different levels of sedation as well, while undergoing the same procedure, or may require different levels to complete the procedure; it is imperative that clinicians administering the sedatives/analgesics and monitoring their effects have the necessary skills and knowledge in recognizing complications associated with sedation/analgesia, and be able to rescue or resuscitate the individual whose sedation status is deeper than originally intended.⁴,³⁷ They must have also undergone a course or class and be certified in cardiopulmonary resuscitation (CPR) as well as in Advanced Cardiac Life Support (ACLS).²º,¹6,³⁷,³ In patients with significantly sedation-related risk factors, i.e., severe obstructive pulmonary disease, sleep apnea, potentially difficult airway, congestive heart failure, and coronary artery disease, the presence of an anesthesiologist is highly recommended. It is also recommended for patients who may require a deeper level of sedation to achieve adequate procedure result, such as individuals who are on high doses of psychotropic medications, benzodiazepines, alcohol, and narcotics.⁴,²²,³

Table 2. Patient status classification according to the American Society of Anesthesiologists (ASA)

Many studies have been performed regarding administration of these drugs during colonoscopy and were found to provide safe and effective sedation during the procedure, especially when titrated in small incremental doses. Though safe and effective, these drugs

Monitoring During Colonoscopy 65

unable to find an available designated driver and are unwilling to reschedule their appointment. Still some have stated that they have a lot of commitments and things to do that they cannot afford to skip a day to rest at home. In some rare instances, the individual went straight to work after his procedure. The type and level of monitoring should be tailored to each individual in these cases. Often, the individual is advised to bring a designated driver, in case he changes his mind and decides to receive sedation. Men, patients who are generally healthy and have no history of abdominal pain, individuals who are not anxious, and older patients may be better able to tolerate the colonoscopy without sedation. In situations like this, a smaller diameter endoscope (pediatric scope) is used and

A few weeks prior to the scheduled colonoscopy, the patient usually pays his endoscopist a visit to review his general state of health, medical and surgical histories, allergies, and regularly taken medications. Special instructions will be given to diabetics with regards to intake of their medications as well as diet. The appropriate bowel cleansing prep will be reviewed and instructions provided. The patient will also be informed that he will be receiving sedating medications to make the procedure more comfortable and tolerable. He is then advised to arrange for someone to drive him home because he will not be allowed to drive home, take the bus or taxi after the procedure due to the residual effects of the sedative; emphasizing the fact that these side effects do alter his reflexes and cognitive functioning. This usually wears off in about four to six hours; and, even after this time, the individual may still feel very tired and sleepy. Patients are discharged home and advised to take the day off and rest. They are normally allowed to eat light, non-spicy, and easily digestible foods to avoid nausea and vomiting which is often a side effect of sedatives and

The use of combination regimen as well as patient characteristics influence the safety and choice of sedative regimens for this procedure. Therefore, general data is collected from every patient, recorded in his medical record and reviewed by both the endoscopist and the personnel providing the sedating medication (s), shortly before the colonoscopy is performed. These include: name, age (determined by date-of-birth), sex, general condition of health (as outlined in the ASA classification, Table 2), daily medications taken, allergies, medical and surgical histories, adverse reactions to sedatives and anesthetics, and problems (if any) post procedure or surgery. The following historical events should also be obtained from the patient: any significant abnormalities of major organ or organ systems, snoring or sleep apnea (using CPAP or BiPap), time and type of last meal taken, use of illicit drugs, and alcohol and tobacco use. Regarding the "time and type of last meal taken," there are no absolute or ultimate guidelines regarding the stopping of oral intake prior to administration of sedatives. There are no supporting data showing a direct relationship between fasting time and risk of aspiration into the lungs. The ASA guidelines recommend that patients not have clear liquids two hours before the procedure and a light meal six hours before administration of any sedating medication. This would allow sufficient time for the stomach to adequately empty.⁴ According to the American College of Emergency Physicians, "recent food intake is not contraindicated for administering procedural sedation and analgesia, but

should be considered in choosing the timing and target of sedation".⁸

is better tolerated.

opioids.

**5. Preprocedure assessment and monitoring**

do carry potential problems or concerns that include cardiopulmonary events, such as hypotension, airway obstruction, hypoxia/hypoxemia, aspiration, apnea, arrhythmia, vasovagal episodes, and though uncommon, serious morbidity and death can also occur.²⁴,¹⁵,¹6 A review of data from the American Society for Gastrointestinal Endoscopy's (ASGE) computer-based management system of 21,000 GI endoscopies in 1988 using Versed (Midazolam) and Valium (Diazepam) revealed the following: Overall complication rate was 13.5 events per 1000 procedures and serious cardiopulmonary events were 5.4 per 1000. Death occurred in 0.3 per 1000.⁵ Another study evaluating the safety of the combination of meperidine (Demerol) with either midazolam (Versed) or diazepam (Valium) revealed no deaths.6 Results from two other studies showed a considerably lower incidence of cardiopulmonary complications using propofol as compared with the use of benzodiazepines during routine endoscopic procedure.³⁸,²⁵,²⁸ Because of these potential complications, endoscopy suites are equipped with the tools necessary to rescue the patient. These include: a suction machine, oxygen outlet or tank, a code cart with a defibrillator, a bag-valve mask, oral and nasal airways, a nasogastric tube, materials for respiratory intubation, and drugs required for cardiorespiratory resuscitation.²º

### **3. Economics of sedation in endoscopy**

In the past, gastroenterologists have routinely administered the sedating agents to their patients as part of the colonoscopy service. However, in recent years, many endoscopists are employing the services of an anesthesiologist or a certified registered nurse anesthetist (CRNA) to administer the sedation. The influencing factors being, the increased use of propofol during this procedure, effective marketing by anesthesiologists, and by a decrease in reimbursements by insurers.⁴,³⁵

The approach of individual countries towards administration of sedatives and analgesics during colonoscopy varies widely due to differences in health insurance reimbursements and budget restraints.⁴¹,²² In the United States, Medicare reimbursements for use of an anesthesiologist during colonoscopy are not uniform across the nation. Some health insurers also question the separate billing of anesthesia service when generally; reimbursement fee for the colonoscopy includes administration of sedation under the supervision of the gastroenterologist.¹

Ideally, an anesthesiologist is present in all cases of colonoscopy to optimize sedation and analgesia. However, his presence during this short procedure for individuals who are at average-risk for developing sedation-related complications is debatable and not costeffective.¹ Normally, these patients are able to maintain their airway with minimal or no support so that the skills of an anesthesiologist is not necessary. Many studies have been done exploring the use of a registered nurse administering propofol and have found safety levels equivalent to those administered with benzodiazepines and narcotics.³²,³³,³º,³6

#### **4. Colonoscopy without sedation**

In some instances, few selected patients opt to undergo their colonoscopy without sedation. In the US, a survey found that only 2% to 7% of individuals were willing to do their colonoscopies without sedation.²9 Review of literature found no randomized control trials done to compare sedation versus no sedation during colonoscopy. Many argue that they want to watch the procedure and are fascinated by what's inside the human body. Some are

do carry potential problems or concerns that include cardiopulmonary events, such as hypotension, airway obstruction, hypoxia/hypoxemia, aspiration, apnea, arrhythmia, vasovagal episodes, and though uncommon, serious morbidity and death can also occur.²⁴,¹⁵,¹6 A review of data from the American Society for Gastrointestinal Endoscopy's (ASGE) computer-based management system of 21,000 GI endoscopies in 1988 using Versed (Midazolam) and Valium (Diazepam) revealed the following: Overall complication rate was 13.5 events per 1000 procedures and serious cardiopulmonary events were 5.4 per 1000. Death occurred in 0.3 per 1000.⁵ Another study evaluating the safety of the combination of meperidine (Demerol) with either midazolam (Versed) or diazepam (Valium) revealed no deaths.6 Results from two other studies showed a considerably lower incidence of cardiopulmonary complications using propofol as compared with the use of benzodiazepines during routine endoscopic procedure.³⁸,²⁵,²⁸ Because of these potential complications, endoscopy suites are equipped with the tools necessary to rescue the patient. These include: a suction machine, oxygen outlet or tank, a code cart with a defibrillator, a bag-valve mask, oral and nasal airways, a nasogastric tube, materials for respiratory

