Carbon dioxide insufflation attenuates parietal blood flow obstruction in distended colon

Nomogram to predict gas-related complications during transoral endoscopic resection of upper gastrointestinal submucosal lesions

BACKGROUND

Gas-related complications present a potential risk during transoral endoscopic resection of upper gastrointestinal submucosal lesions. Therefore, the identification of risk factors associated with these complications is essential.

AIM

To develop a nomogram to predict risk of gas-related complications following transoral endoscopic resection of the upper gastrointestinal submucosal lesions.

METHODS

We collected patient data from the First Affiliated Hospital of the Army Medical University. Patients were randomly allocated to training and validation cohorts. Risk factors for gas-related complications were identified in the training cohort using univariate and multivariate analyses. We then constructed a nomogram and evaluated its predictive performance based on the area under the curve, decision curve analysis, and Hosmer-Lemeshow tests.

RESULTS

Gas-related complications developed in 39 of 353 patients who underwent transoral endoscopy at our institution. Diabetes, lesion origin, surgical resection method, and surgical duration were incorporated into the final nomogram. The predictive capability of the nomogram was excellent, with area under the curve values of 0.841 and 0.906 for the training and validation cohorts, respectively.

CONCLUSION

The ability of our four-variable nomogram to efficiently predict gas-related complications during transoral endoscopic resection enhanced postoperative assessments and surgical outcomes.

A prospective randomized controlled trial of the safety and efficacy of carbon dioxide insufflation compared with room air insufflation during gastric endoscopic submucosal dissection

BACKGROUND AND AIM

Carbon dioxide (CO₂ ) insufflation during gastric endoscopic submucosal dissection (GESD) under sedation can be used instead of room air insufflation. Appropriate monitoring of the partial pressure of CO₂ during GESD is necessary due to the impaired respiration. The aim of this study was to assess the safety and efficacy of CO₂ insufflation during GESD compared with conventional room air insufflation.

METHODS

Patients with a gastric epithelial neoplasm or early gastric cancer were enrolled. A total of 76 consecutive patients were randomly assigned to the CO₂ insufflation group (CO₂ group) or the room air insufflation group (air group). The primary outcome was the mean difference of end-tidal CO₂ (EtCO₂ ) between two groups.

RESULTS

The upper bound of the 95% CI for the mean EtCO₂ difference between the two groups before the procedure and at 15, 30 and 45 min after insufflation met the criteria for noninferiority. In a subgroup analysis of patients 70 years and older, the mean difference of EtCO₂ was not significantly different between two groups. However, the air group received more analgesics than the CO₂ group after the procedure (67.6% vs 35.1%, P = 0.005). In addition, in terms of improvement of abdominal pain or bowel gas after 24 h of GESD, CO₂ group showed better results than air group (both P < 0.05).

CONCLUSIONS

CO₂ insufflation during GESD is as safe as using room air, and patients, including elderly patients, receiving CO₂ achieve more rapid relief of abdominal pain and intra-abdominal residual gas during and after the procedure.

Colonoscopy-related colonic ischemia

Colonoscopy is a risk factor for colon ischemia. The colon is susceptible to ischemia due to its minor blood flow compared to other abdominal organs; the etiology of colon ischemia after colonoscopy is multifactorial. The causative mechanisms include splanchnic circulation impairment, bowel preparation, drugs used for sedation, bowel wall ischemia due to insufflation/barotrauma, and introduction of the endoscope. Gastroenterologists must be aware of this condition and its risk factors for risk minimization, early diagnosis, and proper treatment.

