2.5: Experimental and Non-experimental Research
One of the big distinctions that you should be aware of is the distinction between “experimental research” and “non-experimental research”. When we make this distinction, what we’re really talking about is the degree of control that the researcher exercises over the people and events in the study.
Experimental research
The key features of experimental research is that the researcher controls all aspects of the study, especially what participants experience during the study. In particular, the researcher manipulates or varies the predictor variables (IVs), and then allows the outcome variable (DV) to vary naturally. The idea here is to deliberately vary the predictors (IVs) to see if they have any causal effects on the outcomes. Moreover, in order to ensure that there’s no chance that something other than the predictor variables is causing the outcomes, everything else is kept constant or is in some other way “balanced” to ensure that they have no effect on the results. In practice, it’s almost impossible to think of everything else that might have an influence on the outcome of an experiment, much less keep it constant. The standard solution to this is randomisation: that is, we randomly assign people to different groups, and then give each group a different treatment (i.e., assign them different values of the predictor variables). We’ll talk more about randomisation later in this course, but for now, it’s enough to say that what randomisation does is minimise (but not eliminate) the chances that there are any systematic difference between groups.
Let’s consider a very simple, completely unrealistic and grossly unethical example. Suppose you wanted to find out if smoking causes lung cancer. One way to do this would be to find people who smoke and people who don’t smoke, and look to see if smokers have a higher rate of lung cancer. This is not a proper experiment, since the researcher doesn’t have a lot of control over who is and isn’t a smoker. And this really matters: for instance, it might be that people who choose to smoke cigarettes also tend to have poor diets, or maybe they tend to work in asbestos mines, or whatever. The point here is that the groups (smokers and non-smokers) actually differ on lots of things, not just smoking. So it might be that the higher incidence of lung cancer among smokers is caused by something else, not by smoking per se. In technical terms, these other things (e.g. diet) are called “confounds”, and we’ll talk about those in just a moment.
In the meantime, let’s now consider what a proper experiment might look like. Recall that our concern was that smokers and non-smokers might differ in lots of ways. The solution, as long as you have no ethics, is to control who smokes and who doesn’t. Specifically, if we randomly divide participants into two groups, and force half of them to become smokers, then it’s very unlikely that the groups will differ in any respect other than the fact that half of them smoke. That way, if our smoking group gets cancer at a higher rate than the non-smoking group, then we can feel pretty confident that (a) smoking does cause cancer and (b) we’re murderers.
Non-experimental research
Non-experimental research is a broad term that covers “any study in which the researcher doesn’t have quite as much control as they do in an experiment”. Obviously, control is something that scientists like to have, but as the previous example illustrates, there are lots of situations in which you can’t or shouldn’t try to obtain that control. Since it’s grossly unethical (and almost certainly criminal) to force people to smoke in order to find out if they get cancer, this is a good example of a situation in which you really shouldn’t try to obtain experimental control. But there are other reasons too. Even leaving aside the ethical issues, our “smoking experiment” does have a few other issues. For instance, when I suggested that we “force” half of the people to become smokers, I must have been talking about starting with a sample of non-smokers, and then forcing them to become smokers. While this sounds like the kind of solid, evil experimental design that a mad scientist would love, it might not be a very sound way of investigating the effect in the real world. For instance, suppose that smoking only causes lung cancer when people have poor diets, and suppose also that people who normally smoke do tend to have poor diets. However, since the “smokers” in our experiment aren’t “natural” smokers (i.e., we forced non-smokers to become smokers; they didn’t take on all of the other normal, real life characteristics that smokers might tend to possess) they probably have better diets. As such, in this silly example they wouldn’t get lung cancer, and our experiment will fail, because it violates the structure of the “natural” world (the technical name for this is an “artifactual” result; see later).
One distinction worth making between two types of non-experimental research is the difference be- tween quasi-experimental research and case studies. The example I discussed earlier – in which we wanted to examine incidence of lung cancer among smokers and non-smokers, without trying to control who smokes and who doesn’t – is a quasi-experimental design. That is, it’s the same as an experiment, but we don’t control the predictors (IVs). We can still use statistics to analyse the results, it’s just that we have to be a lot more careful.
The alternative approach, case studies, aims to provide a very detailed description of one or a few instances. In general, you can’t use statistics to analyse the results of case studies, and it’s usually very hard to draw any general conclusions about “people in general” from a few isolated examples. However, case studies are very useful in some situations. Firstly, there are situations where you don’t have any alternative: neuropsychology has this issue a lot. Sometimes, you just can’t find a lot of people with brain damage in a specific area, so the only thing you can do is describe those cases that you do have in as much detail and with as much care as you can. However, there’s also some genuine advantages to case studies: because you don’t have as many people to study, you have the ability to invest lots of time and effort trying to understand the specific factors at play in each case. This is a very valuable thing to do. As a consequence, case studies can complement the more statistically-oriented approaches that you see in experimental and quasi-experimental designs. We won’t talk much about case studies in these lectures, but they are nevertheless very valuable tools!