In the past, gastroenterologists have routinely administered the sedating agents to their patients as part of the colonoscopy service. However, in recent years, many endoscopists are employing the services of an anesthesiologist or a certified registered nurse anesthetist (CRNA) to administer the sedation. The influencing factors being, the increased use of propofol during this procedure, effective marketing by anesthesiologists, and by a decrease

The approach of individual countries towards administration of sedatives and analgesics during colonoscopy varies widely due to differences in health insurance reimbursements and budget restraints.⁴¹,²² In the United States, Medicare reimbursements for use of an anesthesiologist during colonoscopy are not uniform across the nation. Some health insurers also question the separate billing of anesthesia service when generally; reimbursement fee for the colonoscopy includes administration of sedation under the supervision of the

Ideally, an anesthesiologist is present in all cases of colonoscopy to optimize sedation and analgesia. However, his presence during this short procedure for individuals who are at average-risk for developing sedation-related complications is debatable and not costeffective.¹ Normally, these patients are able to maintain their airway with minimal or no support so that the skills of an anesthesiologist is not necessary. Many studies have been done exploring the use of a registered nurse administering propofol and have found safety

In some instances, few selected patients opt to undergo their colonoscopy without sedation. In the US, a survey found that only 2% to 7% of individuals were willing to do their colonoscopies without sedation.²9 Review of literature found no randomized control trials done to compare sedation versus no sedation during colonoscopy. Many argue that they want to watch the procedure and are fascinated by what's inside the human body. Some are

levels equivalent to those administered with benzodiazepines and narcotics.³²,³³,³º,³6

intubation, and drugs required for cardiorespiratory resuscitation.²º

**3. Economics of sedation in endoscopy**

in reimbursements by insurers.⁴,³⁵

**4. Colonoscopy without sedation**

gastroenterologist.¹

unable to find an available designated driver and are unwilling to reschedule their appointment. Still some have stated that they have a lot of commitments and things to do that they cannot afford to skip a day to rest at home. In some rare instances, the individual went straight to work after his procedure. The type and level of monitoring should be tailored to each individual in these cases. Often, the individual is advised to bring a designated driver, in case he changes his mind and decides to receive sedation. Men, patients who are generally healthy and have no history of abdominal pain, individuals who are not anxious, and older patients may be better able to tolerate the colonoscopy without sedation. In situations like this, a smaller diameter endoscope (pediatric scope) is used and is better tolerated.

#### **5. Preprocedure assessment and monitoring**

A few weeks prior to the scheduled colonoscopy, the patient usually pays his endoscopist a visit to review his general state of health, medical and surgical histories, allergies, and regularly taken medications. Special instructions will be given to diabetics with regards to intake of their medications as well as diet. The appropriate bowel cleansing prep will be reviewed and instructions provided. The patient will also be informed that he will be receiving sedating medications to make the procedure more comfortable and tolerable. He is then advised to arrange for someone to drive him home because he will not be allowed to drive home, take the bus or taxi after the procedure due to the residual effects of the sedative; emphasizing the fact that these side effects do alter his reflexes and cognitive functioning. This usually wears off in about four to six hours; and, even after this time, the individual may still feel very tired and sleepy. Patients are discharged home and advised to take the day off and rest. They are normally allowed to eat light, non-spicy, and easily digestible foods to avoid nausea and vomiting which is often a side effect of sedatives and opioids.

The use of combination regimen as well as patient characteristics influence the safety and choice of sedative regimens for this procedure. Therefore, general data is collected from every patient, recorded in his medical record and reviewed by both the endoscopist and the personnel providing the sedating medication (s), shortly before the colonoscopy is performed. These include: name, age (determined by date-of-birth), sex, general condition of health (as outlined in the ASA classification, Table 2), daily medications taken, allergies, medical and surgical histories, adverse reactions to sedatives and anesthetics, and problems (if any) post procedure or surgery. The following historical events should also be obtained from the patient: any significant abnormalities of major organ or organ systems, snoring or sleep apnea (using CPAP or BiPap), time and type of last meal taken, use of illicit drugs, and alcohol and tobacco use. Regarding the "time and type of last meal taken," there are no absolute or ultimate guidelines regarding the stopping of oral intake prior to administration of sedatives. There are no supporting data showing a direct relationship between fasting time and risk of aspiration into the lungs. The ASA guidelines recommend that patients not have clear liquids two hours before the procedure and a light meal six hours before administration of any sedating medication. This would allow sufficient time for the stomach to adequately empty.⁴ According to the American College of Emergency Physicians, "recent food intake is not contraindicated for administering procedural sedation and analgesia, but should be considered in choosing the timing and target of sedation".⁸

Monitoring During Colonoscopy 67

procedure with the patient. He will then sign the consent form allowing the endoscopist to perform the procedure and to be given sedating medications (if agreeing to sedation). The anticipated level of sedation should be congruent with the expected level of sedation by the individual as much as possible. The endoscopist will also review the colonoscopy procedure, the benefits, risks and complications to patients who are not receiving sedation. Preparation is the same as for sedation in the event that an emergency arises or the patient

requests medication during the procedure.

Fig. 4. Mallampati classification of airway management.

**6. Sedation and monitoring during colonoscopy**

non-anesthesiologists.¹¹,³²,¹⁵,²9

According to the recommendations outlined by The Joint Commission and the Association of Anesthesiologists, hospital-based endoscopy suites consists of the following personnel: a physician endoscopist, an assisting nurse, and an additional nurse solely administering sedatives and monitoring the patient.¹⁴ However, with the advent and increased use of propofol, there has been a demand for the presence of an anesthesiologist or certified registered nurse anesthesiologist. This is partly due to the widespread perception that the drug carries major complication risks and statements emphasized by the information on the package insert of the drug itself, recommending that only personnel trained in the administration of general anesthesia administer this drug. The ASA guidelines also outlined numerous precautions regarding the administration of propofol thereby, increasing fears of non-anesthetists. It is also the perception that administration of benzodiazepines and opiates only induce moderate level of sedation and that propofol brings the patient into a deep level sedation.²º Several studies though have proved that propofol can be safely administered by

Physical examination of the individual is obtained and recorded. These include, initial vital signs (temperature, heart rate, blood pressure, respiratory rate, and oxygen saturation), level of consciousness, examination of heart and lungs, and airway anatomy (using the Mallampati classification, Figure 4). The last one is important in situations where the individual may need resuscitative assistance such as: 1) individuals with a history of snoring, stridor, or sleep apnea and is using a CPAP or BiPAP machine, 2) neck abnormalities involving the neck and facial features (e.g. obese persons), short neck, limited neck extension, neck mass, cervical spine disease or trauma to the neck, tracheal deviation, advanced rheumatoid arthritis, decreased hyoid-mental distance (<3cm in adults), 3) abnormalities of the mouth such as protruding incisors, small opening ( <3cm n adults), high arched palate, hypertrophy of the tonsils, nonvisible uvula (see class 4 of the Mallampati classification, Figure 4), edentulous, loose or capped teeth, macroglossia, 4) history of problems with sedation and anesthetics, 5) dysmorphic facial features such as trisomy and Pierre-Robin syndrome, and 6) jaw abnormalities such as trismus, significant malocclusion, micrognathia, and retrognathia. The ASA Task Force guideline states "that the presence of one or more sedation-related risk factors coupled with the potential for deep sedation will increase the likelihood of adverse sedation-related events." Consultation with someone trained in managing these complex situations, usually an anesthesiologist or a certified registered nurse anesthetist should be considered.⁴ The presence of an anesthesiologist is also highly recommended for the following situations:

A Modified Aldrete score is also assigned (see post procedure monitoring). An intravenous access is established because sedation drugs are normally given intravenously. Fluids may or may not be routinely given depending on the institution's procedural policies and regulations. For female patients, it is necessary to mention the possibility of being pregnant or is pregnant. If in doubt, a pregnancy test may be performed. Lactating mothers should also mention if they are breastfeeding as most of the medication is excreted in breast milk.