Efficacy of CO₂ Infusion for Preoperative Computed Tomographic Angiography with Computed Tomographic Colonography

BACKGROUND Computed tomographic colonography (CTC) is useful for patients for whom colonoscopy may be difficult to perform and is widely employed to examine the vasculature prior to colorectal cancer surgery. Computed tomographic angiography (CTA) was shown to be beneficial intraoperatively to manipulate blood vessels and prevent vascular injury. Three-dimensional (3D)-CTA combined with CTC (3D-CTA with CTC) is useful for preoperative evaluations of the anatomy of mesenteric vessels, colon, and lymph nodes. We observed that when the intestine was dilated with carbon dioxide (CO₂), the arteriovenous delineation was often more pronounced than without CO₂. To clarify the effects of gas injection with and without CO₂ on hemodynamics and vascular passage, we compared the effect of contrast for blood vessels. MATERIAL AND METHODS Thirty patients with resectable colorectal cancer who underwent a preoperative CT examination at our institution from January to October 2019 were study participants. Of these, 15 underwent 3D-CTA and 15 had 3D-CTA with CTC. Three board-certified radiologists independently and blindly evaluated 18 blood vessels. CT values for each blood vessel were measured on each image. RESULTS CT values for 3D-CTA with CTC were significantly higher with CO₂ than without CO₂. The quality of 3D-CTA with CTC images for visualization of blood vessels was also significantly greater than that of 3D-CTA, especially those of arterial and intramesenteric venous systems. CONCLUSIONS Based on the higher image quality and CT values obtained by 3D-CTA with CTC for vessels, compared with by 3D-CTA imaging, 3D-CTA with CTC imaging might be useful in evaluating colorectal cancers.

Carbon dioxide versus room air for colonoscopy in deeply sedated pediatric patients: a randomized controlled trial

Background and study aims  Use of carbon dioxide (CO ₂ ) instead of room air (RA) during colonoscopy in adults revealed significantly less flatulence and abdominal pain in several studies. The objectives of this study were to investigate the effects of CO ₂ usage on post-interventional pain, abdominal discomfort, abdominal girth, pCO ₂ levels, and narcotic requirement in deeply sedated pediatric patients. Patients and methods  A total of 97 children and adolescents aged 4 years to 17 years undergoing colonoscopy were randomized to RA or CO ₂ in a prospective, randomized, controlled trial. Age-appropriate pain scales assessed abdominal pain as primary outcome. In addition, abdominal girth, abdominal bloating, transcutaneous pCO ₂ , narcotic requirement to achieve deeply sedation, and post-procedural analgesic demand was analyzed in 73 patients. Results  Overall, significantly fewer patients reported bloating in the CO ₂ group ( P  = 0.0012). However, we observed only a trend to lower post-interventional pain ( P  = 0.15) and a lower pain score. There was no significant difference in transcutaneous pCO ₂ level and no adverse events occurred. Although there was no difference in the dosage of propofol and midazolam, we observed a significant increased necessity for use of synthetic opioids in the RA group to achieve optimal examination conditions ( P  = 0.023). Conclusions  The benefits using CO ₂ in colonoscopy of deeply sedated children predominate. In particular, CO ₂ insufflation may allow a less painful post-interventional time and it significantly reduces abdominal bloating. Moreover, with CO ₂ , significantly less additional opioids were used. Thus, CO ₂ insufflation can be considered as safe in deeply sedated patients as there was no relevant pulmonary CO ₂ retention observed. (DRKS00013914).

Submucosal Tunnel Endoscopic Resection for Esophageal Submucosal Tumors: A Multicenter Study

Background

Submucosal tumors (SMTs) are primarily benign tumors, but some may have a malignant potential. Endoscopic submucosal dissection that has been used for removing esophageal SMTs could cause perforation. Submucosal tunnel endoscopic resection (STER) is an improved and an effective technique for treating esophageal SMTs.

Aims

This study was conducted to evaluate the efficacy and safety of STER for treating esophageal SMTs.

Methods

A retrospective study design was adopted to analyze the baseline characteristics, clinical outcomes, and follow-up data of patients with esophageal SMTs, which originated from the muscularis propria layer and were treated with STER from September 2011 to May 2018.

Results

A total of 119 lesions were included from 115 patients who were successfully treated with STER. The mean age of the patients was 49.7 ± 10.7 years. The lesions were primarily located in the middle and lower esophagus. The mean size of the lesions was 19.4 ± 10.0 mm. The mean operation duration was 46.7 ± 25.6 min, and the mean duration of hospitalization was 5.9 ± 2.8 days. The total en bloc resection rate and the complete resection rate were 97.5% and 100%, respectively. Regarding complications, there were 9 (7.8%) cases of perforation, 2 (1.7%) cases of pneumothorax, and 9 (7.8%) cases of subcutaneous emphysema. Histopathological results revealed 113 (95.0%) cases of leiomyoma, 5 (4.2%) cases of gastrointestinal stromal tumors, and 1 (0.8%) case of a granular cell tumor. During the mean 15-month follow-up, there were no cases of recurrence and distant metastasis.

