Effect of intra-abdominal pressure level on gastric intramucosal pH during pneumoperitoneum. [Postlaparoscopic pain syndrome. Results of a prospective, randomized study]. Hemodynamic consequences of high- and low-pressure capnoperitoneum during laparoscopic cholecystectomy. Randomized trial of different insufflation pressures for laparoscopic cholecystectomy. Prospective randomized trial on low-pressure versus standard-pressure pneumoperitoneum in outpatient laparoscopic cholecystectomy. Influence of different pressures of pneumoperitoneum on the autonomic system function during laparoscopy. A prospective randomized trial on comparison of low-pressure (LP) and standard-pressure (SP) pneumoperitoneum for laparoscopic cholecystectomy. Randomized trial of different intraabdominal pressures and acid-base balance alterations during laparoscopic cholecystectomy. Randomized comparison between different insufflation pressures for laparoscopic cholecystectomy. Lactate and acid base changes during laparoscopic cholecystectomy. Effects of low and high intra-abdominal pressure on immune response in laparoscopic cholecystectomy. The effect of different intraabdominal pressures on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy. Postoperative changes in liver function tests: randomized comparison of low- and high-pressure laparoscopic cholecystectomy. Randomized, prospective comparison of postoperative pain in low- versus high-pressure pneumoperitoneum.
The present study was designed to examine the effect of intra-abdominal pressure level on gastric intramucosal pH using gastric tonometry during pneumoperitoneum. One hundred patients were prospectively randomized into 5 equal groups (N = 20 each). Intra-abdominal pressure levels were 8, 10, 12, 14, and 16 mm Hg in groups I, II, III, IV, and V, respectively. Intramucosal pH measurement was done 2 times: 30 minutes following insufflation and 1 hour after the ending of the surgery. In the first and second measurements, intramucosal pH values were found as 7.39 +/- 0.02 and 7.36 +/- 0.03 in group I; 7.41 +/- 0.03 and 7.38 +/- 0.03 in group II; 7.37 +/- 0.03 and 7.37 +/- 0.03 in group III; 7.36 +/- 0.03 and 7.37 +/- 0.03 in group IV; and 7.39 +/- 0.03, 7.36 +/- 0.03 in group V, respectively. Statistical significance was not found in the comparison of these values within the groups and between the groups (P > 0.005, for each). In conclusion, intra-abdominal pressure between 8 and 16 mm Hg did not cause significant difference in gastric intramucosal pH. The so-called post-laparoscopic algesia is a specific impairment of about 63% of the patients who undergo laparoscopic surgical operations. This impairment takes the form of mild to moderate shoulder pain. Eliminating the causes of pain has a clear advantage over symptomatic treatment using analgetics, a fact worth a good consideration especially with the post-operative sojourn at the hospital becoming shorter and shorter. In a prospective controlled study, involving 42 patients subdivided into four groups namely, higher or lower insufflation pressures, chemically inert insufflation gas and control groups; the use of analgetics, lung function, operation duration, amount of insufflated gas, intraperitoneal pH-values and post-operative complications in the various subgroups were compared to each other with regard to post-operative pain perception. The results did not show any significant differences among the groups regarding the main parameters like pH-value or different insufflation pressures etc. These results led to the termination of the study based on the raised criteria since we anticipated the actual cause of the shoulder pain to be due to an unknown factor. By the evaluation of the individual data, it became apparent that, the pains increase with increasing gas consumption, a fact which led to assumption that the pains are caused by a physical effect such as the cooling of the peritoneum. Peritoneal insufflation to 15 mmHg diminishes venous return and reduces cardiac output. Such changes may be dangerous in patients with a poor cardiac reserve. The aim of this study was to investigate the hemodynamic effects of high (15 mmHg) and low (7 mmHg) intraabdominal pressure during laparoscopic cholestectomy (LC) METHODS: Twenty patients were randomized to either high- or low-pressure capnoperitoneum. Anesthesia was standardized, and the end-tidal CO2 was maintained at 4.5 kPa. Arterial blood pressure was measured invasively. Heart rate, stroke volume, and cardiac output were measured by transesophageal doppler.