Shortly before the procedure starts, the provider of the sedating medications will discuss with the patient the type of sedating medications to be given; its benefits, risks and complications, limitations and other alternatives. The endoscopist will also review the

Physical examination of the individual is obtained and recorded. These include, initial vital signs (temperature, heart rate, blood pressure, respiratory rate, and oxygen saturation), level of consciousness, examination of heart and lungs, and airway anatomy (using the Mallampati classification, Figure 4). The last one is important in situations where the individual may need resuscitative assistance such as: 1) individuals with a history of snoring, stridor, or sleep apnea and is using a CPAP or BiPAP machine, 2) neck abnormalities involving the neck and facial features (e.g. obese persons), short neck, limited neck extension, neck mass, cervical spine disease or trauma to the neck, tracheal deviation, advanced rheumatoid arthritis, decreased hyoid-mental distance (<3cm in adults), 3) abnormalities of the mouth such as protruding incisors, small opening ( <3cm n adults), high arched palate, hypertrophy of the tonsils, nonvisible uvula (see class 4 of the Mallampati classification, Figure 4), edentulous, loose or capped teeth, macroglossia, 4) history of problems with sedation and anesthetics, 5) dysmorphic facial features such as trisomy and Pierre-Robin syndrome, and 6) jaw abnormalities such as trismus, significant malocclusion, micrognathia, and retrognathia. The ASA Task Force guideline states "that the presence of one or more sedation-related risk factors coupled with the potential for deep sedation will increase the likelihood of adverse sedation-related events." Consultation with someone trained in managing these complex situations, usually an anesthesiologist or a certified registered nurse anesthetist should be considered.⁴ The presence of an

anesthesiologist is also highly recommended for the following situations:

continuous oxygen therapy or using CPAP or BiPAP machines Individuals with difficult airways (such as those described above)

Unavailability of a trained practitioner to administer moderate sedation

Extremely obese individuals

The individual is pregnant

safety and comfort

Adverse reactions to sedatives

medication is excreted in breast milk.

ASA status classification of Class III, IV, and V

Increased risk of pulmonary aspiration

and airway will be compromised

Inadequate response to moderate sedation

 Significantly compromised individuals such as those with congestive heart failure, coronary artery disease, and severe obstructive pulmonary disease (COPD) on

If it appears that sedation (even with small doses) will make the patient unresponsive

General anesthesia is necessary to complete the procedure while maintaining patient

A Modified Aldrete score is also assigned (see post procedure monitoring). An intravenous access is established because sedation drugs are normally given intravenously. Fluids may or may not be routinely given depending on the institution's procedural policies and regulations. For female patients, it is necessary to mention the possibility of being pregnant or is pregnant. If in doubt, a pregnancy test may be performed. Lactating mothers should also mention if they are breastfeeding as most of the

Shortly before the procedure starts, the provider of the sedating medications will discuss with the patient the type of sedating medications to be given; its benefits, risks and complications, limitations and other alternatives. The endoscopist will also review the

Anticipated intolerance of standard sedation drugs (e.g. alcohol or substance abuse)

procedure with the patient. He will then sign the consent form allowing the endoscopist to perform the procedure and to be given sedating medications (if agreeing to sedation). The anticipated level of sedation should be congruent with the expected level of sedation by the individual as much as possible. The endoscopist will also review the colonoscopy procedure, the benefits, risks and complications to patients who are not receiving sedation. Preparation is the same as for sedation in the event that an emergency arises or the patient requests medication during the procedure.

Fig. 4. Mallampati classification of airway management.

#### **6. Sedation and monitoring during colonoscopy**

According to the recommendations outlined by The Joint Commission and the Association of Anesthesiologists, hospital-based endoscopy suites consists of the following personnel: a physician endoscopist, an assisting nurse, and an additional nurse solely administering sedatives and monitoring the patient.¹⁴ However, with the advent and increased use of propofol, there has been a demand for the presence of an anesthesiologist or certified registered nurse anesthesiologist. This is partly due to the widespread perception that the drug carries major complication risks and statements emphasized by the information on the package insert of the drug itself, recommending that only personnel trained in the administration of general anesthesia administer this drug. The ASA guidelines also outlined numerous precautions regarding the administration of propofol thereby, increasing fears of non-anesthetists. It is also the perception that administration of benzodiazepines and opiates only induce moderate level of sedation and that propofol brings the patient into a deep level sedation.²º Several studies though have proved that propofol can be safely administered by non-anesthesiologists.¹¹,³²,¹⁵,²9

Monitoring During Colonoscopy 69

hypotensive (ASGE, 2008). Should the patient's condition get compromised or deteriorate at any given time during the procedure, the colonoscopy is halted and resuscitative measures are instituted. He may need to be transferred to the Critical Care Unit or the Emergency

Upon completion of the colonoscopy, the patient is kept in the room and monitored for a few more minutes until he is rousable and able to maintain his airway independently. Shortly thereafter, he is disconnected from all the monitoring equipment and brought to the recovery or discharge area to allow the effects of the sedatives to wear off. Here, the same parameters monitored during the procedure are monitored and recorded every 10-15 minutes for about half-an-hour to an hour, without the continuous cardiac monitoring (ECG) (unless warranted) and the carbon dioxide monitoring, until the patient is at or close to his or her baseline cognitive functioning level as possible, and is ready for discharge to home. Blood sugar levels of diabetics will also be checked and intervention given as

At this time, the endoscopist will come to discuss his findings during the procedure, any interventions done (i.e. biopsies taken), and discharge and follow-up instructions will be given. The patient's designated driver is encouraged to be present because he (the patient) may not remember what the endoscopist has said as a result of the amnesic properties of the sedatives, especially with benzodiazepines (not so with propofol), unless the patient requests otherwise. The patient is discharged when he or she has met discharge criteria as outlined by the Modified Aldrete or Aldrete and Kroulik scoring system (Tables 3 and 3.a) or whichever discharge scoring system the institution is using and has returned to his

Ideally, the recovery or discharge area should allow rapid recovery of the sedated individual, with minimal or without residual physiologic, cognitive or psychomotor impairments. Several discharge criteria have been formulated to facilitate and guide clinicians to objectively asses the clinical status of the sedated patient and be able to discharge him home. The most commonly used is the Modified Aldrete or Aldrete and Kroulik scoring systems (Table 3 and 3.a).³9 The preferred method is the Modified Aldrete scoring system as most institutions do not use arterial pressure monitoring for endoscopy procedures, especially in an outpatient setting. This scoring is also used pre-, inta and post procedure. During the procedure, if the patient is maintained at the moderate sedation level, his score should be a 9 or a 10 or whatever his baseline score was at the start. Over sedation is defined by a score of less than 9 and corrective action should be initiated. All post sedation patients should have their vital signs back to within 10% of their baseline score or be admitted to the hospital for further evaluation especially if corrective/resuscitative

Post anesthesia discharge scoring system (PADSS) has been developed for post-anesthesia care units in Canada. This allows the health care providers to monitor the patient's readiness to be discharged home. The average length of time the sedated patient stays in the discharge or recovery area is half-an-hour to an-hour depending on the kind and amount of sedation drugs received during the procedure. Patients who receive propofol generally recover quicker and are discharged home in a much shorter time than those who receive benzodiazepines or in combination thereof.²º Prompt and safe discharge of the patients

baseline (or close to it) level of cognitive and physiological functioning as possible.

actions have failed to improve his score or condition.