33.1.8: Phylum Annelida
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Learning Objectives
- Describe the morphological and anatomical features of annelids
Phylum Annelida
Phylum Annelida contains the class Polychaeta (the polychaetes) and the class Oligochaeta (the earthworms, leeches, and their relatives). These animals are found in marine, terrestrial, and freshwater habitats, but a presence of water or humidity is a critical factor for their survival, especially in terrestrial habitats. The name of the phylum is derived from the Latin word annellus, which means a small ring. Animals in this phylum show parasitic and commensal symbioses with other species in their habitat. Approximately 16,500 species have been described in phylum Annelida. The phylum includes earthworms, polychaete worms, and leeches. Annelids show protostomic development in embryonic stages and are often called “segmented worms” due to their key characteristic of metamerism, or true segmentation.
Morphology
Annelids display bilateral symmetry and are worm-like in overall morphology. They have a segmented body plan where the internal and external morphological features are repeated in each body segment. Metamerism allows animals to become bigger by adding “compartments,” while making their movement more efficient. This metamerism is thought to arise from identical teloblast cells in the embryonic stage, which develop into identical mesodermal structures. The overall body can be divided into head, body, and pygidium (or tail). The clitellum is a reproductive structure that generates mucus that aids in sperm transfer and gives rise to a cocoon within which fertilization occurs; it appears as a fused band in the anterior third of the animal.
Anatomy
The epidermis is protected by an acellular, external cuticle, but this is much thinner than the cuticle found in the ecdysozoans and does not require periodic shedding for growth. Circular as well as longitudinal muscles are located interior to the epidermis. Chitinous hairlike extensions, anchored in the epidermis and projecting from the cuticle, called setae/chaetae are present in every segment. Annelids show the presence of a true coelom, derived from embryonic mesoderm and protostomy. Hence, they are the most advanced worms. A well-developed and complete digestive system is present in earthworms (oligochaetes) with a mouth, muscular pharynx, esophagus, crop, and gizzard being present. The gizzard leads to the intestine and ends in an anal opening. Each segment is limited by a membranous septum that divides the coelomic cavity into a series of compartments.
Annelids possess a closed circulatory system of dorsal and ventral blood vessels that run parallel to the alimentary canal as well as capillaries that service individual tissues. In addition, these vessels are connected by transverse loops in every segment. These animals lack a well-developed respiratory system; gas exchange occurs across the moist body surface. Excretion is facilitated by a pair of metanephridia (a type of primitive “kidney” that consists of a convoluted tubule and an open, ciliated funnel) that is present in every segment towards the ventral side. Annelids show well-developed nervous systems with a nerve ring of fused ganglia present around the pharynx. The nerve cord is ventral in position, bearing enlarged nodes or ganglia in each segment.
Annelids may be either monoecious, with permanent gonads (as in earthworms and leeches), or dioecious, with temporary or seasonal gonads that develop (as in polychaetes). However, cross-fertilization is preferred in hermaphroditic animals. These animals may also show simultaneous hermaphroditism, participating in simultaneous sperm exchange when they are aligned for copulation.
Earthworms are the most abundant members of the class Oligochaeta, distinguished by the presence of the clitellum as well as few, reduced chaetae (“oligo- = “few”; -chaetae = “hairs”). The number and size of chaetae are greatly diminished in Oligochaeta compared to the polychaetes (poly=many, chaetae = hairs). The many chetae of polychaetes are also arranged within fleshy, flat, paired appendages that protrude from each segment. These parapodia may be specialized for different functions in the polychates. A significant difference between leeches and other annelids is the development of suckers at the anterior and posterior ends and an absence of chaetae. Additionally, the segmentation of the body wall may not correspond to the internal segmentation of the coelomic cavity. This adaptation possibly helps the leeches to elongate when they ingest copious quantities of blood from host vertebrates.
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Key Points
- Annelids are often called “segmented worms” because they possess true segmentation of their bodies, with both internal and external morphological features repeated in each body segment.
- The clitellum is a structure on the anterior portion of the worm that generates mucus to aid in sperm transfer from one worm to another; it also forms a cocoon within which fertilization occurs.
- Most annelids have chitinous hairlike extensions in every segment called chaetae that are anchored in the epidermis, although the number and size of chaetae can vary in the different classes.
- Annelids possess a closed circulatory system, lack a well-developed respiratory system, but have well-developed nervous systems.
- Annelids can either have distinct male and female forms or be hermaphrodites (having both male and female reproductive organs). Earthworms are hermaphrodites and can self-fertilize, but prefer to cross-fertilize if possible.
Key Terms
- clitellum : a glandular swelling in the epidermis of some annelid worms; it secretes a viscous fluid in which the eggs are deposited
- chaeta : a chitinous bristle of an annelid worm
- metamerism : the segmentation of the body into similar discrete units


17.4: Class III- Potassium Channel Blockers
By the end of this section, you should be able to:
- 17.4.1 Identify the characteristics of the potassium channel blocker drugs used to treat dysrhythmias.
