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Objectives: Studies have shown the advantages of carbon dioxide (CO2) over air insufflation in the adult population during colonoscopies. This study was designed to investigate the efficacy and safety of CO2 insufflation in deeply sedated children undergoing colonoscopy., Methods: This was a prospective, randomized, double-blind clinical trial. We recruited 100 consecutive pediatric patients who had colonoscopy under deep sedation for various indications. Patients were first randomized by history of abdominal pain and then randomly assigned to either CO2 or air insufflation. Postprocedural abdominal pain scores were registered on a 10-point visual analog rating scale and significant pain was defined as a score of 3 or higher. Abdominal circumferences and end tidal CO2 (ETCO2) levels were measured. Complications during and after the procedure were recorded., Results: We did not find statistically significant difference between CO2 and air insufflation on univariate analysis because of low number of children experiencing significant pain after colonoscopy. After adjusting for baseline pain, we found that pain was significantly lower in patients after CO2 versus air insufflation on multivariable analysis (P = 0.03). The significant factors related to pain were duration of the procedure (P = 0.006), history of abdominal pain (P = 0.002) and previous abdominal surgery (P = 0.02). CO2 insufflation was associated with decreased abdominal circumference after colonoscopy (P = 0.002). Girls were more likely to have pain regardless of intervention (P = .04)., Conclusions: Most children tolerate endoscopic procedures without significant pain. Our study was underpowered to show significant difference between air and CO2 on univariate analysis. CO2 insufflation during colonoscopy, however, may reduce postprocedural abdominal pain. Significant factors for increased pain on multivariate analysis included colonoscopy length over 30 minutes, history of abdominal pain, and previous abdominal surgery.

