7026 Double blind randomised controlled trial comparing carbon dioxide and air insufflation during colonoscopy; assessing patient bloating, discomfort and satisfaction.

Background and aims: Adequate visualization during endoscopic retrograde cholangiopancreatography (ERCP) procedure requires distention of the bowel lumen, usually insufflated with room air. Patients often complain of abdominal pain post-procedure. The use of carbon dioxide insufflation in colonoscopy has been shownto result in less post-procedure abdominal pain and distension. Recently, it has been reported the use of carbon dioxide (CO2) insufflation during ERCP procedure is similarly helpful. The purpose of this study was to evaluate the efficiency, safety and comfort of ERCP involving carbon dioxide insufflation through a meta-analysis of published randomized control trials. Methods: Databases including PubMed, EMBASE, the Cochrane Library, the Science Citation Index and momentous meeting abstracts were searched and evaluated by two reviewers independently. Results: Five randomized control trials involving 446 patients were analyzed. Meta-analysis showed that patientsin the CO2 insufflation group had lower pain score (VAS) at 1-hour [MD -12.37, 95%CI(-20.96,-3.78)], 3-hours [MD -9.81, 95%CI (-17.05, -2.57)) and 6-hours [MD -8.78, 95%CI (-13.71, -3.85)] compared with air insufflation group after procedure. However, there were no significant differences between the two groups regardingtotal procedure time and procedure complication. Conclusions: Insufflation with carbon dioxide during ERCP may decrease post-procedure abdominal discomfort without any additional adverse reactions. Thus, CO2 insufflation seems appropriate to use during ERCP procedure. Large trials are required to prove any additional advantages to carbon dioxide insufflation during ERCP.

Background: Flexible sigmoidoscopy is currently recommended as a screening modality for colorectal cancer. However, a substantial number of patients experience discomfort because of the procedure, possibly limiting compliance and thus screening success. During endoscopy, air is commonly used to insufflate the bowel. Carbon dioxide rather than air insufflation has been shown to reduce procedurerelated pain and discomfort in colonoscopy. The aim of the present study was to evaluate whether carbon dioxide insufflation reduces discomfort during and after flexible sigmoidoscopy for colorectal cancer screening. Methods: In a randomized, double-blinded design, 230 consecutive participants in a population-based flexible sigmoidoscopy colorectal cancer screening trial were assigned to have their examination performed with either carbon dioxide or air insufflation. Patients were asked to grade discomfort experienced both during and in the hours after the procedure on a visual analogue scale. Results: Carbon dioxide insufflation significantly reduced the amount of discomfort at 1, 3 and 6 h after the sigmoidoscopy. One hour after the examination, 84% of patients in the CO 2 group reported no discomfort, compared to 64% in the air group ( P = 0.006). No differences between the groups were observed during the examination. Conclusions: Carbon dioxide insufflation significantly reduced postexamination discomfort. The use of carbon dioxide rather than air insufflation may contribute to better public acceptance for flexible sigmoidoscopy screening.

Introduction: Colonoscopy is the gold standard test for prevention of colorectal adenocarcinoma by identifying and removal of adenomas, the pre-cancerous lesion. One of the most common complications from colonoscopy is postprocedural abdominal pain and discomfort due to air insufflation during the procedure. Carbon dioxide(CO2) insufflation has been shown to reduce post procedure crampy abdomen pain due to easy dissolvability in blood and rapid elimination. However the effect of CO2 insufflation on adenoma detection rate(ADR) remained unclear, with studies showing positive and negative effect on ADR. We aimed to do a meta-analysis to identify the effect of CO2 insufflation on ADR when compared to air insufflation by pooling results of individual studies. Methods: Comprehensive literature search was performed in EMBASE, Scopus, Pubmed, Cochrane databases from 1946 to May 31, 2017 to identify potential articles. MeSH headings included in the search included adenoma detection rate, colonoscopy, carbon dioxide insuffl ation. All references from the identified articles were further searched to find more articles. Abstracts published from major gastroenterology meetings were also searched up to May 2017. Studies were included if they compared ADR on cohorts of patients undergoing colonoscopy with CO2 insufflation and air insufflation and had no major differences in baseline characteristics. Odds ratio of ADR was compared between the 2 techniques. Statistics were done using Revman version 5.3 Results: A total of 202 articles were identified from the search strategy and from articles identified through references and abstracts. A total of 4 studies met the inclusion criteria and out of which 3 were published manuscripts and one was abstract. Total number of patients included in the analysis was 3466(2140 in CO2 group, 1326 in air insufflation group). There was no statistically significant difference in ADR between the 2 groups - 1.11 [0.95-1.31](Image 1). However there was significant heterogeneity between the tests, possibly due to low number of studies that qualified for inclusion. Conclusion: CO2 insufflation appears to be non-inferior for adenoma detection when compared to air insufflation. With no disadvantage on ADR with using CO2 insufflation, endoscopy units should adapt the change from air to CO2 insufflation to improve patient experience. Future large randomized trial should be done to study if CO2 insufflation improves ADR when comparing air insufflation.Figure