- 17.4.2 Explain the indications, actions, adverse reactions, and interactions of potassium channel blocker drugs used to treat dysrhythmias.
- 17.4.3 Describe the nursing implications of potassium channel blocker drugs used to treat dysrhythmias.
- 17.4.4 Explain the client education related to potassium channel blocker drugs used to treat dysrhythmias.
Potassium channel blockers are class III drugs. They work by blocking the potassium channels that facilitate potassium transport and mediate repolarization of the cardiac cells. They extend the action potential and slow repolarization. All antidysrhythmic drugs that block potassium channels are proarrhythmic. They lead to a prolonged QT interval, which increases the risk for torsade de pointes. Because of this, all drugs within this class require ECG monitoring for QT interval assessment. The nurse must also be vigilant to consider concomitant drugs that increase the QT interval because concomitant use can have additive effects. Although all drugs within this class block potassium channels, many have additional antidysrhythmic mechanisms.
Clinical Tip
Monitor Potassium Channel Blockers Using the Corrected QT Interval
The QT interval changes depending on the client’s heart rate. To standardize assessment, the QT interval can be corrected (adjusted) for heart rate using various methods. This correction is referred to as the QTc and is usually used in drug titration and safety algorithms. The most common formula for QTc is known as the Bazett formula. Various websites have QTc calculators , and some ECG software calculates the QTc automatically.
The following medications are all classified as potassium channel blockers; however, it is important to note their additional mechanisms of action as well.
Amiodarone and Dronedarone
Amiodarone is a class III antidysrhythmic drug; however, it has all four Vaughan Williams mechanisms: It blocks sodium channels (class I), functions as a beta-adrenergic blocker (class II), blocks potassium channels (class III), and blocks calcium channels (class IV). It is available in both intravenous and oral dosage forms. Amiodarone is known for having a very long half-life (greater than 1 month); thus, the duration of action can be several months after chronic therapy ends. The nurse should be aware that even after amiodarone administration is discontinued, its effects will be apparent for several weeks to months.
Amiodarone has many notable drug interactions. When metabolism occurs in the liver, it does so by the hepatic microsomal enzyme system. A key component of this system is an enzyme complex known as cytochrome P450 or CYP450. This enzyme metabolizes drugs, nutrients, and other substances such as steroids and cholesterol. CYP3A, CYP2C8, and others are isoenzymes of CYP450 and perform slightly different metabolic functions. The thing to remember is that these enzymes determine the speed of the metabolism of drugs and affect many drug-drug interactions. Amiodarone is a substrate for CYP3A and CYP2C8, so inducers and inhibitors of those enzymes affect the client’s exposure to amiodarone. Amiodarone is also an inhibitor of P-glycoprotein and CYP1A2, CYP2C9, CYP2D6, and CYP3A; this can increase the client’s exposure to other drugs that are substrates of those enzymes. Some drug interactions include:
- Digoxin: Amiodarone can increase digoxin concentrations. Therefore, it is recommended that digoxin doses be decreased (with careful monitoring) or discontinued altogether if amiodarone is initiated.
- Warfarin: Concomitant administration of warfarin and amiodarone increases the anticoagulant effect of warfarin. It is recommended to decrease the warfarin dose by one-third to one-half and to monitor prothrombin time.
- Statin medications: Concomitant administration of certain statin medications with amiodarone can result in increased concentrations of the statin drug. Lower starting doses of statin medications may be required; the maximum recommended dose for lovastatin is 40 mg and for simvastatin is 20 mg during concomitant use with amiodarone.
Dronedarone is like amiodarone in that it is categorized as a class III drug with all four Vaughan Williams mechanisms of action. It is approved to treat clients with paroxysmal or persistent atrial fibrillation. Because of the potential for teratogenicity, dronedarone is also classified as a hazardous drug; nurses should wear gloves when handling or administering it and follow institutional policies for hazardous drugs (Institute for Safe Medication Practices, 2018).
Dronedarone interacts with many drugs because it is an inhibitor of CYP3A and CYP2D6. Medications it interacts with include digoxin, calcium channel blockers, and statins.
Dofetilide and Ibutilide
Dofetilide and ibutilide are both pure class III antidysrhythmic medications with no additional mechanisms of action. Dofetilide is an oral medication used for atrial fibrillation and atrial flutter. It has a high risk for causing proarrhythmia, specifically torsade de pointes. Therefore, dofetilide must be initiated in a health care setting capable of providing cardiac resuscitation services and continuous ECG monitoring for a minimum of 3 days. The manufacturer’s labeling provides detailed guidance for dosing and monitoring. Dofetilide is contraindicated in clients with a baseline QTc greater than 440 msec, and the drug should either be dose-adjusted or discontinued if the QTc rises above 500 msec during therapy, depending on the circumstance. Before starting dofetilide, clients should have electrolyte levels checked (potassium, magnesium), and electrolyte supplements should be administered to maintain adequate levels. Renal function must also be monitored because dofetilide is excreted by the kidneys.