Conclusions

STER is a safe and feasible technique for treating esophageal SMTs originating from the muscularis propria layer.

Endoscopic Submucosal Tunnel Dissection for Upper Gastrointestinal Submucosal Tumors Originating from the Muscularis Propria Layer: A Single-Center Study

Background/Aims

In recent years, endoscopic submucosal tunnel dissection (ESTD) has gained popularity worldwide. The aim of this study was to evaluate the safety and efficacy of ESTD in treating upper gastrointestinal submucosal tumors (SMTs) in a large-volume endoscopic center.

Methods

Patients with SMTs were enrolled in this study between January 2012 and January 2015. Demographic data, clinical data, and treatment outcome were collected and analyzed.

Results

Seventy SMTs originating from the muscularis propria (MP) layer were identified in 69 patients. All patients successfully underwent the ESTD procedure. The mean procedure time was 49.0±29.5 minutes, and the mean tumor size was 18.7±7.2 mm. Among all lesions, the majority (70.0%) were located in the esophagus, 12.9% in the cardia, and 17.1% in the stomach. Complete resection was achieved in 67 lesions (95.7%). Perforation occurred in three patients (4.3%), who were treated by endoclips. Pneumothorax occurred in two patients (2.9%) and was successfully managed by thoracic drainage. During a median follow-up of 18.1 months, patients were free of local recurrence or distant metastasis.

Conclusions

Our results demonstrated the feasibility and safety of ESTD in treating upper gastrointestinal SMTs originating from the MP layer. Large-scale comparative studies with other treatment methods should be conducted in the future.

Does carbon dioxide insufflation impact adenoma detection rate? A single-center retrospective analysis

Background and study aims: Carbon dioxide (CO₂) has been associated with reduced post-procedural pain and improved patient satisfaction when compared to air insufflation (AI). The effect of CO₂ insufflation (CO₂I) on the adenoma detection rate (ADR) remains unclear. The aims of this study are to compare ADR in patients undergoing screening colonoscopy with AI vs. CO₂I and identify predictors of ADR. Patients and methods: Single-center retrospective cohort study of 2,107 patients undergoing screening colonoscopy at the University of Florida Hospital between November 2011 and June 2015. Patient demographics, procedural parameters, and histology results were retrospectively obtained from a prospectively maintained colonoscopy database. Univariate and multivariate analysis were performed to identify predictors of ADR. Results: A total of 2107 colonoscopies (644 with AI and 1463 with CO₂I) were analyzed. Overall ADR was 27.8 %. There was no significant difference in ADR between AI (27.6 %) vs. CO₂I (27.8 %) (P = 0.93). Method of insufflation (AI vs. CO₂I) was not significantly associated with ADR (OR 0.9; 95 % CI:0.7 - 1.2). Older age (OR: 1.02; 95 % CI: 1.001 - 1.03 per year increase), male gender (OR 1.48; 95 % CI: 1.17 - 1.87), and longer scope withdraw time (OR 1.13; 95 % CI: 1.1 - 1.16 per minute) were associated with a higher ADR. Fellow involvement was negatively associated with ADR (OR 0.60; 95 % CI: 0.47 - 0.77). Conclusion: ADR was similar between patients who underwent screening colonoscopy with AI vs. CO₂I. While CO₂I has been associated with improved patient comfort and post-procedural recovery time, there is no definitive evidence to suggest that this method of luminal distention enhances ADR.

Randomized, double-blind trial of CO2 versus air insufflation in children undergoing colonoscopy

BACKGROUND AND AIMS

Studies in adults have shown that postprocedural abdominal pain is reduced with the use of carbon dioxide (CO(2)) instead of air for insufflation during colonoscopy. The aim of our study was to compare postprocedural abdominal pain and girth in children undergoing colonoscopy using CO(2) or air for insufflation.