Safety and Efficacy of Carbon Dioxide (CO2) Insufflation During Endoscopic Submucosal Dissection (ESD) for Gastric Cancer Under Propofol Sedation: A Randomized, Controlled Trial

Background/AimsThis study aimed to compare tolerance to air, carbon dioxide, or water insufflation in patients with anticipated difficult colonoscopy (young, thin, obese individuals, and patients with prior abdominal surgery or irradiation).MethodsPatients with body mass index (BMI) less than 18 kg/m2 or more than 30 kg/m2, or who had undergone previous abdominal or pelvic surgeries were randomized to air, carbon dioxide, or water insufflation during colonoscopy. The primary endpoint was cecal intubation with mild pain (less than 5 on visual analogue scale [VAS]), without use of sedation.ResultsThe primary end point was achieved in 32.7%, 43.8%, and 84.9% of cases with air, carbon dioxide and water insufflation (P<0.001). The mean pain scores were 5.17, 4.72, and 3.93 on the VAS for air, carbon dioxide, and water insufflation (P<0.001). The cecal intubation rate or procedure time did not differ significantly between the 3 groups.ConclusionsWater insufflation was superior to air or carbon dioxide for pain tolerance. This was seen in the subgroups with BMI <18 kg/m2 and the post-surgical group, but not in the group with BMI >30 kg/m2.

Carbon dioxide insufflation during withdrawal of the colonoscope improved postprocedure discomfort: A prospective, randomized, controlled trial

To compare the impact of carbon dioxide (CO₂) and air insufflation on patient tolerance/safety in deeply sedated patients undergoing colonoscopy. Patients referred for colonoscopy were randomized to receive either CO₂ or air insufflation during the procedure. Both the colonoscopist and patient were blinded to the type of gas used. During the procedure, insertion and withdrawal times, caecal intubation rates, total sedation given and capnography readings were recorded. The level of sedation and magnitude of patient discomfort during the procedure was assessed by a nurse using a visual analogue scale (VAS) (0-3). Patients then graded their level of discomfort and abdominal bloating using a similar VAS. Complications during and after the procedure were recorded. A total of 142 patients were randomized with 72 in the air arm and 70 in the CO₂ arm. Mean age between the two study groups were similar. Insertion time to the caecum was quicker in the CO₂ group at 7.3 min vs 9.9 min with air (P = 0.0083). The average withdrawal times were not significantly different between the two groups. Caecal intubation rates were 94.4% and 100% in the air and CO₂ groups respectively (P = 0.012). The level of discomfort assessed by the nurse was 0.69 (air) and 0.39 (CO₂) (P = 0.0155) and by the patient 0.82 (air) and 0.46 (CO₂) (P = 0.0228). The level of abdominal bloating was 0.97 (air) and 0.36 (CO₂) (P = 0.001). Capnography readings trended to be higher in the CO₂ group at the commencement, caecal intubation, and conclusion of the procedure, even though this was not significantly different when compared to readings obtained during air insufflation. There were no complications in both arms. CO₂ insufflation during colonoscopy is more efficacious than air, allowing quicker and better cecal intubation rates. Abdominal discomfort and bloating were significantly less with CO₂ insufflation.