Background and Objective: Endoscopic retrograde cholangiopancreatography (ERCP) is essential for visualising the biliary tree and pancreatic ducts, and carbon dioxide (CO 2 ) insufflation during ERCP is considered an alternative technique to air insufflation for relieving post-procedural abdominal discomfort (abdominal pain and distension). The aim of the present study was to evaluate the effect of CO 2 insufflation on the remission of abdominal discomfort and the potential side effects by conducting a meta-analysis., Methods: The method recommended by the Cochrane Collaboration was employed to conduct a meta-analysis of randomised controlled trials (RCTs) of CO 2 insufflation versus air insufflation during ERCP. The PubMed, EMBASE, Cochrane Library, ISI Web of Science and China Biology Medicine disc (CBMdisc) databases were comprehensively searched., Results: Nine high-quality RCTs were reviewed. The updated meta-analysis showed that the CO 2 groups achieved a lower abdominal pain score [1-hour (SMD: -1.44, 95% CI: -2.76, -0.15), 3-hour (SMD: -1.17, 95% CI: -2.18, -0.16) and 6-hour (SMD: -1.39, 95% CI: -2.68, -0.10)], a lower abdominal distension score [1-hour (SMD: -1.05, 95% CI: -1.73, -0.38), 3-hour (SMD: -0.63, 95% CI: -1.10, -0.16) and 6-hour (SMD: -0.54, 95% CI: -0.99, -0.08)] and a lower overall rate of complications (OR: 0.59; 95% CI: 0.37, 0.93). There was no significant difference between the groups regarding abdominal discomfort immediately after recovery or 24-hour post-procedure. There was no evidence to indicate higher pressure of CO 2 (pCO 2 ) values in the CO 2 groups during the procedure when the patients were under sedation anaesthesia., Conclusions: Compared to air insufflation, CO 2 insufflation is currently the preferred method for ERCP and decreases post-procedural abdominal pain and distension without significant side effects., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background and Aim: CO2 has been reported to be absorbed from the bowel more rapidly than air, resulting in a discomfort reduction after colonoscopy. Its role in deeply sedated patients is limited. This study was designed to investigate the efficacy and safety of CO2 insufflation during colonoscopy in patients deeply sedated with propofol., Methods: A total of 125 continuous patients were randomly assigned to receive either CO2 (n = 63) or air (n = 62) insufflation during propofol-sedated colonoscopy. Postcolonoscopy abdominal pain, distention, and satisfaction were assessed at 1, 3, and 24 h after the procedure, and the proportions of pain-free and distention-free patients were compared. Residual bowel gas in the colon and small bowel was evaluated at 1 h after colonoscopy. End-tidal CO2 and O2 saturation was measured for safety analysis., Results: There was a significant difference between the two groups regarding the postcolonoscopy abdominal pain, distention, and subjective satisfaction at 1 h (P < 0.001) and 3 h (P < 0.01) after the procedure. Patients' pain and distention at 1 and 3 h after the procedure were significantly lower in the CO2 group (P < 0.01). Residual bowel gas in the colon and small bowel was significantly less in the CO2 group (P < 0.001). There was no significant difference in end-tidal CO2 levels between two groups before, during, and after the procedure., Conclusions: Compared with air, CO2 insufflation during colonoscopy reduced postcolonoscopy abdominal discomfort and improved patients' satisfaction. It was safe to use CO2 insufflation in deeply sedated colonoscopy., (© 2015 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background and Aims: Endoscopic submucosal dissection (ESD) is commonly performed under air insufflation and is often accompanied by abdominal discomfort. CO2 is absorbed more rapidly by the body than is air; however, the use of CO2 insufflation in ESD remains controversial. This randomized, double-blind, controlled, prospective study was designed to assess the efficacy of CO2 versus air insufflation in gastric ESD., Methods: Between May 2012 and August 2014, a total of 110 patients with gastric tumors were randomly assigned to the CO2 insufflation (CO2 group, n = 54) or air insufflation group (air group, n = 56). Abdominal pain after ESD was chronologically recorded via visual analog scale (VAS) scores. Secondary outcome measurements were adverse events, abdominal circumference, amount of sedatives prescribed, and use of analgesics., Results: Neither the baseline patient characteristics nor the mean procedural time differed between the groups. The VAS score for abdominal pain was 35.2 in the CO2 insufflation group versus 48.5 in the air insufflation group 1 hour after ESD (P = .026), 27.8 versus 42.5 three hours after ESD (P = .007), 18.4 versus 34.8 six hours after ESD (P = .001), and 9.2 versus 21.9 one day after ESD (P < .001). Changes in abdominal circumference, the amounts of sedative drugs taken, and the adverse events did not differ between the groups. However, the air insufflation group required more analgesics than did the CO2 insufflation group (CO2 group, 22.0% [11/50]; air group, 42.3% [22/52]; P = .028)., Conclusions: CO2 insufflation during gastric ESD significantly reduced abdominal pain and analgesic usage compared with air insufflation. (, Clinical Trial Registration Number: NCT01579071.), (Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Aim: Therapeutic endoscopic retrograde cholangiopancreatography (ERCP) tends to require considerable air insufflation, which results in abdominal pain or distension. We investigated the efficacy of carbon dioxide (CO2 ) compared with air insufflation when using two different sedation protocols in therapeutic ERCP., Methods: Patients who required therapeutic ERCP were randomly assigned to four groups based on preliminary data: air insufflation with balanced propofol sedation (BPS), air with propofol + opioid sedation (PS), CO2 with BPS, and CO2 with PS. Post-ERCP abdominal pain, distension and nausea by the 10-point visual analogue scale (VAS), and gas volume score (GVS) by the four-point ordinal scale were measured according to the time interval. Overall satisfaction with sedation, sedation efficacy, and complications were also measured., Results: The CO2 with BPS group showed lowest mean VAS score for abdominal pain (immediately after recovery, P = 0.002; and 3 h post-ERCP, P = 0.047) and distension (immediately after recovery, P = 0.018; 3 h post-ERCP, P < 0.01; and 24 h post-ERCP, P = 0.042). Overall satisfaction with sedation was greater in the CO2 with BPS group (P = 0.005). Mean GVS at 2 h and 12 h post-ERCP was significantly lower in the CO2 with BPS group (P < 0.05). There were no significant differences in procedure or sedation-related complications., Conclusion: CO2 with BPS showed the lowest VAS score for early abdominal pain, distension and GVS, and had a higher score for overall satisfaction for sedation., (© 2015 The Authors. Digestive Endoscopy © 2015 Japan Gastroenterological Endoscopy Society.)