Department for further management.

**6.1 Post procedure monitoring**

necessary.

Only 7.7% of gastroenterologists in the US administer propofol themselves without the assistance or presence of an anesthesiologist or nurse anesthetist (CRNA), and 68% have expressed interest in incorporating it in their practice given proper training and adequately trained staff.9 The reason for the reluctancy among endoscopists to administer propofol themselves, are medico legal implications of the off-label use of propofol, the potential risks and complications, local institutional policy, and state regulatory restrictions.⁴ Hence, propofol is usually administered by an anesthesiologist (or by a certified registered nurse anesthetist [CRNA]) which is often not cost-effective in ambulatory gastrointestinal (GI) suites .¹² In some countries, like Switzerland, 34% of gastroenterologists polled administer propofol themselves.¹⁵

During the procedure, the patient is hooked up to a monitor that measures and displays the heart rate, blood pressure, and oxygen saturation (Figure 5) and in some cases, carbon dioxide levels (capnography). Some have also used transcutaneous carbon dioxide measurement or bispectral index monitoring (BIS). The latter is a quantitative assessment of cortical activity that has been used to monitor sedation and adjust sedation levels (Kissin, I., 2000). These are monitored by a licensed personnel (usually the person providing the sedation) every 3-5minutes during the procedure and with each incremental dose of the sedative. Monitoring may detect changes in the individual's blood pressure, heart rate, cardiac electrical activity, ventilatory, and neurologic status that might signal a clinically significant compromise of the patient's health status or that the patient has progressed to a deeper level of sedation than originally intended. Oxygen is usually given as an adjunct via a nasal cannula or mask as all of the sedation agents depress the respiratory system. The ASA guidelines recommend that patients receiving sedation medications receive continuous electrocardiogram (ECG) monitoring, especially if they have significant cardiovascular disease or arrhythmias.²º Parameters outlined in the Modified Aldrete scoring system, which includes the above mentioned items plus activity and consciousness are also monitored and recorded.

Fig. 5. Sample of monitoring equipment used

In most institutions, an intravenous access is started and IV fluids are given prior and during the procedure. This helps hydrate the patient, provide an avenue for the administration of sedating drugs, and as a rescue means should the patient become

Only 7.7% of gastroenterologists in the US administer propofol themselves without the assistance or presence of an anesthesiologist or nurse anesthetist (CRNA), and 68% have expressed interest in incorporating it in their practice given proper training and adequately trained staff.9 The reason for the reluctancy among endoscopists to administer propofol themselves, are medico legal implications of the off-label use of propofol, the potential risks and complications, local institutional policy, and state regulatory restrictions.⁴ Hence, propofol is usually administered by an anesthesiologist (or by a certified registered nurse anesthetist [CRNA]) which is often not cost-effective in ambulatory gastrointestinal (GI) suites .¹² In some countries, like Switzerland, 34% of gastroenterologists polled administer

During the procedure, the patient is hooked up to a monitor that measures and displays the heart rate, blood pressure, and oxygen saturation (Figure 5) and in some cases, carbon dioxide levels (capnography). Some have also used transcutaneous carbon dioxide measurement or bispectral index monitoring (BIS). The latter is a quantitative assessment of cortical activity that has been used to monitor sedation and adjust sedation levels (Kissin, I., 2000). These are monitored by a licensed personnel (usually the person providing the sedation) every 3-5minutes during the procedure and with each incremental dose of the sedative. Monitoring may detect changes in the individual's blood pressure, heart rate, cardiac electrical activity, ventilatory, and neurologic status that might signal a clinically significant compromise of the patient's health status or that the patient has progressed to a deeper level of sedation than originally intended. Oxygen is usually given as an adjunct via a nasal cannula or mask as all of the sedation agents depress the respiratory system. The ASA guidelines recommend that patients receiving sedation medications receive continuous electrocardiogram (ECG) monitoring, especially if they have significant cardiovascular disease or arrhythmias.²º Parameters outlined in the Modified Aldrete scoring system, which includes the above mentioned items plus activity and consciousness are also

In most institutions, an intravenous access is started and IV fluids are given prior and during the procedure. This helps hydrate the patient, provide an avenue for the administration of sedating drugs, and as a rescue means should the patient become

propofol themselves.¹⁵

monitored and recorded.

Fig. 5. Sample of monitoring equipment used

hypotensive (ASGE, 2008). Should the patient's condition get compromised or deteriorate at any given time during the procedure, the colonoscopy is halted and resuscitative measures are instituted. He may need to be transferred to the Critical Care Unit or the Emergency Department for further management.

#### **6.1 Post procedure monitoring**

Upon completion of the colonoscopy, the patient is kept in the room and monitored for a few more minutes until he is rousable and able to maintain his airway independently. Shortly thereafter, he is disconnected from all the monitoring equipment and brought to the recovery or discharge area to allow the effects of the sedatives to wear off. Here, the same parameters monitored during the procedure are monitored and recorded every 10-15 minutes for about half-an-hour to an hour, without the continuous cardiac monitoring (ECG) (unless warranted) and the carbon dioxide monitoring, until the patient is at or close to his or her baseline cognitive functioning level as possible, and is ready for discharge to home. Blood sugar levels of diabetics will also be checked and intervention given as necessary.

At this time, the endoscopist will come to discuss his findings during the procedure, any interventions done (i.e. biopsies taken), and discharge and follow-up instructions will be given. The patient's designated driver is encouraged to be present because he (the patient) may not remember what the endoscopist has said as a result of the amnesic properties of the sedatives, especially with benzodiazepines (not so with propofol), unless the patient requests otherwise. The patient is discharged when he or she has met discharge criteria as outlined by the Modified Aldrete or Aldrete and Kroulik scoring system (Tables 3 and 3.a) or whichever discharge scoring system the institution is using and has returned to his baseline (or close to it) level of cognitive and physiological functioning as possible.

Ideally, the recovery or discharge area should allow rapid recovery of the sedated individual, with minimal or without residual physiologic, cognitive or psychomotor impairments. Several discharge criteria have been formulated to facilitate and guide clinicians to objectively asses the clinical status of the sedated patient and be able to discharge him home. The most commonly used is the Modified Aldrete or Aldrete and Kroulik scoring systems (Table 3 and 3.a).³9 The preferred method is the Modified Aldrete scoring system as most institutions do not use arterial pressure monitoring for endoscopy procedures, especially in an outpatient setting. This scoring is also used pre-, inta and post procedure. During the procedure, if the patient is maintained at the moderate sedation level, his score should be a 9 or a 10 or whatever his baseline score was at the start. Over sedation is defined by a score of less than 9 and corrective action should be initiated. All post sedation patients should have their vital signs back to within 10% of their baseline score or be admitted to the hospital for further evaluation especially if corrective/resuscitative actions have failed to improve his score or condition.