Background and Aims: The safety of carbon dioxide (CO₂) insufflation has not been fully established for esophageal and gastric endoscopic submucosal dissection (ESD) under deep sedation, because CO₂ retention is not only caused by CO₂ insufflation but also by the sedation level and the patient’s respiratory status. To clarify the clinical safety of CO₂ insufflation, we conducted a crossover trial of air and CO₂ insufflations. Methods: A total of 60 patients with early esophageal or gastric cancers underwent ESD during which insufflation was switched from CO₂ to air or from air to CO₂; transcutaneous partial pressure CO₂ (PtcCO₂) was monitored in all patients. We also assessed respiratory function, arterial blood gas analysis, and smoking history. Results: Although significant increases in PtcCO₂ from baseline were observed, there were no significant differences in PtcCO₂ levels during CO₂ insufflation compared with levels during air insufflation in groups that received CO₂ preceding air or air preceding CO₂. All patients underwent ESD safely without adverse events, including 20 patients with subclinical respiratory dysfunction. The sedation protocol was the only significant predictor of CO₂ retention, independent of CO₂ insufflation. Conclusions: CO₂ insufflation can be used as safely as air insufflation during ESD under deep sedation.

A novel method of evaluating corrosive stricture during endoscopy

The increasing demand for colonoscopy has renewed the interest for unsedated procedures. Alternative techniques, such as carbon dioxide insufflation and warm-water infusion, have been advocated to improve patient tolerance for colonoscopy in comparison with air insufflation. The aim of this study was to evaluate the benefits of carbon dioxide insufflation and warm-water irrigation over air insufflation in unsedated patients. This study was a randomized, controlled trial. This study was conducted at a nonacademic single center. Consecutive outpatients agreeing to start colonoscopy without premedication were included. Patients were assigned to either carbon dioxide insufflation, warm-water irrigation, or air insufflation colonoscopy insertion phase. Sedation/analgesia were administered on patient request if significant pain or discomfort occurred. The primary outcome measured was the percentage of patients requiring sedation/analgesia. Pain and tolerance scores were assessed at discharge by using a 100-mm visual analog scale. Three hundred forty-one subjects (115 in the carbon dioxide, 113 in the warm-water, and 113 in the air group) were enrolled. Intention-to-treat analysis showed that the proportion of patients requesting sedation/analgesia during colonoscopy was 15.5% in the carbon dioxide group, 13.2% in the warm-water group, and 25.6% in the air group (p = 0.04 carbon dioxide vs air; p = 0.03 warm water vs air). Median (interquartile range) scores for pain were 30 (10-50), 28 (15-50), and 46 (22-62) in the carbon dioxide, warm-water, and air groups (carbon dioxide vs air, p < 0.01; warm water vs air, p < 0.01); corresponding figures for tolerance were 20 (5-30), 19 (5-36), and 28 (10-50) (carbon dioxide vs air, p < 0.01; warm water vs air, p < 0.01). This investigation was limited because it was a single-center study and the endoscopists were not blinded to randomization. Carbon dioxide insufflation was associated with a decrease in the proportion of patients requesting on-demand sedation, improved patient tolerance, and decreased colonoscopy-related pain in comparison with air insufflation. The findings regarding warm-water irrigation confirmed the previously reported advantages, so that warm-water irrigation and carbon dioxide insufflation could represent competitive strategies for colonoscopy in unsedated patients.

Insufflation of the colon is necessary to distend the lumen for exploration. Carbon dioxide (CO2) insufflation instead of air insufflation (AI) has shown conflicting results about decreasing pain or discomfort during the procedure, even when coupled with water immersion or water exchange method of insertion. CO2 insufflation is associated with a reasonably consistent decrease in bloating and pain scores in the post-procedure period. Other advantages are a decrease in toilet use, less incontinence and less flatulence after colonoscopy. No definitive results are available about the effect of CO2 on the need and dosage of sedation medication(s). Association with water-aided methods appears to show promise in decreasing pain during and after the procedure, achieve higher rates of minimally sedated or unsedated colonoscopy, with less postprocedure bloating and flatulence. Further studies are needed to investigate the impact of combining water-aided methods with CO2 on clinically relevant parameters.

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. 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. 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). 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.