Background and Study Aims: Compared with air insufflation, water exchange and carbon dioxide (CO2) insufflation have been shown to reduce colonoscopy discomfort; however, head-to-head studies of the two methods are lacking. We aimed to compare water exchange and CO2 insufflation directly with regard to pain during primary unsedated colonoscopy., Methods: Patients willing to undergo unsedated colonoscopy at three centers in Norway and Poland were randomized 1:1 to water exchange or CO2 insufflation during colonoscope insertion. Patients were blinded to group allocation. The primary end point was the proportion of patients reporting moderate or severe procedural pain on a 4-point verbal rating scale (VRS-4) at discharge. Secondary outcomes included the proportion of patients reporting no pain on the VRS-4., Results: A total of 473 patients were randomized. A discharge pain questionnaire was completed by 226 of 234 patients (97 %) in the water exchange group versus 226 of 239 patients (95 %) in the CO2 group (P = 0.37). Moderate or severe pain was reported by 47 of 226 patients (21 %) in the water exchange group versus 60 of 226 patients (27 %) in the CO2 group (P = 0.15). No pain was reported by 100 of 226 patients (44 %) and 69 of 226 patients (31 %) in the water exchange and CO2 groups, respectively (P = 0.003). On-demand sedation was used in 15 patients (6 %) in each group (P = 0.95)., Conclusions: There was no significant reduction in moderate or severe pain in a comparison of water exchange with CO2 insufflation. The secondary outcome of no pain was significantly more frequent in the water exchange group. Clinical trials registry number: NCT01633333., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective: Residual carbon dioxide contributes substantially to pain following laparoscopic surgery. We evaluated the effects of extended assisted ventilation (EAV) with an open umbilical trocar valve for five additional minutes following laparoscopic hysterectomy on postoperative abdominal and shoulder pain levels. We also examined whether a combination of EAV and trocar site infiltration (TSI) with lidocaine could further reduce postoperative pain levels., Study Design: In this prospective randomized trial, the effectiveness of EAV and EAV/TSI in reducing postoperative abdominal and shoulder pain were compared with that of a standard treatment regime in 283 patients undergoing laparoscopic hysterectomy (total or supracervical). Pain levels were evaluated by self-assessment questionnaire using a numeric rating scale (NRS) and by postoperative piritramid requirement, a surrogate parameter for postoperative analgesic drug requirement. The incidence of nausea and vomiting was also assessed., Results: Compared with the standard treatment regime, EAV reduced abdominal pain levels significantly at 3h (NRS score, 3.21 ± 1.56 vs. 4.73 ± 1.71) and 24h (3.82 ± 1.49 vs. 4.95 ± 1.68) postoperatively (both p < 0.01). EAV also significantly reduced shoulder pain at 24h (EAV vs. control, 4.28 ± 1.51 vs. 5.14 ± 1.49) and 48 h (3.64 ± 1.66 vs. 4.22 ± 1.43) postoperatively (both p < 0.01). Patients in the EAV group had significantly lower piritramid requirements compared with standard treatment at 3h post-operatively (4.28 ± 2.09 mg vs. 6.31 ± 2.21 mg; p<0.01). EAV/TSI showed no additional benefit in terms of pain reduction compared with EAV alone. Incidences of postoperative nausea and vomiting were not reduced by EAV or EAV/TSI., Conclusion: EAV was found to be an effective and safe method to reduce postoperative pain levels in patients undergoing laparoscopic hysterectomy., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Objectives: The role of carbon dioxide (CO2) insufflation during endoscopic retrograde cholangiopancreatography (ERCP) is debated. A meta-analysis was performed to evaluate the efficacy and safety of CO2 insufflation for ERCP., Methods: Searches were conducted in multiple databases composed of Pub-Medline, EMBASE, the Cochrane Library, science citation index expanded, Google scholar, and CNKI China series full-text database. Outcome measurements are listed below: ERCP procedural data, post-ERCP abdominal discomfort, radiographic evaluation of bowel gas volume, and CO2 safety data concerning CO2 elimination., Results: Seven published randomized clinical trials involving 756 patients fulfilling the inclusion criteria were selected for meta-analysis, almost all of high quality. The incidence of ERCP-related complications was reduced by CO2 insufflation, so were the events of 1-hour, 3-hour, and 6-hour post-ERCP abdominal pain, based on their corresponding statistical results. Besides, CO2 insufflation was associated with less gas volume in the bowel lumen after the procedure. There were no significant differences between CO2 and air insufflation in total procedure time, the success rate of selective cannulation, post-ERCP abdominal distension, respectively. Subsequent sensitivity and subgroup analyses produced conflicting results., Conclusions: Compared with air insufflation, CO2 insufflation during ERCP reduces post-ERCP abdominal pain, post-ERCP bowel remnant gas volume, and ERCP-related complications, without clinically significant systematic CO2 retention.

Aim: To determine if carbon dioxide (CO₂), insufflated during colonoscopy reduces pain experienced by patients post colonoscopy compared to air., Method: A randomised, double-blinded, controlled trial with 205 consecutive consented patients referred for elective colonoscopy was undertaken at MidCentral Health Gastroenterology Department. Patients were randomised to colonic insufflation with either air or CO₂. A comparison of reported pain was undertaken using a 0-10 point numeric rating scale at several time periods; intra procedure, 10, 30, and 60 minutes post procedure. In addition groups were compared on the proportion of participants reporting 0 pain levels at each of the same time periods., Results: CO₂ insufflation was provided to 108 patients and air to 97 patients. No differences in mean pain scores or the proportion of those who report zero pain were found between the groups intra procedure. However, those who received CO₂ insufflation were found to have significantly lower mean pain scores (p<0.001) and to have a significantly greater proportion of persons reporting 0 pain scores (p<0.001) at all three observation times post procedure than those who received air., Conclusion: Those receiving CO₂ during colonoscopy experienced less post colonoscopy pain than those who received air insufflation. Carbon dioxide should be considered as the insufflating gas during colonoscopy.