Post anesthesia discharge scoring system (PADSS) has been developed for post-anesthesia care units in Canada. This allows the health care providers to monitor the patient's readiness to be discharged home. The average length of time the sedated patient stays in the discharge or recovery area is half-an-hour to an-hour depending on the kind and amount of sedation drugs received during the procedure. Patients who receive propofol generally recover quicker and are discharged home in a much shorter time than those who receive benzodiazepines or in combination thereof.²º Prompt and safe discharge of the patients

Monitoring During Colonoscopy 71

Colonoscopy procedures are usually done under moderate level of sedation or moderate anesthesia care (MAC). To achieve this, general practice guidelines call for the careful titration of the chosen sedative using incremental doses. The most commonly used agents are benzodiazepines, alone or in combination with an analgesic, and propofol, alone or also in combination with another agent.²¹,²6,²² The choice of sedating agent is largely dependent on the provider based on what he thinks and feels is the best in maximizing patient comfort at the same time, minimizing risks and complications. A US survey noted that over 85% of endoscopists use or prefer to use midazolam over diazepam. Only 10% have indicated

The two most commonly used benzodiazepines are midazolam (Versed) and diazepam (Valium). **Midazolam** (Versed) is also classified as an anesthetic adjunct and as a short or intermediate acting hypnotic. It depresses subcortical levels in the Central Nervous System, may potentiate -aminobutyric acid (GABA), and may act on the limbic system and reticular formation. It is used for preoperative sedation, anxiety, intubation procedures, induction of general anesthesia, and for diagnostic endoscopic procedures. It can also be used for

sedation during endoscopic procedures such as colonoscopy, midazolam can be used alone or in combination with a narcotic (e.g. an analgesic like meperidine or fentanyl). It is administered immediately prior to the procedure and supplemented by small incremental

Usual dosing for a healthy adult below 60 years of age range from 1mg to 2.5mg titrated slowly (within 2 minutes). Allow a 2-3 minute interval or more before administering any additional doses, and after each incremental dose to fully evaluate the desired sedative effect. A total dose greater than 5mg is usually not necessary and patients given an additional narcotic may only require 30% less of this drug, because of the cumulative CNS depressant effect (Product Info midazolam hcl injection, 2005). Patients 60 years and older, chronically ill, debilitated or with renal or hepatic insufficiency will require less, 1mg to 1.5mg titrated slowly intravenously (maximum infusion rate is 0.75mg/min). Again, allow 2 or more minutes before each additional dose to evaluate the desired sedative effect. A total dose of greater than 3.5mg is not necessary and individuals will normally require 50% less than what a normal healthy adult would receive especially if a narcotic were also added. An elderly patient should not receive a dose of more than 1.5mg. The peak effect of the drug may take longer and the danger of apnea or hypoventilation is greater. Metabolites of midazolam can accumulate in patients with renal and hepatic failure and may prolong the sedative effect. Administration of midazolam is contraindicated in patients with hypersensitivity to any component of the drug, hypersensitivity to midazolam, acute narrow-angle glaucoma, untreated open-angle glaucoma, pregnancy, and status

Midazolam is 97% protein bound; has a half-life of 1.8-6.4 hours; metabolized in the liver; excreted in the urine; and crosses the placenta and blood-brain barriers. Given intravenously, it has an onset of 1-5min, for a duration of 1-3 hours. Side effects of the drug include: headache, anxiety, insomnia, retrograde amnesia, euphoria, confusion, agitation, paresthesia, slurred speech, agitation, chills, arrhythmias, nausea, vomiting, hiccups,

doses throughout until the desired effect is achieved to complete the procedure.²¹

refractory status epilepticus. For moderate sedation or conscious

**7. Commonly used sedation agents**

preference for using diazepam.9

**7.1 Benzodiazepines**

asthmaticus.³²

reduces the amount of time they stay in the discharge area and contributes to cost reduction and unit efficiency.⁷

Table 3. Modified Aldrete Scoring System

\*AP = arterial pressure

\*\* = peripheral oxygen saturation

Table 3a. Aldrete and Kroulik Index

reduces the amount of time they stay in the discharge area and contributes to cost reduction

**Modified Aldrete Scoring**

**Criteria Ability Score**

Ability to move voluntarily or on command: Four extremities Two extremities No movement

Able to cough and breathe deeply freely Dyspnea, shallow or limited breathing Apnea

Blood pressure within 20mm Hg of pre-sedation level Blood pressure within 20-50mm Hg of pre-sedation level Blood pressure + 50mm Hg of pre-sedation level

> Fully awake Arousable on calling Not responding

Able to maintain O2 saturation >92% on room air Needs O2 to maintain O2 saturation >90% O2 saturation is <90% even with O2 supplementation

**Assessment Item Condition Grade**  Moves 4 extremities 2 Muscle Activity Moves 2 extremities 1 Moves 0 extremities 0 Deep, Cough 2 Breathing Limited, Dyspnea 1 Apnea 0 Fully awake 2 Consciousness Awakens when called 1 Does not respond to call 0 + of 20% of pre-anesthesia level 2

 level 1 + 50% of pre-anesthesia level 0 Maintains SpO2 >92% in ambient air 2 SpO2\*\* Maintains SpO2 > 90% with O2 1 Maintains SpO2 <90% with O2 0

Circulation (AP)\* + 20% to 49% of pre-anesthesia

2 1 0

2 1 0

2 1 0

2 1 0

2 1 0

and unit efficiency.⁷

Activity

Respiration

Circulation

Consciousness

O2 Saturation

\*AP = arterial pressure

\*\* = peripheral oxygen saturation

Table 3a. Aldrete and Kroulik Index

Table 3. Modified Aldrete Scoring System

#### **7. Commonly used sedation agents**

Colonoscopy procedures are usually done under moderate level of sedation or moderate anesthesia care (MAC). To achieve this, general practice guidelines call for the careful titration of the chosen sedative using incremental doses. The most commonly used agents are benzodiazepines, alone or in combination with an analgesic, and propofol, alone or also in combination with another agent.²¹,²6,²² The choice of sedating agent is largely dependent on the provider based on what he thinks and feels is the best in maximizing patient comfort at the same time, minimizing risks and complications. A US survey noted that over 85% of endoscopists use or prefer to use midazolam over diazepam. Only 10% have indicated preference for using diazepam.9

#### **7.1 Benzodiazepines**

The two most commonly used benzodiazepines are midazolam (Versed) and diazepam (Valium). **Midazolam** (Versed) is also classified as an anesthetic adjunct and as a short or intermediate acting hypnotic. It depresses subcortical levels in the Central Nervous System, may potentiate -aminobutyric acid (GABA), and may act on the limbic system and reticular formation. It is used for preoperative sedation, anxiety, intubation procedures, induction of general anesthesia, and for diagnostic endoscopic procedures. It can also be used for refractory status epilepticus. For moderate sedation or conscious

sedation during endoscopic procedures such as colonoscopy, midazolam can be used alone or in combination with a narcotic (e.g. an analgesic like meperidine or fentanyl). It is administered immediately prior to the procedure and supplemented by small incremental doses throughout until the desired effect is achieved to complete the procedure.²¹

Usual dosing for a healthy adult below 60 years of age range from 1mg to 2.5mg titrated slowly (within 2 minutes). Allow a 2-3 minute interval or more before administering any additional doses, and after each incremental dose to fully evaluate the desired sedative effect. A total dose greater than 5mg is usually not necessary and patients given an additional narcotic may only require 30% less of this drug, because of the cumulative CNS depressant effect (Product Info midazolam hcl injection, 2005). Patients 60 years and older, chronically ill, debilitated or with renal or hepatic insufficiency will require less, 1mg to 1.5mg titrated slowly intravenously (maximum infusion rate is 0.75mg/min). Again, allow 2 or more minutes before each additional dose to evaluate the desired sedative effect. A total dose of greater than 3.5mg is not necessary and individuals will normally require 50% less than what a normal healthy adult would receive especially if a narcotic were also added. An elderly patient should not receive a dose of more than 1.5mg. The peak effect of the drug may take longer and the danger of apnea or hypoventilation is greater. Metabolites of midazolam can accumulate in patients with renal and hepatic failure and may prolong the sedative effect. Administration of midazolam is contraindicated in patients with hypersensitivity to any component of the drug, hypersensitivity to midazolam, acute narrow-angle glaucoma, untreated open-angle glaucoma, pregnancy, and status asthmaticus.³²