                There were 10 patients in each group. In the high-pressure group, heart rate (HR) and mean arterial blood pressure (MABP) increased during insufflation. Stroke volume (SV) and cardiac output were depressed by a maximum of 26% and 28% (SV 0.1 > p > 0.05, cardiac output p > 0. 1). In the low-pressure group, insufflation produced a rise in MABP and a peak rise in both stroke volume and cardiac output of 10% and 28%, respectively (p < 0.05).
                Low-pressure pneumoperitoneum is feasible for LC and minimizes the adverse hemodynamic effects of peritoneal insufflation. The factors affecting cardiorespiratory changes and postoperative pain after laparoscopic cholecystectomy are poorly understood. The aim of this study was to assess these changes in patients undergoing laparoscopic cholecystectomy at an insufflation pressure of 7.5 or 15 mmHg.
                Forty patients with similar preoperative characteristics were randomized, 20 to each group.
                There were no significant differences in intraoperative heart rate or cardiac index although the latter fell significantly soon after insufflation in both groups. The fall in cardiac index lasted longer (7 versus 2 min) and coincided with a slower rise in mean arterial pressure in those having 15 mmHg insufflation. Changes in peak airway pressure, end-tidal carbon dioxide and arterial blood gases were similar. After operation the low-pressure group had significantly less pain, better preservation of pulmonary function and were discharged home sooner (P = 0.015).
                Insufflation pressure significantly affects the haemodynamic changes and postoperative pain associated with laparoscopic cholecystectomy. Inpatient low-pressure pneumoperitoneum laparoscopic cholecystectomy (LPLC) has been shown to have less postoperative pain (especially shoulder-tip pain). No report so far has documented the use of lower-pressure pneumoperitoneum in outpatient laparoscopic cholecystectomy (LC). A prospective randomized trial was conducted in Tung Wah Hospital, Day Surgery Centre from January 2004 to December 2004. A total of 40 patients were recruited and 20 of whom were allocated to each arm. Outcome measures included operation time, treatment-related morbidity, mortality, postoperative pain (eg, shoulder-tip pain), consumption of analgesics, and level of satisfaction. All patients in both groups could be discharged on the same day. Patients' demographics and operation time were comparable in both groups. There were no treatment-related morbidity and mortality, nor was there any significant difference in postoperative pain. Less shoulder-tip pain was observed in the LPLC group though without significant difference (5% vs. 20%; P=0.151). Three patients in the LPLC group needed higher insufflation pressure (12 mm Hg) because of inadequate exposure and adhesions, and the operations were successful in all of them. Otherwise, no conversion to open procedure was noted in both groups. The consumption of analgesics was minimal and a high level of satisfaction was achieved in both groups of patients. The present study demonstrated no difference in LPLC and standard-pressure pneumoperitoneum laparoscopic cholecystectomy in the outcomes of outpatient LC. Routine use of lower-pressure pneumoperitoneum in outpatient LC would not be recommended unless in selected straightforward cases. The effects of different pressure values of pneumoperitoneum on the activity of the autonomic nervous system (ANS) have not been investigated in detail. In this prospective study, 20 patients qualified for laparoscopic cholecystectomy were randomised to either low-pressure (LP = 7 mmHg) or standard-pressure (SP = 12 mmHg) pneumoperitoneum groups, 10 patients each. The anesthesia was induced with fentanyl and thiopental and maintained with isoflurane. Ventilation was mechanically