Aim: To assess the safety and efficacy of carbon dioxide (CO(2)) insufflation during endoscopic retrograde cholangiopancreatography (ERCP)., Methods: The Cochrane Library, Medical Literature Analysis and Retrieval System Online, Excerpta Medica Database, Science Citation Index Expanded, Chinese Biomedical Literature Database, and references in relevant publications were searched up to December 2011 to identify randomized controlled trials (RCTs) comparing CO(2) insufflation with air insufflation during ERCP. The trials were included in the review irrespective of sample size, publication status, or language. Study selection and data extraction were performed by two independent authors. The meta-analysis was performed using Review Manager 5.1.6. A random-effects model was used to analyze various outcomes. Sensitivity and subgroup analyses were performed if necessary., Results: Seven double-blind RCTs involving a total of 818 patients were identified that compared CO(2) insufflation (n = 404) with air insufflation (n = 401) during ERCP. There were a total of 13 post-randomization dropouts in four RCTs. Six RCTs had a high risk of bias and one had a low risk of bias. None of the RCTs reported any severe gas-related adverse events in either group. A meta-analysis of 5 RCTs (n = 459) indicated that patients in the CO(2) insufflation group had less post-ERCP abdominal pain and distension for at least 1 h compared with patients in the air insufflation group. There were no significant differences in mild cardiopulmonary complications [risk ratio (RR) = 0.43, 95% CI: 0.07-2.66, P = 0.36], cardiopulmonary (e.g., blood CO(2) level) changes [standardized mean difference (SMD) = -0.97, 95% CI: -2.58-0.63, P = 0.23], cost analysis (mean difference = 3.14, 95% CI: -14.57-20.85, P = 0.73), and total procedure time (SMD = -0.05, 95% CI: -0.26-0.17, P = 0.67) between the two groups., Conclusion: CO(2) insufflation during ERCP appears to be safe and reduces post-ERCP abdominal pain and discomfort.

Background and Aim: Colonoscopy has the disadvantage of pain and discomfort for patients. It has been shown in randomized controlled trials that carbon dioxide (CO(2) ) insufflations significantly reduce pain and discomfort in patients undergoing colonoscopy. However, there have been no studies in which CO(2) insufflation in colonoscopy of patients with irritable bowel syndrome (IBS) was investigated., Methods: Randomized double-blind controlled study was conducted to assess the suffering from colonoscopy in patients with IBS and the efficacy of CO(2) insufflation in colonoscopy for patients with IBS. Patients with IBS and controls who received colonoscopy were randomized into an air or CO(2) insufflation group. Patients' symptoms such as distension and pain were compared using a 10-cm visual analog scale (VAS)., Results: There were 18 patients in the IBS/air group, 19 patients in the IBS/CO(2) group, 25 patients in the control/air group and 26 patients in the control/CO(2) group. The mean value of severity of distension after colonoscopy and the mean value of severity of pain from during examination to one hour after the examination were higher in the IBS group than in the control group. The severity of these symptoms was reduced earlier in the CO(2) group. CO(2) insufflation in colonoscopy was more effective in the IBS group than in the control group from 15 min to one hour after the examination., Conclusion: Regarding colonoscopy-related suffering, IBS patients showed significant differences from non-IBS patients. CO(2) insufflation in colonoscopy is effective for IBS patients, particularly for patients who commence activities after colonscopy., (© 2012 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Background: Pain and bloating following colonoscopy are an underestimated problem, with 30 - 60 % of patients complaining of such symptoms. The use of CO₂ has been shown to significantly decrease pain after colonoscopy in academic hospital-based studies. The aim of the present study was to evaluate whether such an effect can also be seen during private practice routine colonoscopy., Patients and Methods: In a prospective double-blind randomized trial, one experienced colonoscopist (> 12,000 examinations) used either air or CO₂ insufflation for diagnostic or screening colonoscopy in consecutive patients presenting for diagnostic and screening colonoscopy in private practice. Outcome parameters were occurrence and duration of pain and bloating after colonoscopy based on a patient questionnaire., Results: Of 180 randomized patients, 156 replies were analyzed (43.3 % male, mean age 61.7 ± 9.7 years). There were no significant differences between the two groups with respect to age and sex distribution, indication, sedation, examination times and polypectomy rates. Both pain and abdominal bloating were significantly lower in the CO₂ group. Abdominal pain and bloating in the CO₂ vs. air group were absent in 84.4 vs. 64.6 % (p = 0.005) and 66.2 vs. 32.9 % (p < 0.001). Moderate/strong symptoms were also significantly lower with CO₂., Conclusions: The use of CO₂ appears to be as effective in daily routine in private practice colonoscopy as reported in previous hospital-based studies., (© Georg Thieme Verlag KG Stuttgart · New York.)