Midazolam is 97% protein bound; has a half-life of 1.8-6.4 hours; metabolized in the liver; excreted in the urine; and crosses the placenta and blood-brain barriers. Given intravenously, it has an onset of 1-5min, for a duration of 1-3 hours. Side effects of the drug include: headache, anxiety, insomnia, retrograde amnesia, euphoria, confusion, agitation, paresthesia, slurred speech, agitation, chills, arrhythmias, nausea, vomiting, hiccups,

Monitoring During Colonoscopy 73

benzodiazepines is that since they are fat-soluble (particularly diazepam), repeated dose results in accumulation of the drug in the adipose tissues which is subsequently released into the bloodstream resulting in prolonged effects. Hence, the most common reasons for missing work were feeling weak and drowsy or having abdominal cramping and bloating.²² Over sedation can be reversed with the administration of 0.2mg IV flumazenil (Romazicon,

The sedative and amnesic effects of benzodiazepines often times do not provide adequate comfort for patients undergoing endoscopic procedures, especially if the procedure lasts longer than half-an-hour. For this reason, opiates are often added to achieve optimum sedation and analgesia. Very few studies have been done to evaluate the efficacy of adding an opiate prior to colonoscopy and authors have casted doubt on its benefit.⁸,¹º,¹⁷ The two

**Meperidine** (Demerol) is an analgesic, anesthetic adjunct, and is an opioid. It is indicated as an anesthetic adjunct, for obstetrical pain, and as premedication for a procedure. It depresses pain impulses at the spinal cord level by interacting with opioid receptors. For endoscopic procedures, meperidine is dosed as follows: initial bolus of 25mg (given slowly) and subsequent incremental doses of 25mg every 2-3 minutes until the desired effect is achieved. Colonoscopy is usually started two to three minutes after the initial bolus of meperidine and midazolam and titration delivery was given every three minutes thereafter with meperidine 25mg and midazolam 1mg until the desired sedation effect was achieved,

Meperidine is readily absorbed and crosses the blood-brain and placental barriers. It is 65- 80% protein bound, metabolized in the liver and excreted in the kidneys. It has an elimination half-life of 3.2-3.7 hours. It is contraindicated in individuals with hypersensitivity to meperidine and those who are taking MAOI (monoamine oxidase inhibitor) drugs. Use with caution in individuals with low blood volume, receiving concomitant CNS depressants (reduce dosage), head injury, impaired respiratory function, acute abdominal conditions, Addison's disease (reduce dosage), elderly, debilitated, hypothyroidism, prostatic hypertrophy and urethral strictures, seizures (may induce more), severe hepatic and renal impairment, cardiac dysrhythmias such as SVTs and A-flutter. Side effects include: CNS: drowsiness, dizziness, confusion, headache, sedation, euphoria, increased intracranial pressure, seizures and serotonin syndrome; CV: palpitations, bradycardia, hypotension and orthostatic hypotension, tachycardia; EENT: tinnitus, blurred vision, miosis, diplopia, depressed corneal reflex; GI: nausea, vomiting, anorexia, constipation, cramps, biliary spasm, and paralytic ileus; GU: urinary retention, dysuria; Integ: rash, urticarial, bruising, flushing, diaphoresis, xerostomia and pruritus. Adverse effects include respiratory depression, cardiac arrest and anaphylaxis. Use judiciously when used in conjunction with benzodiazepines because of its added CNS and respiratory

The other opioid of choice is **fentanyl** which shares the same classification as meperidine: analgesic, anesthetic adjunct, and opioid. It acts by inhibiting the ascending pain pathways in the CNS (central nervous system), increases pain threshold, and alters pain perception by binding to opioid receptors. It is used to control moderate to severe pain, as an adjunct to general and regional anesthesia, and premedication for procedures requiring conscious

commonly used opiates are meperidine (Demerol) and fentanyl.

i.e. ptosis, slurred speech, and sleep. See Table 2 for dosing guidelines.

Anexate).

**7.2 Opiates**

depressant effects.³²

increased salivation, urticaria, swelling and/or itchiness at injection site, and coughing. Serious adverse effects of the drug include: apnea, cardio-respiratory arrest (occurs usually in combination with a narcotic), oxygen desaturation, hypotension, respiratory depression, respiratory obstruction, bronchospasm and laryngospasm. Unopened vials are stored at room temperature (between 68-77 degrees Fahrenheit or 20-25 degrees Celsius) and are stable up to 36 days. Protect from light.³² Over sedation can be reversed with the administration of 0.2 mg IV flumazenil (Romazicon, Anexate).

**Diazepam** (Valium) works similarly as midazolam. It is a member of the following classes: antianxiety, anticonvulsant, benzodiazepine, and long-acting skeletal muscle relaxant. It potentiates the actions of -aminobutyric acid (GABA), especially in the limbic system and reticular formation; enhances presympathetic inhibition, and inhibits spinal polysynaptic afferent paths. It is used for anxiety, acute alcohol withdrawal, as an adjunct in seizure disorders; as a relaxant both preoperatively and general skeletal muscle relaxation (adjunct for skeletal muscle spasm). Given rectally, it is used in acute repetitive (refractory) seizures. Other uses of diazepam are: for agitation, benzodiazepine withdrawal, chloroquine overdose, insomnia, and as seizure prophylaxis.³² For sedation during endoscopic procedures, a dose of 10 mg or less is given intravenously prior to the procedure for a maximum dose of 20 mg. Patients 60 years and older, chronically ill, debilitated or with hepatic insufficiency will require less. There are no specific dose adjustments in patients with renal insufficiency. Due to the irritating nature of the drug, administration **must be done slowly**, no faster than 5mg/min., and if given through IV infusion tubing, give as close to the IV insertion site as possible. Do not inject into small veins (irritating and may cause phlebitis) or through intravenous sets made of polyvinyl chloride (PVC). Diazepam binds to polyvinyl chloride.³²

Contraindications to its administration are severe hepatic insufficiency, hypersensitivity to diazepam, myasthenia gravis, acute narrow-angle glaucoma, severe respiratory insufficiency, sleep apnea, and children less than 6 months of age. Diazepam is 99% protein bound (and significantly greater in males than in females), metabolized extensively in the liver and excreted in the urine. It is excreted in breast milk, crosses the placenta and bloodbrain barriers. It has a half-life of 30-60 hours. Given intravenously, it has an immediate effect and has a duration of about 15 minutes to an hour. Side effects are similar to midazolam and include: dizziness, drowsiness, confusion, headache, anxiety, tremors, stimulation, fatigue, depression, insomnia, hallucinations, ataxia, hypotension, ECG changes and tachycardia. Some, especially for prolonged users, experience blurred vision, tinnitus, mydriasis, nystagmus, constipation, dry mouth, nausea, vomiting, diarrhea, anorexia, neutropenia, rash, dermatitis, and itching. Injectable diazepam can be stored at room temperature and has been found to maintain stability up to 5 months; otherwise, store at temperatures 25 degree Celsius (77̊ F) or lower to prevent deterioration.