Ibutilide is an intravenous class III antidysrhythmic medication. It is used almost exclusively for conversion of recent-onset atrial fibrillation or atrial flutter to sinus rhythm and given as only one or two doses (no chronic maintenance dosing). Ibutilide has a high risk for causing torsade de pointes (1.7% in registry studies; DailyMed Ibutilide fumarate , 2020) and should be prescribed by health care providers who are familiar with identifying and treating acute ventricular arrhythmias. It requires continuous ECG monitoring and observation for at least 4 hours after administration. Clients with atrial fibrillation for more than 2–3 days require anticoagulation for 2 weeks before administration to mitigate the risk for stroke upon cardioversion. Clients with chronic atrial fibrillation are not candidates for cardioversion using ibutilide because it is less effective than in paroxysmal (i.e., intermittent) atrial fibrillation and is associated with high risks.
Sotalol
Sotalol is another class III antidysrhythmic drug; however, in addition to its mechanism as a potassium channel blocker, it also has beta-adrenergic blocking effects. (Note that the name ends in “lol” like other beta-adrenergic blockers.) Sotalol is available in both oral and intravenous dosage forms and is approved for the treatment of symptomatic atrial fibrillation/flutter and life-threatening ventricular arrhythmias.
As with all potassium channel blockers, sotalol prolongs the QTc interval and can cause torsade de pointes. Therefore, sotalol requires inpatient initiation in a facility that can provide cardiac resuscitation services and continuous ECG monitoring. If the client’s baseline QTc interval is longer than 450 msec, sotalol should not be initiated. The manufacturer’s labeling provides detailed directions for initiation and monitoring. During initiation, the client’s ECG is monitored after every dose; once stable, it is monitored periodically for the duration of therapy. If the QTc interval increases to more than 500 msec during therapy, the dosing interval must be lengthened or the drug discontinued.
Sotalol is eliminated via the kidneys; thus, clients with severe renal dysfunction should not take sotalol, and renal function should be monitored periodically in all clients who take sotalol.
Table 17.7 lists common potassium channel blockers and typical routes and dosing for adult clients.
| Drug | Routes and Dosage Ranges |
|---|---|
|
Amiodarone
( Nexterone , Pacerone ) |
Ventricular dysrhythmias:
Oral: 800–1600 mg daily until therapeutic response occurs (usually 1–3 weeks), then reduce to 600–800 mg daily for 1 month, then 400 mg orally once daily. IV: For the first 24 hours, administer 150 mg IV over the first 10 minutes, followed by 360 mg IV over the next 6 hours, followed by 540 mg IV over the remaining 18 hours. After the first 24 hours, continue the maintenance infusion rate of 0.5 mg/min. |
|
Dronedarone
( Multaq ) |
Atrial fibrillation: 400 mg orally twice daily. |
|
Dofetilide
( Tikosyn ) |
Atrial fibrillation: 500 mcg orally every 12 hours; precise dosing is required, with doses spaced 12 hours apart. |
|
Ibutilide
( Corvert ) |
Atrial fibrillation/atrial flutter: 1 mg IV once. If dysrhythmia has not stopped by 10 minutes after completion of administration, a second dose may be given (dosing applies to clients who weigh at least 60 kg). |
|
Sotalol
( Betapace , Betapace AF , Sorine ) |
Ventricular dysrhythmias:
160 mg orally twice daily.
Atrial fibrillation/atrial flutter: 80–120 mg orally twice daily. |
Adverse Effects and Contraindications
All class III drugs are proarrhythmic and can cause QT prolongation, leading to torsade de pointes. Aside from that, the adverse effect profile depends on the agent being used.
Amiodarone has many potential toxicities and adverse effects, which include:
- Optic neuropathy and/or optic neuritis, which can lead to permanent blindness; corneal microdeposits that may be reversible
- Photosensitivity resulting in a bluish-gray discoloration of the skin
- New arrhythmias, including torsade de pointes
- Hyperthyroidism or hypothyroidism
- Hepatotoxicity
- Acute and chronic pulmonary toxicity, including acute respiratory distress syndrome and pulmonary fibrosis
Because of these toxicities, amiodarone requires baseline monitoring as well as follow-up monitoring at least every 3–6 months. Clients should minimally receive the following tests at baseline and periodically after initiation:
- Cardiac monitoring, including an ECG to assess heart rate, medication efficacy, and the QT interval
- Pulmonary function tests and a chest x-ray
- Liver function tests
- Thyroid function tests
- Ophthalmic exams
As with all beta-adrenergic blockers and calcium channel blockers, amiodarone can cause bradycardia, hypotension, and fatigue. Amiodarone carries multiple boxed warnings from the FDA related to arrhythmias, pulmonary toxicity, and hepatotoxicity. It is on the Beers Criteria® list of high-risk medications for older adults because of its potential for toxicity (American Geriatrics Society, 2019). Amiodarone should not be used in clients with bradycardia at baseline unless they have a pacemaker. Amiodarone has iodine within its chemical structure; thus, it is contraindicated in clients with iodine hypersensitivity.