Introduction: insufflation with carbon dioxide (CO2) during endoscopies compared to air is associated with a decrease in abdominal discomfort after the examination, because CO2 is readily absorbed through the small intestine and eliminated by the lungs., Aim: the objective of this randomized clinical trial was to assess the effect of CO2 insufflation on pain and abdominal distension after an ileo-colonoscopy (I) and after an ileo-colonoscopy plus gastroscopy (I+G)., Material and Methods: we included a total of 309 patients in the study and all endoscopies were performed under sedation with propofol. Two hundred fourteen patients underwent an I (132 with CO2 / 82 with air) and 95 underwent an I+G (53 with CO2 / 42 with air). Abdominal pain was studied at 10, 30 and 120 minutes of exploration and abdominal perimeter difference before and after the procedure., Results: both in group I and in group I+G, the use of CO2 translated into an average of abdominal pain significantly lower (p < 0.05). Similarly, a smaller increase in waist circumference was found among group I and group I+G, in patients where CO2 was used (p < 0.05)., Conclusion: the insufflation of CO2 instead of air during the performance of endoscopy significantly reduces the discomfort and abdominal pain after an ileo-colonoscopy and after a gastroscopy + ileo-colonoscopy.

Background: Endoscopic retrograde cholangiopancreatography (ERCP) and related procedures can cause abdominal pain and discomfort. Two clinical trials have indicated, using the visual analogue scale (VAS) score, that CO(2) insufflation during ERCP ameliorates the suffering of patients without complications, compared with air insufflation. However, differences in patient suffering between CO(2) and air insufflation after ERCP under deep conscious sedation have not been reported. We focused on the gas volume score (GVS) as an objective indicator of gas volume, and designed a multicenter, prospective, double-blind, randomized, controlled study with CO(2) and air insufflation during ERCP., Methods: Between March 2010 and August 2010, 80 patients who required ERCP were enrolled and evenly randomized to receive CO(2) insufflation (CO(2) group) or air insufflation (air group). ERCP and related procedures were performed under deep conscious sedation with fentanyl citrate or pethidine and midazolam or diazepam. The GVS was evaluated as the primary endpoint in addition to the VAS score as the secondary endpoint., Results: The GVS after ERCP and related procedures in the CO(2) group was significantly lower than that in the air group (0.14 ± 0.06 vs. 0.31 ± 0.11, P < 0.01), as well as the rate of increase in GVS ([GVS after - GVS before]/[GVS before ERCP and related procedures] × 100) (3.8 ± 5.9 vs. 21 ± 11.1%, P < 0.01). VAS scores 3 and 24 h after ERCP and related procedures were comparable between the CO(2) and air groups for abdominal pain, abdominal distension, and nausea. Additionally, VAS scores were not correlated with the GVS., Conclusions: CO(2) insufflation during ERCP reduces GVS (bowel gas volume) but not the VAS score of suffering compared with air insufflation. Deep and sufficient sedation during ERCP and related procedures is important for the palliation of patients' pain and discomfort.

Aim: The aim of this paper was to evaluate the effect of carbon dioxide (CO2) vs. air insufflation on post-endoscopic retrograde cholangiopancreatography (ERCP) abdominal pain and distension. In addition, we investigated the changes in the partial pressure of end-tidal CO2 (PetCO2) and the partial pressure of arterial CO2 (PaCO2)., Methods: From October 2009 to January 2010, all patients admitted to our centre for ERCP were screened for enrollment; the patients recruited were randomised to CO2 or air insufflation. The patients were asked to rate their abdominal pain intensity and distension using a 100-mm Visual Analogue Scale (VAS) before, in the recovery room and at 1, 3, 6 and 24 hours after the ERCP. All anesthesiological and endoscopic details and complications were evaluated., Results: We included 76 patients, 39 in the Air group and 37 in the CO2 group. The groups were similar for age, gender, indications and duration of the procedure. Post-procedure mean values of pain (in the recovery room and at 1, 3 and 6 hours) and distension (at recovery room, and at 1 and 3 hours) according to the VAS were significantly reduced in the CO2 group as compared to the Air group. At baseline, the PetCO2 values were similar between the two groups while, during the ERCP, they increased significantly in CO2 group as compared to the Air group; these values were reduced by simply increasing the ventilation., Conclusion: CO2 insufflation during ERCP significantly reduces post-procedural abdominal pain and distension. Increased PetCO2 and PaCO2 values remained within acceptable or readily controllable ranges.

Background: Insufflation with carbon dioxide (CO(2)) in colonoscopy has not been widely adopted and, consequently, limited data are available on insufflated gas volume and blood pCO(2). The aim of this study was to compare CO(2) and air as an insufflation agent in patients undergoing colonoscopy without sedation in terms of insufflated gas volume, pCO(2), pain and examination time., Methods: This was a randomized, double-blind, control trial. Consecutive patients presenting for colonoscopy, excluding those with lung or malignant disease, were randomized into two groups: insufflation with air or with CO(2), respectively. Insufflated gas volume, pain, pCO(2) and examination time were assessed., Results: The study cohort comprised 120 patients (66 randomized to CO(2) group). No significant difference in insufflated gas volumes was found between the CO(2) and air groups. The mean pCO(2) measured before, during (the peak value) and 30 min after colonoscopy were 40, 43 and 40 mmHg, respectively, in both groups. The pain scores in the air group were significantly greater than those in the CO(2) group until 3 h after the examination. There was a significant faster cecal intubation time and a trend toward shorter examination time in the CO(2) group., Conclusions: The CO(2) gas volume used in our study (14.0 L) was much greater than that reported by others (8.3 L), but the pCO(2) values were still within the normal reference range, indicating the safety of CO(2) insufflation over a greater range of CO(2) gas volume. Among our patients, CO(2) insufflation was associated with relatively less pain and a shorter examination time. Based on our results, we recommend that CO(2) become the standard gas for insufflation in patients undergoing colonoscopy without sedation.