Both diazepam and midazolam are similar in producing effective sedation prior to short surgical as well as endoscopic procedures. However, midazolam produced a greater degree of amnesia, lesser pain on injection, and lesser phlebitis at injection site than diazepam. It also produced a greater respiratory depression than diazepam during the first 45minutes of administration, though the latter sustained the effects longer than midazolam after an hour of administration. Midazolam was also more acceptable to patients than those given diazepam. Hence, midazolam is now the agent of choice when amnesia and adequate sedation is required. One disadvantage, though, noted with the administration of benzodiazepines is that since they are fat-soluble (particularly diazepam), repeated dose results in accumulation of the drug in the adipose tissues which is subsequently released into the bloodstream resulting in prolonged effects. Hence, the most common reasons for missing work were feeling weak and drowsy or having abdominal cramping and bloating.²² Over sedation can be reversed with the administration of 0.2mg IV flumazenil (Romazicon, Anexate).

#### **7.2 Opiates**

72 Endoscopic Procedures in Colon and Rectum

increased salivation, urticaria, swelling and/or itchiness at injection site, and coughing. Serious adverse effects of the drug include: apnea, cardio-respiratory arrest (occurs usually in combination with a narcotic), oxygen desaturation, hypotension, respiratory depression, respiratory obstruction, bronchospasm and laryngospasm. Unopened vials are stored at room temperature (between 68-77 degrees Fahrenheit or 20-25 degrees Celsius) and are stable up to 36 days. Protect from light.³² Over sedation can be reversed with the

**Diazepam** (Valium) works similarly as midazolam. It is a member of the following classes: antianxiety, anticonvulsant, benzodiazepine, and long-acting skeletal muscle relaxant. It potentiates the actions of -aminobutyric acid (GABA), especially in the limbic system and reticular formation; enhances presympathetic inhibition, and inhibits spinal polysynaptic afferent paths. It is used for anxiety, acute alcohol withdrawal, as an adjunct in seizure disorders; as a relaxant both preoperatively and general skeletal muscle relaxation (adjunct for skeletal muscle spasm). Given rectally, it is used in acute repetitive (refractory) seizures. Other uses of diazepam are: for agitation, benzodiazepine withdrawal, chloroquine overdose, insomnia, and as seizure prophylaxis.³² For sedation during endoscopic procedures, a dose of 10 mg or less is given intravenously prior to the procedure for a maximum dose of 20 mg. Patients 60 years and older, chronically ill, debilitated or with hepatic insufficiency will require less. There are no specific dose adjustments in patients with renal insufficiency. Due to the irritating nature of the drug, administration **must be done slowly**, no faster than 5mg/min., and if given through IV infusion tubing, give as close to the IV insertion site as possible. Do not inject into small veins (irritating and may cause phlebitis) or through intravenous sets made of polyvinyl chloride (PVC). Diazepam

Contraindications to its administration are severe hepatic insufficiency, hypersensitivity to diazepam, myasthenia gravis, acute narrow-angle glaucoma, severe respiratory insufficiency, sleep apnea, and children less than 6 months of age. Diazepam is 99% protein bound (and significantly greater in males than in females), metabolized extensively in the liver and excreted in the urine. It is excreted in breast milk, crosses the placenta and bloodbrain barriers. It has a half-life of 30-60 hours. Given intravenously, it has an immediate effect and has a duration of about 15 minutes to an hour. Side effects are similar to midazolam and include: dizziness, drowsiness, confusion, headache, anxiety, tremors, stimulation, fatigue, depression, insomnia, hallucinations, ataxia, hypotension, ECG changes and tachycardia. Some, especially for prolonged users, experience blurred vision, tinnitus, mydriasis, nystagmus, constipation, dry mouth, nausea, vomiting, diarrhea, anorexia, neutropenia, rash, dermatitis, and itching. Injectable diazepam can be stored at room temperature and has been found to maintain stability up to 5 months; otherwise, store at

Both diazepam and midazolam are similar in producing effective sedation prior to short surgical as well as endoscopic procedures. However, midazolam produced a greater degree of amnesia, lesser pain on injection, and lesser phlebitis at injection site than diazepam. It also produced a greater respiratory depression than diazepam during the first 45minutes of administration, though the latter sustained the effects longer than midazolam after an hour of administration. Midazolam was also more acceptable to patients than those given diazepam. Hence, midazolam is now the agent of choice when amnesia and adequate sedation is required. One disadvantage, though, noted with the administration of

temperatures 25 degree Celsius (77̊ F) or lower to prevent deterioration.

administration of 0.2 mg IV flumazenil (Romazicon, Anexate).

binds to polyvinyl chloride.³²

The sedative and amnesic effects of benzodiazepines often times do not provide adequate comfort for patients undergoing endoscopic procedures, especially if the procedure lasts longer than half-an-hour. For this reason, opiates are often added to achieve optimum sedation and analgesia. Very few studies have been done to evaluate the efficacy of adding an opiate prior to colonoscopy and authors have casted doubt on its benefit.⁸,¹º,¹⁷ The two commonly used opiates are meperidine (Demerol) and fentanyl.

**Meperidine** (Demerol) is an analgesic, anesthetic adjunct, and is an opioid. It is indicated as an anesthetic adjunct, for obstetrical pain, and as premedication for a procedure. It depresses pain impulses at the spinal cord level by interacting with opioid receptors. For endoscopic procedures, meperidine is dosed as follows: initial bolus of 25mg (given slowly) and subsequent incremental doses of 25mg every 2-3 minutes until the desired effect is achieved. Colonoscopy is usually started two to three minutes after the initial bolus of meperidine and midazolam and titration delivery was given every three minutes thereafter with meperidine 25mg and midazolam 1mg until the desired sedation effect was achieved, i.e. ptosis, slurred speech, and sleep. See Table 2 for dosing guidelines.

Meperidine is readily absorbed and crosses the blood-brain and placental barriers. It is 65- 80% protein bound, metabolized in the liver and excreted in the kidneys. It has an elimination half-life of 3.2-3.7 hours. It is contraindicated in individuals with hypersensitivity to meperidine and those who are taking MAOI (monoamine oxidase inhibitor) drugs. Use with caution in individuals with low blood volume, receiving concomitant CNS depressants (reduce dosage), head injury, impaired respiratory function, acute abdominal conditions, Addison's disease (reduce dosage), elderly, debilitated, hypothyroidism, prostatic hypertrophy and urethral strictures, seizures (may induce more), severe hepatic and renal impairment, cardiac dysrhythmias such as SVTs and A-flutter. Side effects include: CNS: drowsiness, dizziness, confusion, headache, sedation, euphoria, increased intracranial pressure, seizures and serotonin syndrome; CV: palpitations, bradycardia, hypotension and orthostatic hypotension, tachycardia; EENT: tinnitus, blurred vision, miosis, diplopia, depressed corneal reflex; GI: nausea, vomiting, anorexia, constipation, cramps, biliary spasm, and paralytic ileus; GU: urinary retention, dysuria; Integ: rash, urticarial, bruising, flushing, diaphoresis, xerostomia and pruritus. Adverse effects include respiratory depression, cardiac arrest and anaphylaxis. Use judiciously when used in conjunction with benzodiazepines because of its added CNS and respiratory depressant effects.³²

The other opioid of choice is **fentanyl** which shares the same classification as meperidine: analgesic, anesthetic adjunct, and opioid. It acts by inhibiting the ascending pain pathways in the CNS (central nervous system), increases pain threshold, and alters pain perception by binding to opioid receptors. It is used to control moderate to severe pain, as an adjunct to general and regional anesthesia, and premedication for procedures requiring conscious