Dronedarone has many of the same adverse effects as amiodarone, including heart failure, hepatotoxicity, QT prolongation/torsade de pointes, and pulmonary toxicity. Because of a particularly high risk for adverse reactions, including death, it is contraindicated in clients with heart failure and those in atrial fibrillation who cannot be converted to sinus rhythm; these contraindications are listed as boxed warnings from the FDA. Dronedarone is contraindicated in pregnant clients due to the potential for teratogenicity.
Dofetilide and sotalol are contraindicated in clients with severe kidney disease.
Sotalol, like all beta-adrenergic blockers, can cause bradycardia, hypotension, and fatigue and should be used cautiously in clients with asthma and heart failure.
Table 17.8 is a drug prototype table for potassium channel blockers featuring dofetilide. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
|
Drug Class
Potassium channel blocker antidysrhythmic Mechanism of Action Blocks the potassium channels responsible for repolarization of the cell, leading to a prolonged action potential and prolonged refractoriness |
Drug Dosage
Atrial fibrillation/atrial flutter: 500 mcg orally every 12 hours; precise dosing is required, with doses spaced 12 hours apart. |
|
Indications
Atrial fibrillation and atrial flutter Therapeutic Effects Converts atrial fibrillation to sinus rhythm Maintains sinus rhythm after cardioversion |
Drug Interactions
Cimetidine Trimethoprim Ketoconazole Prochlorperazine Dolutegravir Megestrol Potassium-depleting diuretics (e.g., hydrochlorothiazide) Drugs that prolong the QT interval Food Interactions No significant interactions |
|
Adverse Effects
QT prolongation Torsade de pointes Chest pain Headache |
Contraindications
Hypersensitivity Baseline QTc greater than 440 msec Severe renal impairment (creatinine clearance less than 20 mL/min) Caution: Renal impairment |
Nursing Implications
The nurse should do the following for clients who are taking potassium channel blockers:
- Perform a complete medication history to assess for relevant drug interactions, including other drugs that also prolong the QTc interval.
- Monitor ECG (including QTc interval), vital signs, and electrolyte levels.
- Be prepared to perform cardiac resuscitation on any client starting on a class III antidysrhythmic drug.
- Follow the specific dosing and monitoring protocols described in the manufacturer’s labeling for a client initiating sotalol or dofetilide.
- Observe the client closely for at least 4 hours after administration of ibutilide for maintenance of sinus rhythm and adverse effects such as ventricular arrhythmias.
- Conduct in-depth education for any client being started on amiodarone.
- Monitor for amiodarone-related toxicity in any client taking the drug and for several months after amiodarone discontinuation.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Client Teaching Guidelines
The client taking a potassium channel blocker should:
- Communicate their baseline medication list and any new medications (such as antibiotics) to their prescribing health care provider.
- Seek emergency medical attention if they experience symptoms of torsade de pointes (dizziness, palpitations, lightheadedness, syncope).
- Keep appointments for laboratory testing to monitor for potential toxicities.
The client taking amiodarone should:
- Avoid direct sunlight and wear sunscreen and protective clothing.
- Report symptoms of hyperthyroidism (heat sensitivity, anxiety, weight loss) or hypothyroidism (fatigue, weight gain, cold sensitivity).
- Report any vision changes or breathing difficulties.
- Avoid eating grapefruits or drinking grapefruit juice.
FDA Black Box Warning
Amiodarone
Amiodarone can cause pulmonary toxicity (hypersensitivity pneumonitis or interstitial/alveolar pneumonitis) that has resulted in clinically manifest disease at rates as high as 17% in some series of clients. Pulmonary toxicity has been fatal about 10% of the time. The client should have a baseline chest x-ray and pulmonary function tests, including diffusion capacity, when amiodarone therapy is initiated. The medical history, physical exam, and chest x-ray should be repeated every 3–6 months.
Amiodarone also can cause hepatotoxicity, which can be fatal. Baseline and periodic liver transaminase levels should be obtained, and the medication should be discontinued or reduced in dose if the level exceeds three times the normal level or doubles in a client with an elevated baseline. Amiodarone should be stopped if the client experiences signs or symptoms of clinical liver injury.
Amiodarone is intended for use only in clients with indicated life-threatening arrhythmias because its use is accompanied by substantial toxicity.
In addition, amiodarone can exacerbate arrhythmias. Amiodarone must be initiated in a clinical setting where continuous ECG monitoring and cardiac resuscitation are available.