Aim: To clarify the effectiveness of CO(2) insufflation in potentially difficult colonoscopy cases, particularly in relation to the experience level of colonoscopists., Methods: One hundred twenty potentially difficult cases were included in this study, which involved females with a low body mass index and patients with earlier abdominal and/or pelvic open surgery or previously diagnosed left-side colon diverticulosis. Patients receiving colonoscopy examinations without sedation using a pediatric variable-stiffness colonoscope were divided into two groups based on either CO(2) or standard air insufflation. Both insufflation procedures were also evaluated according to the experience level of the respective colonoscopists who were divided into an experienced colonoscopist (EC) group and a less experienced colonoscopist (LEC) group. Study measurements included a 100-mm visual analogue scale (VAS) for patient pain during and after colonoscopy examinations, in addition to insertion to the cecum and withdrawal times., Results: Examination times did not differ, however, VAS scores in the CO(2) group were significantly better than in the air group (P < 0.001, two-way ANOVA) from immediately after the procedure and up to 2 h later. There were no significant differences between either insufflation method in the EC group (P = 0.29), however, VAS scores for CO(2) insufflation were significantly better than air insufflation in the LEC group (P = 0.023) immediately after colonoscopies and up to 4 h afterwards., Conclusion: CO(2) insufflation reduced patient pain after colonoscopy in potentially difficult cases when performed by LECs., (2009 The WJG Press and Baishideng. All rights reserved.)

Objective: To assess the safety and efficacy of carbon dioxide (CO(2)) in colonoscopy examination., Methods: We randomized 349 patients to undergo colonoscopy with insufflation of air (n=175) or CO(2) (n=174). At colonoscopy, p (ET CO(2)) was observed at 4 time points: before the exam, arrived caecum, back rectum, and after the exam. Patient's experience of pain in the end and after the examination at 1, 3, 6, and 24 h was registered using a visual analog scale (VAS). Sedation was not used routinely., Results: The groups were similar in age, sex, inspection time, and caecal intubation rate (all P>0.05). There were no significant differences in p (ET CO(2)) values between the 2 groups before and after the procedure (all P>0.05). VAS scores in the CO(2) group at various time points after the examination were significantly lower than those in the air group (all P<0.05). The percent of VAS scores of 0 in the CO(2) group after 1, 3, 6, and 24 h was significantly higher than that in the air group (all P<0.01)., Conclusion: Injection of CO(2) for colonoscopy will not cause CO(2) retention, and it may significantly reduce the pain, which is safe and effective.

Introduction: Air insufflation during colonoscopy is considered the standard method in most endoscopic centers. Notably, several studies have reported reduced abdominal pain after colonoscopy with CO2 insufflation in unsedated and in lightly sedated patients. The present study was designed to assess the efficacy of CO2 insufflation after colonoscopy in moderately and deeply sedated patients. We also evaluated whether CO2 insufflation increases patients' compliance for colorectal cancer screening., Patients and Methods: A total of 300 consecutive patients allocated to colonoscopy were randomly assigned to either CO2 or air insufflation. Propofol was titrated to a level of deep sedation and propofol combined with midazolam was used for moderate sedation. Post-interventional pain levels and satisfaction with the procedure were registered on a 10-point visual analog scale. Compliance for colorectal cancer screening was ascertained separately., Results: CO2 insufflation was used during colonoscopy in 157 patients; conventional air was used in 143 patients. The two groups were comparable with regard to age, sex and body mass index. Neither major nor minor complications were observed. Pain sensation was significantly lower in the CO2 group at 15 min, 30 min and 6 h after colonoscopy (P<0.01); at 12 h no difference was observed. In contrast, levels of patient satisfaction did not show any significant difference. Voluntary colorectal cancer screening appeared not to be influenced by the type of insufflation gas used., Conclusions: CO2 insufflation in deeply and moderately sedated patients during colonoscopy has no impact on patients' satisfaction with the procedure or on their attitude to voluntary colorectal cancer screening. However, the use of CO2 insufflation significantly diminishes abdominal pain after colonoscopy.