controlled (18 breaths per minute, end-tidal CO2 30-35 mmHg, instant capnometer monitoring). Intraabdominal pressure was maintained automatically by a CO2 insufflator. Patient were kept in a horizontal position. The ANS was evaluated by heart rate variability (HRV) analysis (POSTER ECG 2002 System) measured intraoperatively in three recordings of 5 minutes each: in awake patient, after induction of general anesthesia, and after creation of pneumoperitoneum. Power spectral analysis of HRV was applied, the low-frequency (LF = 0.05-0.15 Hz) and high frequency (HF = 0.15-0.45 Hz) spectral density of the HRV were analysed using the Fast Fourier Transform algorithm. The appropriate statistical analysis of data was performed. LF density decreased at the anesthetized stage and increased at the insufflated stage in both groups (p < 0.01). LP resulted in lower sympathetic activation than SP pneumoperitoneum (LF: 68.12 +/- 6.56 nu vs. 78.26 +/- 5.43 nu, p < 0.01; HF: 24 +/- 2.48 nu vs. 15.56 +/- 2.54 nu, p < 0.05). In conclusion: pneumoperitoneum leads to sympathetic activation of the ANS. LP in comparison to SP pneumoperitoneum with carbon dioxide results in significantly decreased sympathetic activation during laparoscopy. This study aimed to investigate the advantages and disadvantages of LP (7 mmHg) in comparison to SP (12 mm Hg) pneumoperitoneum in a prospective randomized clinical trial.
                148 consecutive patients qualified for laparoscopic cholecystectomy (LC) due to uncomplicated symptomatic gallstones were randomized to either SPLC or LPLC. All the procedures were performed by the same experienced team of surgeons. The statistical analysis included sex, mean age, body mass index, ASA grade, operative time, complication rate, conversion rate, postoperative pain assessed by the Visual Analogue Scale of Pain (VAS) including the incidence of shoulder-tip pain, postoperative hospital stay, recovery time, and the quality of life (QOL) within 7 days following the operation. p <0.05 was considered as indicative of significance.
                Neither conversion to an open procedure nor major complications occurred in either group. The operative time was similar in both groups (LP 55.7 +/- 8.6 min vs SP 51.9 +/- 8.3 min). The mean postoperative pain score was 6.18 +/- 3.48 lower after LP than SPLC and the difference amounted to 22.2% (p <0.005). The incidence of shoulder-tip pain was 2.1 times lower after LP than SPLC (p <0.05). QOL within 7 days following the operation was remarkably better after LPLC than after SPLC (p <0.01).
                LP pneumoperitoneum is superior to SP pneumoperitoneum in terms of lower postoperative pain, a lower incidence of shoulder-tip pain, and a better QOL within 5 days following the operation. LP should be used for LC in cases of uncomplicated symptomatic gallstones as a recommended procedure as long as an adequate exposure is obtained with this technique. Experimental and clinical studies document risks of acid-base balance alterations toward acidosis and hypercapnia during intraperitoneal carbon dioxide insufflation. The aim of this study was to assess the influence of different insufflation pressures on arterial blood gas changes and acid-base alterations during laparoscopic cholecystectomy and immediately postoperatively.
                Thirty patients were randomized to receive either 10 or 15 mmHg insufflation pressure. Anesthesia was standardized for both groups. The following parameters of acid-base balance were recorded: pH, pCO2, pO2, base excess (BE), HCO3. Suitable data were analyzed by the Mann-Whitney U-test.
                Pneumoperitoneum with carbon dioxide caused a decrease in pH toward acidosis that was either respiratory or mixed in origin. There were no statistically significant differences in acid-base balance alterations between the two groups of patients.