Dronedarone
Dronedarone is contraindicated in clients with symptomatic heart failure with recent decompensation requiring hospitalization or in clients with New York Heart Association class IV heart failure. Dronedarone doubles the risk of death in these clients. Dronedarone is contraindicated in clients in atrial fibrillation who will not or cannot be cardioverted into normal sinus rhythm. In clients with permanent atrial fibrillation, dronedarone doubles the risk of death, stroke, and hospitalization for heart failure.
Dofetilide
To minimize the risk for induced arrhythmia, clients initiated or reinitiated on dofetilide should be admitted for a minimum of 3 days into a facility that can provide calculations of creatinine clearance, continuous ECG monitoring, and cardiac resuscitation.
Sotalol
To minimize the risk of drug-induced arrhythmia, clients should be initiated, reinitiated, or up-titrated in a facility that can provide cardiac resuscitation and continuous ECG monitoring. Sotalol can cause life-threatening ventricular tachycardia associated with QT interval prolongation. A client whose baseline QTc is longer than 450 msec should not start sotalol therapy. If the QT interval lengthens to 500 msec or more, the dose should be reduced, the dosing interval lengthened, or the drug discontinued. The creatinine clearance should be calculated to determine appropriate dosing.


8.3: Medical Systems
Naturalistic System
Naturalistic Systems can be an approach to the explanation, diagnosis, and treatment of illness which focuses on the underlying bio-mechanical processes behind human disorder. Naturalistic medicine is largely the foundation of the Western model of bio-medicine and practitioners rely heavily on the use of imaging technologies and the scientific method to develop treatment plans. Philosophically, naturalists approach human disorder from the perspective that illness is impersonal and that there is always an identifiable source of pathology in the diagnostic process.
Personalistic System
Largely uncommon in the developed world, the personalistic approach to medicine explains human disorder in terms of preternatural sources of pathology (such as spiritual possession or religious transgression). Illness is considered unique to the patient and medical practitioners often call upon supernatural forces to facilitate the diagnosis and treatment of disorders because the illness is caused by supernatural forces as well. An example of this is the “evil eye.” A person who is envious of another’s good fortune may transfer malignant influence through the “evil eye”, which will result in harm to the recipient.[4]
Modernly, personalistic systems of medicine are most commonly found in small-scale societies. Globally, the personalist approach in decline and has disappeared completely in some cultures. For example, therapeutic shamanism was commonly practiced amongst Inuit peoples and a complex tradition of spiritual healthcare was reported by early ethnographers (see Merkur 85). These traditions are now very rarely practiced and many of the traditional practices have been lost entirely (see Shamanism amongst Eskimo peoples).
Medical Models
Medical models are the explanations of health and illness that are accepted by different cultures. The biomedical model is the most widely accepted medical model by many cultures, including the vast majority of Western culture, but there are multiple other explanations that are accepted by some cultures.
The medical model of disability is a model by which illness or disability is the result of a physical condition, is intrinsic to the individual (it is part of that individual’s own body), may reduce the individual's quality of life, and causes clear disadvantages to the individual.
Some anthropologists believe that the biomedical model is quite provincial. They do not believe that there is enough room for the interpretation of the psychological, behavioral, and social aspects of all of the illnesses. Something called a biopsychosocial [2] model has been proposed. In this there would be more room different aspects of health care.
Humoral
The term Humoral refers to elements in the blood or other fluids that reside within the body. In medicine,the term humor refers to a fluid substance. The aqueous humor is the fluid that normally resides within the front and rear chambers of the eye. The humors were part of an ancient theory that believed that health came from balance between the bodily liquids. These liquids were termed humors. If these fluids were not balanced, a person was more likely to become infected with diseases.
Paired qualities were associated with each humour and its season and element,the humors were:
- Phlegm: winter, water, characteristics: rational, calm, unemotional
- Blood: spring, air, characteristics: courageous, hopeful, amorous
- Gall: (black bile thought to be secreted by the kidneys and spleen) autumn, earth, characteristics: analytical, wise, despondent
- Choler: (yellow bile secreted by the liver) summer, fire, characteristics: short-tempered, fast, irritable
This theory which was also known as the humoral theory, humoralism, and humorism was devised before the time of Hippocrates (c.460-c.375 BC). Today pathology rests on a cellular and molecular foundation. All of the humors have been dispelled, except for the aqueous humor and vitreous humor of the eye. The theory of humors was commonly used until the nineteenth century when modern medical techniques were developed.