Background and Study Aims: The effect on abdominal pain of using carbon dioxide (CO2) for insufflation during endoscopic retrograde cholangiopancreatography (ERCP) has not been investigated. The present study aimed to compare CO2 insufflation with standard air insufflation with respect to the pain experienced during and after ERCP. In addition, we investigated the effect of CO2 insufflation on the partial pressure of CO2 (Pco2)., Patients and Methods: A total of 118 consecutive patients who were undergoing ERCP were randomized to CO2 insufflation or to air insufflation during the procedure. Both the endoscopists and the patients were blinded with regard to the gas used. Patients rated the intensity of pain experienced on a 100-mm visual analogue scale (VAS) during ERCP and at 1 hour, 3 hours, 6 hours, and 24 hours after the procedure. Transdermal Pco2 was measured continuously in all patients during the procedure., Results: Altogether, 116 patients were eligible for analysis, 58 in each treatment group, and 91 patients responded to the questionnaire (78 %). The mean severity of postprocedure pain was significantly reduced in the CO2 group compared with the air group at 1 hour (5 mm vs. 19 mm on the VAS, P < 0.001), at 3 hours (7 mm vs. 21 mm, P < 0.001), at 6 hours (10 mm vs. 22 mm, P = 0.006), and at 24 hours (4 mm vs. 20 mm, P < 0.001) after the procedure. Radiographs taken 5 minutes after the procedure showed that abdominal distension was more pronounced in patients in the air insufflation group. There were no differences in Pco2values between the two treatment groups., Conclusions: Carbon dioxide insufflation during ERCP significantly reduces postprocedural abdominal pain. No side effects were observed. Carbon dioxide should be the standard gas used for insufflation in ERCP.

Objective: To evaluate satisfaction rate, efficacy and complication rate of carbon dioxide (CO2) vs normal saline as uterine distension medium for outpatient diagnostic hysteroscopy in patients with suspicious endometrial cancer., Methods: Thirty-eight undergoing outpatient hysteroscopy performed with carbon dioxide (group A) or normal saline (group B). Quality of vision of uterine cavity, procedure time, complications, patient discomfort, satisfaction rate have been evaluated., Results: In group B a significant reduction in abdominal pain, shoulder tip pain and a lower incidence of vasovagal reactions were observed in comparison to group A. In normal saline group we found a higher satisfaction rate and a lower operative time in comparison to the CO2 group., Conclusions: Uterine distension with normal saline seems to have less adverse effects and is better accepted by patients.

Introduction: Insufflation of air is a cause of discomfort during and after colonoscopy. Although this can be minimized by good technique, the use of carbon dioxide insufflation may provide further benefits. Carbon dioxide is rapidly absorbed and excreted through the lungs. We hypothesized that carbon dioxide would alleviate post-colonoscopy discomfort., Methods: After they had provided informed consent, patients presenting for colonoscopy were randomized into two groups: those in whom air was used for colonoscopy and those in whom carbon dioxide was used. Pain during and ten minutes after colonoscopy was measured on a ten-point analog scale. Data are mean and 95 percent confidence limits., Results: There were 124 patients in the air group and 123 in the carbon dioxide group. Age, body mass index, indication, diagnosis, and number of procedures were similar for the two groups. There were no differences between the groups in the amounts of sedation or analgesia used, the percentage of examinations that were complete (air, 98.4 percent; carbon dioxide, 95.2 percent), or patient satisfaction (on a scale of 1 to 10: air, 9.4; carbon dioxide, 9.5). Although there were more females in the carbon dioxide group (69 vs. 51), hysterectomy rates were the same. Pain scores (mean +/- 95 percent confidence interval; scale of 1 to 10) immediately after the examination were 4.3 +/- 0.3 for air and 3.6 +/- 0.3 for carbon dioxide (no significant difference). Pain scores 10 minutes later were 2.1 +/- 0.2 for air and 0.9 +/- 0.2 for carbon dioxide (P < 0.05, Student's t-test)., Conclusion: Because there was significantly less abdominal pain ten minutes after colonoscopy in the group in whom carbon dioxide was used, carbon dioxide should be considered as an insufflating gas for colonoscopy.

Background: Abdominal pain after colonoscopy is a common, distressing symptom resulting from bowel distension by insufflated gas. CO(2), unlike air, is rapidly cleared from the colon by passive absorption. A commercially available CO(2) delivery system has only recently become available. The effects of CO(2) and air insufflation on residual bowel gas and postprocedure pain were compared., Methods: One hundred patients were randomized to undergo colonoscopy with insufflation of air (n = 51) or CO(2) (n = 49) by means of a regulator; 97 patients completed the study. Patients with active GI bleeding, inflammatory bowel disease, or previous colectomy were excluded. Pain scores (ordinal scale: 0 = none, to 5 = extreme) were recorded immediately after colonoscopy and at 1, 6, and 24 hours. Residual colonic gas was evaluated on abdominal radiographs at 1 hour., Results: Residual colonic gas and postprocedural pain at 1 and 6 hours were significantly less in the CO(2) group. 71% of patients insufflated with room air had colonic distension in excess of 6 cm versus 4% for those in the CO(2) group. 94% of patients insufflated with CO(2) had minimal colonic gas versus 2% in whom air was used (p < 0.0001). Of patients insufflated with air, 45% and 31% had pain at, respectively, 1 hour and 6 hours, versus 7% and 9%, respectively, for those insufflated with CO(2) (respectively, p < 0.0001 and p < O.02). No complications resulted from use of the CO(2) delivery system., Conclusions: Insufflation of CO(2) rather than air significantly reduces abdominal pain and bowel distension after colonoscopy. CO(2) may be insufflated safely and effectively with the new CO(2) delivery system.