Monitoring During Colonoscopy 75

The drug is highly lipophilic. There are two preparations that exist on the market. One is prepared as an oil/water emulsion (Diprivan) consisting of 1% propofol, 10% soybean oil, 2.25% glycerol, 1.2% egg lecithin and the antimicrobial agent, EDTA. This preparation is contraindicated in individuals with propofol, soy or egg hypersensitivities or allergies. The other generic preparation has bisulfites (sodium metabisulfite) as the antimicrobial agent and is therefore, contraindicated in individuals with hypersensitivity or allergy to

Propofol is notorious for being painful at the injection site, often described as a burning sensation. Several approaches have been employed to minimize this discomfort. One is the administration of 1-2 ml of 1% lidocaine prior to injecting propofol or mixing lidocaine and propofol in the same syringe. Another approach is diluting propofol in a 5% glucose solution. A study found that there was less pain at the injection site in individuals given the

Propofol is a category B drug and should be used with caution in lactating mothers as it is excreted in breast milk. It is 98% plasma-protein bound, is metabolized primarily in the liver, and excreted in the kidneys. Usual time from injection to onset of sedation is anywhere from 13-30 seconds and the duration is about 4-8 minutes.⁴ Table 4 shows a summary of

**Guidelines**

Bolus 25mg slowly and incremental doses of 25 mg every 2-3 min. titrated to effect

Bolus 0.5-2mg with incremental doses of 2-5mg every 2-3 min titrated to effect

**Onset/ Peak**

5 min./ Peaks in 10 min.

1-5 min./ Peaks in 3-5 min.

**Duration/**

2-4 hrs. / Half-life of 3-5 hrs.

1-3 hrs. / Half-life of 1.8-6.4 hrs.

**Half-life Adverse Effects**

Respiratory depression, seizures, hypotension, nausea, vomiting tachycardia, and hypoventilation, SVTs confusion, euphoria

Apnea, hypotension, hypoventilation, cardiac arrhythmias (PVCs), bronchospasm, anxiety, laryngospasm, dyspnea, respiratory depression, headache, agitation

generic propofol (bisulfite-containing propofol) than those given Diprivan.³²

**Class Effects Dosing**

Sedation Analgesia

Sedation Amnesia Anxiolytic

bisulfites.⁴,³²

**Drug (Trade Name)**

Meperidine (Demerol)

Midazolam (Versed)

commonly used drugs in colonoscopy.

Opioid Anesthetic adjunct Analgesic

Benzodiazepine Anesthetic adjunct Short or intermediate hypnotic

sedation, such as colonoscopy. Compared to meperidine, fentanyl has a more rapid onset of action and clearance. It also has a lesser incidence of nausea than meperidine.

For procedural sedation, the suggested doses are 0.5 to 1.5mcg/kg intravenously and repeated every 1 to 3 minutes until the desired sedative effects is achieved. **Administer slowly to prevent rigidity**. It is metabolized by the liver, excreted in the kidneys and breast milk and crosses the placenta. Given intravenously, its onset is immediate, within a minute, peaking in 3-5 minutes for ½-1 hour. It has a half-life of 1 ½-6 hours and is 80% bound to plasma proteins. Side effects are similar to meperidine and include: dizziness, delirium, bradycardia, hypo/hypertension, blurred vision, miosis, nausea, vomiting, constipation, urinary retention, rash, diaphoresis, muscle rigidity, cardio-respiratory depression and/or arrest, and laryngospasm. It is contraindicated in individuals with myasthenia gravis and those with hypersensitivity to opiates, bronchial asthma, paralytic ileus, situations of significant respiratory distress.³²

Opioids and benzodiazepines combined work synergistically. Antagonists of these medications are naloxone (Narcan) for opiates (typical dose is 40-400mcg IV) and flumazenil (Romazicon) for benzodiazepines (typical dose is 40-400mcg IV). These drugs should be readily available in every GI suite to rescue a patient who has been given too much sedative and whose cardiorespiratory status is compromised.

#### **7.3 General anesthetic**

The only drug used in colonoscopy in this category is **propofol** (Diprivan). It produces a dose-dependent CNS depression by activating the GABA receptors. Its principal uses are for the induction and maintenance of anesthesia and sedation in mechanically ventilated patients. It also potentiates the effects on the central nervous system of analgesics and sedatives such as benzodiazepines and barbiturates. It has a rapid onset of sedation, but also marked cardio-respiratory depressant properties. These side effects usually rapidly diminish or reverse with reduction of dose or stopping of administration or infusion of propofol. There has been an increase in its use in endoscopic procedures because of its rapid onset and faster recovery to alertness properties with minimal residual sedative effects, which makes it an attractive alternative to the longer half-life benzodiazepines.²²,¹¹ Do not use within 10 days of intake of monoamine oxidase inhibitors (MAOI). This drug potentiates CNS depression in individuals taking antipsychotic drugs, opioids, skeletal muscle relaxants, St. John's wort and alcohol.³²

Propofol may be used alone or in combination with other agents such an opioid or benzodiazepine. When used alone, higher doses are often required to achieve the desired sedation level which increases the risks of dose-related side effects such as hypotension, respiratory depression, and bradycardia. In combination with other agents, the clinician can adjust the dosages which usually results in administration of smaller dosages of each of the agents to achieve moderate sedation level. If necessary, the effects of the opioid and benzodiazepine can be reversed with naloxone and flumazenil. Propofol does not have an antidote or reversal agent as its half-life is short and the effects wear off as soon as the infusion of the drug is stopped.9

Though theoretically, propofol in combination with an opioid or benzodiazepine will decrease the rapid recovery benefit seen with administration of propofol alone, a randomized control trial proved otherwise. The results showed a shorter recovery time with the combination regimen than the propofol alone.³⁵

sedation, such as colonoscopy. Compared to meperidine, fentanyl has a more rapid onset of

For procedural sedation, the suggested doses are 0.5 to 1.5mcg/kg intravenously and repeated every 1 to 3 minutes until the desired sedative effects is achieved. **Administer slowly to prevent rigidity**. It is metabolized by the liver, excreted in the kidneys and breast milk and crosses the placenta. Given intravenously, its onset is immediate, within a minute, peaking in 3-5 minutes for ½-1 hour. It has a half-life of 1 ½-6 hours and is 80% bound to plasma proteins. Side effects are similar to meperidine and include: dizziness, delirium, bradycardia, hypo/hypertension, blurred vision, miosis, nausea, vomiting, constipation, urinary retention, rash, diaphoresis, muscle rigidity, cardio-respiratory depression and/or arrest, and laryngospasm. It is contraindicated in individuals with myasthenia gravis and those with hypersensitivity to opiates, bronchial asthma, paralytic ileus, situations of

Opioids and benzodiazepines combined work synergistically. Antagonists of these medications are naloxone (Narcan) for opiates (typical dose is 40-400mcg IV) and flumazenil (Romazicon) for benzodiazepines (typical dose is 40-400mcg IV). These drugs should be readily available in every GI suite to rescue a patient who has been given too much sedative

The only drug used in colonoscopy in this category is **propofol** (Diprivan). It produces a dose-dependent CNS depression by activating the GABA receptors. Its principal uses are for the induction and maintenance of anesthesia and sedation in mechanically ventilated patients. It also potentiates the effects on the central nervous system of analgesics and sedatives such as benzodiazepines and barbiturates. It has a rapid onset of sedation, but also marked cardio-respiratory depressant properties. These side effects usually rapidly diminish or reverse with reduction of dose or stopping of administration or infusion of propofol. There has been an increase in its use in endoscopic procedures because of its rapid onset and faster recovery to alertness properties with minimal residual sedative effects, which makes it an attractive alternative to the longer half-life benzodiazepines.²²,¹¹ Do not use within 10 days of intake of monoamine oxidase inhibitors (MAOI). This drug potentiates CNS depression in individuals taking antipsychotic drugs, opioids, skeletal muscle