                Carbon dioxide pneumoperitoneum causes alterations of the acid-base balance, mostly of respiratory or mixed type. Lowering of the insufflation pressure from 15 to 10 mmHg does not contribute to the elimination of acid-base balance alterations during laparoscopic cholecystectomy. Laparoscopy using carbon dioxide insufflation induces adverse effects in both the cardiovascular and the respiratory function. The use of low pressure pneumoperitoneum has been shown to reduce adverse hemodynamic effects. However, its effect on tissue trauma and postoperative pain and recovery remains controversial. The aim of this study was to compare tissue trauma, postoperative pain, and recovery in two groups of patients undergoing laparoscopic cholecystectomy, one at insufflation pressure of 8 (LC8) and the other at 15 mm Hg (LC15). Forty patients were randomized, 20 in each group. The characteristics of the patients were similar in the two groups. The procedure was completed in all patients in the LC15 group, but in 2 patients in the LC8 group the pressure was increased to 15 mm Hg to complete the operation. There were no significant differences in postoperative pain scores, analgesic consumption, and the incidence of nausea, vomiting, and shoulder pain between the two groups. C-reactive protein concentrations and white blood cell count rose significantly after surgery, but the increase was similar in the two groups. The median duration of surgery was similar, 23 minutes (range 15-65) in the LC8 group and 25 minutes (range 15-80) in the LC15 group. Using our technique of laparoscopic cholecystectomy, there were no advantages to tissue damage, postoperative pain, and recovery when a low pressure pneumoperitoneum was used. The observation of hemodynamic and metabolic impairment related to CO2 pneumoperitoneum and postoperative mesenteric ischemia reports following laparoscopic procedures have raised concern about local and systemic effects of increase intraabdominal pressure during laparoscopic procedures. The present study aims to evaluate the metabolic and acid base responses of using high pressure versus low pressure pneumoperitonium in patients undergoing laparoscopic cholecystectomy in a prospective randomized clinical trial.
                20 ASA I-II patients scheduled for elective laparoscopic cholecystectomy were randomly allocated to one of two study groups; high pressure pneumoperitoneum 12-14mmHg (HPP, n=10) versus low pressure pneumoperitoneum 6-8mmHg (LPP, n=10) undergoing laparoscopic cholecystectomy. Arterial blood gases and lactate levels were determined after induction of anesthesia (before pneumoperitonium), then after 10 min, then 30 min after insufflations and at the end of surgery and 1 hour postoperatively. Nurses in recovery unit reported pain assessment starting postoperatively until 3 hours on a 10mm VAS (0-10). Statistical significant was established at P<0.05.
                Bicarbonate was significantly (P>0.0412) lower in high pressure group at 30 min and 60 min after insufflations. In high pressure group lactate levels increased significantly as compared to low pressure group, (at 30 minutes after the establishment of abdominal pneumatic inflation P<0.006 and remained significantly increased (P<0.001) until the end of surgery and one hour thereafter) (P<0.001). The mean postoperative pain score during second hour (VAS) at HPP group was 7.4 +/- 1.17 which is significantly (P < or = 0.006) higher than pain score in LPP group 5.0 +/- 1.886. Shoulder tip pain was reported in 3 patients in the high pressure group and only one patient in the lower pressure group.
                High-pressure pneumoperitonium causes statistically significant elevation in the arterial lactate level intraoperatively until one hour post operatively. It also causes higher pain score and shoulder tip pain. Immunosuppression is directly related to the degree of trauma. The aim of this study is to compare the effects of low and high intra-abdominal pressure on immune response in moderate surgical trauma.
                Twenty-two patients, scheduled for laparoscopic cholecystectomy, were randomly allocated to one of 2 groups according to intra-abdominal pressure: low and high intra-abdominal pressure. This study was conducted in the Hacettepe University Faculty of Medicine, Operation Room, Ankara, Turkey. Serum interleukin (IL)-2 and IL-6 levels were measured.
                Serum IL-2 showed a significant decrease before the incision in high intra-abdominal pressure group. The increase in serum IL-6 at the end of surgery and postoperatively was lower in low intra-abdominal pressure group.
                These results, can be interpreted as the immune system, are less depressed when there is lower intra-abdominal pressure. This may have clinical implications in immunocompromised patients. This prospective, randomized, and controlled study was designed to investigate the effects of different intraabdominal pressures (IAPs) on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy (LC).