Purpose: The aim of the study was to evaluate the efficacy of a double-contrast barium enema (DCBE) with CO(2) as a distending gas after a screening flexible sigmoidoscopy for reducing abdominal distension after an examination., Patients and Methods: A total of 165 DCBEs for patients with positive faecal occult blood tests were randomly allocated to a CO(2) group (n = 83) and a control group (n = 82) using air. Abdominal radiograph were taken before the DCBE, immediately following it, and 30 minutes later to determine residual bowel gas. The degree of abdominal discomfort was recorded using a scoring system., Results: The patients in the CO(2) group had significantly smaller amounts of residual gas 30 minutes after the DCBE than did the control group, both in the colon (P < 0.02) and in the small intestine (P < 0.001). There was significantly less abdominal distension after the DCBE in the CO(2) group compared to the control group (P < 0.001). The abdominal discomfort score at 30 minutes after CO(2) correlated with the residual gas in the small intestine (r = 0.390,P = 0.003) but not in the colon (r = 0.155, P = 0.15). The quality of the images and the number of polyps detected did not differ between two groups., Conclusions: We concluded that using CO(2) when administering a DCBE after a screening sigmoidoscopy was useful for relieving abdominal discomfort following the examination; furthermore, it did not impair the diagnostic ability of the DCBE., (Copyright 2002 The Royal College of Radiologists.)

Background: Helium is an inert gas that, if used for insufflation during laparoscopy, may be followed by less postoperative pain than carbon dioxide (CO2) insufflation, due to a more limited effect on intraabdominal pH and metabolism. Saline lavage has also recently been shown to reduce postoperative pain following laparoscopic surgery. To evaluate these possibilities and to better define the clinical safety of helium insufflation, we undertook a prospective randomized trial comparing CO2 and helium insufflation with or without saline lavage in patients undergoing elective laparoscopic upper abdominal surgery., Methods: From January to November 2000, 173 patients undergoing elective laparoscopic cholecystectomy or fundoplication were randomized to undergo laparoscopy with either CO2 or helium insufflation. Within each group, patients were further randomized to undergo peritoneal lavage with 2 L of 0.9% saline at the end of the surgical procedure. This yielded the following four patient groups; CO2 (group 1, n = 47), CO2 + saline lavage (group 2, n = 43), helium (group 3, n = 43) and helium + saline lavage (group 4, n = 40). Patients were blinded to their randomization, and post-operative assessment was also performed by a blinded investigator, who applied a standardized scoring system to assess postoperative pain., Results: The study groups were well matched for age, sex, weight, American Society of Anesthesiologists (ASA) status, duration of surgery, and volume of gas utilized, and 81% of patients were discharged within 48 h. There were no differences in the incidence of postoperative complications among the study groups, and postoperative pain scores were not significantly different when all four groups were compared. When helium (groups 3 and 4) was compared with CO2 (groups 1 and 2), no differences in pain score were seen. When no lavage (groups 1 and 3) was compared with lavage (groups 2 and 4), less pain was found in the group undergoing saline peritoneal lavage (mean 4-h pain score, 5.9 vs 5.2; 24-h pain score, 4.8 vs 4.1; p > 0.05)., Conclusions: The use of helium insufflation for laparoscopic surgery, while not associated with any significant adverse sequelae, was not associated with less postoperative pain in this trial. The use of saline peritoneal lavage was associated with less pain in the early postoperative period.

Air has been traditionally used as the negative contrast agent in double contrast barium enema (DCBE) examinations, but causes abdominal pain in the 24 h following the procedure. The frequency of post-procedural pain is less when carbon dioxide (CO2) is used as the negative contrast agent. We evaluated patients following DCBE examinations (using either air or CO2) by means of a questionnaire, to determine whether active drainage of gas altered the post-procedural pain. There was no difference in the pain experienced in the groups receiving CO2 with either active or passive drainage, or in the group receiving air with active drainage. Compared with the other groups there was a significantly higher incidence and severity of pain in the group receiving air and passive drainage. We conclude that active drainage of air following a DCBE examination is as effective as using CO2 in reducing post-procedural pain and swelling.