The health and healing system of Haiti incorporates humoral-influenced concepts from West Africa. Their system relies on monitoring and regulating their four humors (hot and cold, dry and wet). Eventually their system was simplified, with the dry and wet humors being omitted. They believe a balance is necessary to maintain good health. The balance is affected by the season, how they live and especially how they eat.[5]
Kallawaya Traditional Medicine
The shamans of the Kallawaya people, located in the Andes in Bolivia are an example of humoral medicine. They believe that health and illness are affected by the balance of spirit and soul caused by the earth, or the goddess Pachamama. Their healing art is based in their ability to look into the lives of the ill to see patterns in the day to day aspects such as work, health, routines and relationships and to recognize where there are imbalances. Shamans make use of music, dance, and animal sacrifice to help appease the divine, thus curing illness. The shamans use many herbs, for instance most of the Kallawaya healers have knowledge of at least 300 herbs. They also incorporate alcohol and ayahuasca, which, with the guidance of the shaman, can produce a drug-induced state of healing[6]
Ayurveda
Ayurveda is a 5000-year old traditional system of medicine in India that originated during the Vedic period of Indian history.[3] It is also practiced as an alternative system of medicine in other parts of the world, where yoga, meditation, massage, or healing herbs or foods are used as a supplement to the biomedical model.
Ayurveda is a humoral system, in which blood, chyle, flesh, fat, bone, marrow, and semen are the primary elements. These are divided into air (or spirit), phlegm, and bile, each of which represent a divine force, or dosha. The three doshas are vata (air), pitta (bile) and kapha (phlegm). According to Ayurveda, humans are dominated by one or two of these doshas. Having a balance between the three means that one is in complete health. This balance is achieved through moderation of sleep, sexual intercourse, medicine, and food. Different types of foods are beneficial to people of different doshas. When the doshas are too far out of balance, it can lead to both physical and mental sickness.
Ayurvedic practices include hygienic rituals, ingestion of certain foods and herbs as treatments, and yoga or meditation. The balance between the physical and mental is an important aspect of Ayurvedic healing.
Spiritual Healing
Spiritual healing practices transmit energy to a person in need through means of meditation, prayer, or the presence of a healer, and provide an alternative to standard medical procedures. It is part of the holistic approach to healing which involves the unification and harmony of the mind, body, and spirit in order to achieve wellness. Sickness often originates in the mind so spiritual healing can be beneficial in alleviating stress, coping with emotional issues, and increasing overall happiness. The absence of such mental problems can eliminate physical troubles. For example, meditation aids in lowering heart rate, decreasing high blood pressure, and lessening cholesterol levels because it clears and calms the mind to the extent that stress does not affect the physical state of the body.
A popular and recommended act of spiritual healing, is found in Yoga. It has been said by many that it allows and gives a sense of self-awareness, benefits to positive mental presentation, and overall encourages personal strength and confidence through living a spiritual and healthy lifestyle.
Another act of spiritualism comes through shamanism and shamanistic rituals. The shaman is a person in the community who has been given the power of healing sometimes through divine annunciation, Where god or some form of a deity gives the person the ability to heal. This healing can come in several forms, that of rituals that give the shaman the power to heal, such as the trance dance or boiling energy that the !Kung perform. Another for comes as herbs and medicine that the healer gets knowledge about from the divine connection that they have.
Religion often plays a role in spiritual healing in that people form a relationship with a higher source and are able to channel energy from such a source. This being could be God, nature, or something else meaningful to the individual. It is important to note that if the individual who chooses to form this connection holds full commitment and trust in the higher source, feelings of security, peace of mind, and guidance and are likely to follow, all of which are essential in maintaining a healthy lifestyle.
Kundalini Tantric Yoga
A popular form of spiritual healing is found in Kundalini Tantric Yoga, practiced in various parts of India and the United States. Kundalini energy refers to dormant or spiritual energy within the body that we are usually unaware of. Once Kundalini energy is activated through deep meditation and yoga, the Nadi system, referring to channels of Kundalini energy, is activated as well. This creates a connection between the seven levels of chakras; the centers of consciousness potential that reside along the spine. Each chakra corresponds to a set of desires connected to a certain element.
The first of the seven chakras is called the Muladhara. Its color is red and it is said to lie between the genitals and the scrotom. It governs sexuality and instinct. The second chakra is orange and it is called the Svadhisthana. It lies on the belly and is said to govern, among other things, creativity. Manipura is the third chakra. It is yellow, lies just under the solar plex and controls one's will power. The fourth chakra is the Anhata. Anhata is located near and governs the heart. It is the color green. Vishuddha is the fifth. Its color is turquoise and it governs the voice. It is located in the throat. Ajna, the sixth chakra, is indigo blue. It lies in the brain and governs wisdom. The final chakra can only be tapped upon once all the other chakras have energy flowing through them. It is called Sahasrara. It is purple and it brings enlightenment. It sits on top of the head and is said to inspire universal consciousness and unity.
The goal of Kundalini Tantric yoga is to free oneself from such desires as energy moves higher and higher along the chakras, opening them until it reaches the seventh chakra, called the Sahasra Chakra, located at the top of the cranium. A person can move energy through his or her chakras through tantric yoga, a form of yoga in which one seeks to free the mind of desires through various breathing exercises, contemplation, and meditation. When the seventh chakra is finally opened, a person is said to achieve full consciousness and liberation from the slavery of desires. Through the spiritual experiences one has encountered with the opening of each chakra, the result is inner harmony and overall happiness, which are significant aspects of living a positive, healthy lifestyle.