METHODS

This was a prospective, randomized, double-blind study that included 76 consecutive pediatric patients undergoing colonoscopy for various indications. Patients were randomly assigned to either CO(2) or air insufflation. At 2, 4, and 24 hours after the examination, the patients' pain was assessed by using the 11-point numerical rating scale. The waist circumference was measured 10 minutes and 2 and 4 hours after colonoscopy.

RESULTS

A significantly higher proportion of patients had no pain after colonoscopy in the CO(2) group compared with the air group (82 vs 37% at 2 hours and 95% vs. 63% at 4 hours, P < .001). Mean abdominal pain scores 2 and 4 hours after the procedure were statistically significantly lower in the CO(2) group compared with the control air group (0.5 vs 2.6 at 2 hours and 0.1 vs 1.2 at 4 hours, P < .001). There was no difference in waist circumference between the 2 groups at all time intervals.

CONCLUSION

The results of this randomized trial show clear benefits of CO(2) insufflation for colonoscopy in reducing postprocedural discomfort. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT02407639.).

Factors predicting the technical difficulty of peroral endoscopic myotomy for achalasia

BACKGROUND

Peroral endoscopic myotomy (POEM) has been described as a novel treatment for esophageal achalasia. Owing to its technical difficulty, POEM is not widely performed. This study was aimed to prospectively assess the factor predicting technical difficulty of POEM in a single center with large volume cases.

METHODS

A total of 105 cases of achalasia treated by POEM from April 2011 to September 2014 were analyzed. Difficult cases of POEM were defined as procedure time ≥90 min and occurrence of adverse events, including mucosal perforation, pneumothorax, and major bleeding. Univariate and multivariate logistic regression analyses were performed to assess the predictive factors of difficult POEM.

RESULTS

POEM was successfully completed in all the patients, and no one was converted to laparoscopy. The number of cases with procedure time ≥90 min was 17. Mucosal perforations occurred in six (5.7 %) patients during submucosal tunnel creation, major bleeding occurred in seven (6.7 %) patients, and pneumothorax occurred in six (5.7 %) patients immediately after procedure. All the complications were managed conservatively. No other intraoperative and immediate postoperative complications, including infections and pneumoperitoneum, occurred. Multivariate analysis showed that early period (odds ratio [OR] 4.173, 95 % confidence interval [95 % CI] 1.36-6.829, P = 0.023) and triangular tip knife ([OR] 6.712, [95 % CI] 1.479-30.460, P = 0.014) were independent factors associated with technical difficulty regarding longer procedure time (procedure time ≥90 min).

CONCLUSION

POEM is safe for the treatment of esophageal achalasia. Triangular tip knife and early period were independent risk factors for longer procedural time.

Carbon dioxide insufflation during screening unsedated colonoscopy: a randomised clinical trial

One of the methods used to reduce pain and discomfort during colonoscopy is insufflation of carbon dioxide instead of air. However, the actual benefit of carbon dioxide insufflation is not unequivocally proven. The aim of the study was to evaluate the advantages of carbon dioxide insufflation during screening colonoscopy. A total of 200 patients undergoing screening colonoscopy between 2010 and 2011 were included in the prospective, randomized study carried out in a surgical referral center. Screening unsedated colonoscopy with either air or carbon dioxide insufflation was performed; patients were randomly assigned to air or carbon dioxide group by means of computer-generated randomization lists. All examinations were performed in an ambulatory setting with standard videocolonoscopes. The main outcomes analyzed were (a) duration of the entire procedure, (b) cecal intubation time, and (c) pain severity immediately, 15, and 60 min after the procedure. Group I included 59 women and 41 men and group II included 51 women and 49 men. The duration of the procedure was circa 10 min in both groups. Pain score values immediately and 15 min after the procedure were similar in both groups (P=0.624 and 0.305, respectively). A lower pain score was observed only after 60 min in patients insufflated with carbon dioxide (1.28 vs. 1.54, P=0.008). No pain reduction was observed in women and in obese patients (BMI>30). Carbon dioxide insufflation during unsedated screening colonoscopy does not decrease the duration of the procedure and appears to reduce pain intensity at 60 min after examination to an extent without clinical significance. The study was registered at ClinicalTrials.gov, number NCT01461564.