Conventional air insufflation (AI) may cause prolonged abdominal bloating, excessive abdominal pain and discomfort during colonoscopy. Carbon dioxide may be an acceptable alternative to avoid these complications. The object of this study was to evaluate systematically the effectiveness of carbon dioxide insufflation (CI) for colonoscopy compared with AI. Randomized controlled trials (RCTs) comparing the effectiveness of CI with that of AI during colonoscopy were retrieved from medical electronic databases and combined analysis was performed using the RevMan statistical package. The combined outcome of dichotomous and continuous variables was expressed as an odds ratio (OR) and standardized mean difference (SMD). Twenty-one RCTs comprising 3607 patients were included in the study. There was statistically significant heterogeneity among included studies. CI showed a significant trend towards reduced procedural pain [SMD -1.34; 95% confidence interval (95% CI) -2.23 to -0.45; z=2.96; P<0.003] and also postprocedural pain at 1h (SMD -1.11; 95% CI -1.83 to -0.38; z=2.97; P<0.003), 6 and 24h (OR 0.44; 95% CI 0.23-0.85; z=2.44; P<0.01). CI was associated with faster caecal intubation (SMD -0.20; 95% CI -0.37 to -0.02; z=2.23; P<0.03) but the caecal intubation rate was similar (P=0.59) in both colonic insufflation techniques . CI seems to have clinical advantages over AI for colonoscopy with regard to pain during and after the procedure.

A Randomized, Controlled, Double-Blind Trial of Air vs Carbon Dioxide Insufflation During ERCP

Aims:The effect of carbon dioxide (CO2) insufflation and warm-water infusion during colonoscopy on patients with chronic constipation remains unknown. We evaluated CO2 insufflation and warm-water irrigation versus air insufflation in unsedated patients with chronic constipation in China.Patients and Methods:This randomized, single–center, controlled trial enrolled 287 consecutive patients, from January 2014 to January 2015, who underwent colonoscopy for chronic constipation. Patients were randomized to CO2 insufflation, warm-water irrigation and air insufflation colonoscopy insertion phase groups. Pain scores were assessed by the visual analog scale (VAS). The primary outcome was real-time maximum insertion pain, recorded by an unblinded nurse assistant. At discharge, the recalled maximum insertion pain was recorded. Meanwhile, patients were requested to select the VAS at 0, 10, 30, and 60 min after the procedure. In addition, cecal intubation and withdrawal time, total procedure time, and adjunct measures were recorded.Results:A total of 287 patients were randomized. The correlation between real-time and recalled maximum insertion pain ((Pearson coefficient r = 0.929; P < 0.0001) confirmed internal validation of the primary outcome. The mean real-time maximum pain scores during insertion 2.9 ± 2.1 for CO2, 2.7 ± 1.9 for water achieved a significantly lower pain score compared with air (5.7 ± 2.5) group (air vs CO2P < 0.001; air vs water P < 0.001). However, no significant pain score differences were found between the patients in the CO2 and water groups (CO2 vs water, P = 0.0535). P values in painless colonoscopy and only discomfort colonoscopy (pain 1–2) were, respectively, 6 (6.4%) and 8 (8.5%) for air; 17 (17.7%) and 29 (30.2%) for CO2; 16 (16.5%) and 31 (31.9%) for water. At 0, 10, 30, and 60 min postprocedure, pain scores showed in the CO2 and water groups had significantly reduced than in air group. Insertion time was significantly different between air (10.6 ± 2.5) and CO2 (7.2 ± 1.4) (air vs CO2P < 0.001), air and water (6.9 ± 1.3) (air vs water P < 0.001). However, CO2 and was not significantly different in cecum-intubated time (CO2 vs water, P = 0.404). CO2 and water group in extubation time were significantly different, respectively, CO2 (7.9 ± 1.1) and water (8.0 ± 1.1) (CO2 vs water, P = 0.707). CO2 or water group required less implementation of adjunct measures and more willingness to repeat the procedure.Conclusions:Compared with air, the CO2 or water-aided method reduced real-time maximum pain and cecum-intubated time for chronic constipated patients in unsedated colonoscopy. The CO2 insufflation or warm-water irrigation may be a simple and inexpensive way to reduce discomfort in unsedated patients with constipation. This study demonstrated an advantage of using CO2 insufflation and warm-water irrigation during colonoscopy in unsedated constipated patients in China.