On a religious note, Hindu mythology offers an explanation for the movement of Kundalini energy throughout the body as one practices Tantric yoga. It is said that the serpent goddess Kundalini Shakti resides at the base of the spine, coiled up around the first chakra. As energy is activated and released through Tantric Yoga, she awakens and rises up the spine, opening the chakras along the way and energizing these conscious potentials. When she reaches the seventh chakra, she is united with her spouse, the God Shiva. Shiva is a symbol of change and the destruction of old habits. Their union leads to the liberation of the individual practicing the yoga, turning them into an “individual of the universe.”
Western Biomedical Model
This is the most popular medical model in medicine today and can be found all across Western societies, as well as others. It looks at humans as biological organisms in order to discover methods for curing diseases and treating illness. This model focuses mainly on physical processes such as physiology and biochemistry and disregards social or spiritual factors. Under the biomedical model, health is defined as the absence of pain or disease, and the body is treated with scientifically-based methods.
It should be noted that the Western approach to biomedical theory and practice is constantly adapting in response to new scientific and philosophical revelations regarding illness. The model focuses on the treatment and cure of disease through medical science, and does not promote disease prevention. In recent years, naturopathic medicine (once largely considered at odds with orthodox bio-medicine)has gained recognition as a viable facet of treatment for a wide variety of disorders. Biomedicine is seen as a model that allows for the repair of the body and to fix problems that happen to the body from the surrounding environment. Biomedicine arose during the industrial revolution as a way to help people recover from diseases that affected them. ( http://www.open.edu/openlearn/body-mind/health/health-studies/what-biomedicine )
One of the criticisms of the Western Biomedical Model is that it discounts the personal knowledge and beliefs of its participants. The system is said to consider ‘professional knowledge’ as the correct, rational, scientific approach while lay beliefs are considered non-rational, unscientific, suppression and are thus ignored. This leads to potential tension between health care providers and patients.[7]
Ethnographic example: The biomedical model has been critical in the development of our country. One of the many influences it has had was treating tuberculosis, a life threatening infectious disease. In 1880, after studying the disease, scientists confirmed that it was contagious. Even before antibiotics this helped to dramatically decrease the number of people that died by using quarantining and sanitizing methods. The first successful immunization was developed in 1906 by Albert Calmette and Camille Guérin. The bovine-strain tuberculosis vaccine (also known known as bacille Calmette–Guérin or BCG), became mainstream after World War II in the U.S., Great Britain and Germany. In the mid 20th century, the antibiotic streptomycin was discovered and offered an effective alternative cure for tuberculosis. Many strains have become resistant to certain antibiotics, however, forcing immunologists to develop new vaccines and treatments to cure more virulent species.
Immunization
The term immunization refers to rendering an organism immune to a specific communicable disease. Immunizations work by triggering the human body to produce antibodies that will help fight a particular disease. The antibody response is created by injecting a small amount of either a dead or live virus, (depending on the virus) into the person receiving the immunization in order to initialize a immune system response to the virus. Therefore in the future if the person who was immunized was exposed to the virus, he or she would already have the antibodies to fend off the virus. Along with the introduction and transmission of many new complex diseases, population growth and the globalization of medicine has brought about the eradication of many previously devastating disorders, including smallpox and polio, through wider availability of immunizations. Many parents in Western countries routinely schedule immunizations for their children to prevent them from contracting a specific communicable disease. While many vaccinations are routine and readily available only in developed nations, the continued globalization of medicine will eventually have a dramatic effect on the improvement of health care in developing countries.[8] [9]
There is a great deal of controversy over vaccination in some cultures regarding the morality, ethics, necessity, safety, and practicality of vaccination have led some parents to keep their children from being vaccinated. Opponents of vaccines claim that they are dangerous, ineffective, and infringe on personal rights.
And example of this is the current debate over whether or not certain vaccines cause autism in children. There is a small but dedicated group of doctors who claim that vaccines may be linked to the onset of autism in children. As a result many parents are insisting their children be exempt from the mandatory vaccines although there are no medical findings which prove the link between the two.[10]


2.2: Web Search Engines
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Web search engines use special software programs (called robots, spiders, or crawlers) to find Web pages and list (or index) all words within each one to make searching large quantities of page faster. Indexes capture the largest amount of information on the Web, but no index lists everything on the Internet.
Commonly used search engines include Google ( https://www.google.com ) and Bing ( http://www.bing.com ).
In addition to search engines, there are also:
Web Search Engines and related web search tools are helpful for locating background information, news (especially if it’s recent), and public opinion.
However, scholarly information is often not available through a regular web search. If you do find scholarly information through a web search engine, especially if you are off campus, you may be asked for payment to access it. Irvine Valley College Library can usually get you what you need without additional payment.
See links above. Use of each tool varies. If a search engine has an advanced search, it may include options such as specifying format, language, domain, or date range.