                Twenty-four patients (12 men, 12 women) who underwent LC at either 10 or 15 mmHg of IAP were randomized into two groups. Repeated blood samples were collected to measure thiobarbituric acid reactive substances (TBARS) levels to assess lipid peroxidation and protein carbonyl content and protein sulfhydryl groups to assess protein oxidation status.
                Serum protein carbonyls and TBARS levels were found to be increased immediately after desufflation in both study groups when compared to the preoperative levels. On the other hand, protein sulfhydryl levels were found to be decreased in both study groups. Although increases in protein carbonyls and TBARS levels were more prominent in patients who underwent LC at 15 mmHg of IAP, this difference was not statistically significant between both groups.
                The results suggest that both 15 and 10 mmHg of LAP could lead to an increased oxidative stress response during LC, but no difference was found between the groups. Pneumporeitoneum at 14 mmHg causes dangerous hemodynamic disturbances in some patients, leading to splanchnic ischemia. Laparoscopic cholecystectomy (LC) using low-pressure pneumoperitoneum (7 mmHg) minimizes adverse hemodynamic effects on hepatic portal blood flow and hepatic function. This study evaluated the changes in liver function tests after high-pressure LC (HPLC; 14 mmHg) and low-pressure LC (LPLC; 7 mmHg).
                For this study, 50 patients were randomly assigned to undergo either HPLC (n = 25) or LPLC (n = 25) Liver function tests including total bilirubin, gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were obtained preoperatively, then 24 and 48 h postoperatively. All patients had normal values on the preoperative liver function tests. The anesthesiologic protocol was uniform.
                The findings showed that ALT after 24 h (LPLC: 1473.72 +/- 654.85; HPLC: 2233.74 +/- 1247.33; p = 0.0096) and 48 h (LPLC: 1322.99 +/- 601.51; HPLC 2007.80 +/- 747.55; p = 0.0008) and AST after 24 h (LPLC: 1189.96 +/- 404.79 i.j.; HPLC: 1679.40 +/- 766.13; p = 0.0069) were increased in the patients who underwent HPLC. The AST levels after 48 h were statistically unchanged from baseline in both groups. Total bilirubin, ALP, and GGT levels remained unchanged from baseline in both groups, without a significant difference between the two groups.
                Because LPLC minimizes adverse hemodynamic effects on hepatic function, a low-pressure pneumoperitoneum should be considered for patients with compromised liver function, particularly those undergoing prolonged laparoscopic surgery. Reduced postoperative pain after laparoscopic cholecystectomy (LC) compared to open cholecystectomy (OC) may be able to be further optimized. To reduce pain, focus should be directed on the effects of individual components of pain.
                A double-blind, randomized, controlled trial was carried out in a tertiary care hospital. Fifty-three elective patients with symptomatic gallstones were enrolled into the study. Patients were randomized to low- or high-pressure pneumoperitoneum groups. In all patients, gas pressure was set to 15 mmHg during placement of ports. Later on, in the low-pressure group, the rest of the procedure was performed at 10 mmHg pressure. At 6 and 24 h postoperatively, a short-form McGill Questionnaire (MPQ) was obtained from all patients. Patients were then asked to complete a 10-cm visual analogue scale (VAS) for abdominal pain.
                Pain scores were generally low for both groups. Statistical comparisons of mean cumulative McGill score and VAS abdominal pain scores in both groups did not reach statistical significance at 6 and 24 h after operation.
                There was no correlation between high- and low-pressure laparoscopy and postoperative pain after LC. Peritoneal stretching may be more responsible for shoulder pain but has less effect on intensity of abdominal pain or incisional pain. On the basis of these negative findings, routine use of low-pressure pneumoperitoneum for alleviation of postoperative pain following LC is not recommended.
Low pressure pneumoperitoneum appears effective in decreasing pain after laparoscopic cholecystectomy. The safety of low pressure pneumoperitoneum has to be established.