Peroral endoscopic myotomy for esophageal achalasia

Peroral endoscopic myotomy (POEM) is one of the alternative treatment for achalasia. Due to concept of natural orifice transluminal endoscopic surgery (NOTES), it becomes popular and widely accepted. With the endoluminal technique, submucosal tunnel was created followed by endoscopic myotomy. POEM is not only indicated in classical achalasia but also other abnormal esophageal motility disorders. Moreover, failures of endoscopic treatment or surgical attempted cases are not contraindicated for POEM. The second attempted POEM is also safe and technically feasible. Even though the legend of success of POEM is fruitful, the possible complications are very frightened. Good training and delicate practice will reduce rate of complications. This review provides a summary of current state-of-the-art of POEM, including indication equipments, technique and complications. This perfect procedure may become the treatment of choice of achalasia and some esophageal motility disorders in the near future.

Dynamic article: steady pressure CO2 colonoscopy; its feasibility and underlying mechanism

BACKGROUND

Steady pressure automatically controlled endoscopy is a new insufflation concept, achieving a laparoscopy-like steady environment in the upper GI tract, recently reported in the esophagus.

OBJECTIVE

The purpose of this work was to validate the feasibility and safety of steady pressure automatically controlled endoscopy in the lower GI tract and to identify major factors that enable it.

DESIGN

This was a nonsurvival animal study using canine models.

SETTINGS

The study was conducted in an academic center.

PATIENTS

Canine models were used in this study.

INTERVENTIONS

In experiment 1, steady pressure automatically controlled endoscopy was attempted in the cecum with insufflation pressures of 4, 8, and 12 mm Hg. We assessed performance by video review and continuous intracecal pressure monitoring. Next, steady pressure automatically controlled endoscopy was performed for 20 minutes under optimal pressure, 8 mm Hg (n = 10). In experiment 2, steady pressure automatically controlled endoscopy was attempted in the rectum with or without artificial colonic flexure and with either low (8 mm Hg) or high (16 mm Hg) insufflation pressure to assess the effects of anatomic flexure and insufflation pressure on the establishment of steady pressure automatically controlled endoscopy (n = 6).

MAIN OUTCOME MEASURES

We measured multipoint intraluminal pressure monitoring in the upstream bowel, as well as cardiopulmonary parameters.

RESULTS

For experiment 1, steady pressure automatically controlled endoscopy in cecum was successful at all of the tested insufflation pressures; 8 mm Hg provided the optimal result. Steady pressure automatically controlled endoscopy was safely performed for 20 minutes at 8 mm Hg without any cardiopulmonary parameter changes or intraluminal pressure elevation in the upstream bowel. For experiment 2, confinement of the steady pressure environment to the rectum was achieved only with the assistance of colonic flexure and at 8 mm Hg insufflation pressure. In other conditions, the insufflated gas extended throughout the entire colon.

LIMITATIONS

This study was limited by being an animal study.

CONCLUSIONS

Steady pressure automatically controlled endoscopy is feasible and safe in the lower GI tract under the optimized insufflation pressure and in the presence of anatomical flexure (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A150).

Precise tumor size measurement under constant pressure by novel real-time micro-electro-mechanical-system hood for proper treatment (with videos)

Background

Tumor size determination is subject to the measurement method used by endoscopists and is especially dependent on the air quantity. As the intraluminal pressure must be measured objectively to obtain an accurate tumor size measurement, insufflation can affect the results. Thus, we examined the utility of a micro-electro-mechanical-system (MEMS) pressure sensor hood.

Methods

Twenty consecutive air insufflation/deflation tests were performed in vivo using a dog’s stomach. Correlations between the actual pressure measured and the signal strength of the MEMS hood were measured. We marked 2 points 20 mm on the antrum and another 3 points, with insufflation corresponding to the maximum stable distance of two markings. We performed five insufflation/deflation tests to obtain the relationship between pressure and distances to accurately measure the distance under constant pressure.

Results

In the air insufflation/deflation test performed 20 consecutive times, the MEMS hood signal strength (V) and the pressure measurement sensor values (mmHg) showed good correlation. There was good correlation between intraluminal pressures of 2.5–40 mmHg and the two marking distances on the antrum (correlation coefficient 0.952) (P < 0.05). However, once the intraluminal pressure reached a certain level (40 mmHg), expansion of the two marking distances ceased. The same measurements were conducted on the greater curvatures of the lower body and middle body and on the lesser curvature of the lower body.

Conclusions

Correct tumor size measurements using a MEMS hood enable a more accurate diagnosis, which can be used to develop suitable treatment strategies.

Electronic supplementary material

The online version of this article (doi:10.1007/s00464-014-3642-3) contains supplementary material, which is available to authorized users.

Carbon dioxide insufflation reduces number of postprocedure admissions after endoscopic resection of large colonic lesions: a prospective cohort study

BACKGROUND

Endoscopic resection (ER) for large colonic lesions is a safe and effective outpatient treatment. Postprocedural pain creates concern for perforation and often results in postprocedure admission (PPA). Carbon dioxide (CO(2)) insufflation has been shown to reduce pain scores after routine colonoscopy, but an influence on more critical outcomes such as PPA has not been shown.

OBJECTIVE

To assess the outcomes of patients undergoing ER for large colonic lesions, comparing those having air versus those having CO(2) insufflation.

DESIGN

Prospective, observational, cohort study.

SETTING

Academic, high-volume, tertiary-care referral center.

PATIENTS

Consecutive patients referred for ER of sessile colorectal polyps ≥20 mm.

INTERVENTION

ER with air or CO(2).

MAIN OUTCOME MEASUREMENTS

Rates of PPA, technical outcomes, complication rates.

RESULTS

ER was performed on 575 lesions ≥20 mm, 228 with CO(2) insufflation. Mean lesion size was 36.5 mm. Lesion and patient characteristics were similar in both groups. The use of CO(2) was associated with a 62% decrease in the PPA rate from 8.9% to 3.4% (P = .01). This was mainly because of an 82% decrease in PPA for pain from 5.7% to 1.0% (P = .006). There were no significant difference in the rates of complications. Multiple logistical regression was performed. The adjusted odds ratio (OR) of PPA (OR 0.39; 95% confidence interval [CI], 0.16-0.95; P = .04) and PPA for pain (OR 0.18; 95% CI, 0.04-0.78; P = .02) in the CO(2) group remained significant.

LIMITATIONS

Single center, nonrandomized study.

CONCLUSION

CO(2) insufflation significantly reduces PPA after ER of large colonic lesions, primarily because of reduced PPA for pain. CO(2) insufflation should be routinely used during ER of large colonic lesions.

[Colonoscopy with carbon dioxide insufflation: luxury or neccesity?]

Colonoscopy is an essential diagnostic and therapeutic tool for many gastrointestinal diseases and is also a key element in the prevention and early diagnosis of colon cancer. Despite numerous technical advances, colonoscopy continues to be uncomfortable for patients, both during and after the procedure. To a large extent, the discomfort of colonoscopy depends on the need to distend the colon, which usually produces abdominal pain. Although ambient air is usually employed to expand and inflate the colon, in the last few years devices that allow carbon dioxide (CO(2)) insufflation in colonoscopy have been developed. This gas is a highly attractive option for pain-free colonoscopy.

Carbon dioxide-induced inhibition of mechanical activity in gastrointestinal smooth muscle preparations isolated from the guinea-pig

Mechanical responses of smooth muscle elicited by application of CO2-gas bubbled physiological salt solution (CO2-gas solution) were investigated in isolated stomach antrum and colon preparations of the guinea-pig. Circular smooth muscle preparations of both colon and stomach were spontaneously active with periodic generation of phasic contractions. In colonic preparations, the CO2-gas solution produced a biphasic response, with an initial small transient contraction followed by a sustained inhibition of phasic contractions. Removal of the CO2-gas solution allowed a slow recovery of the spontaneous contractions over a period of about 40 min. The recovery developed with a similar time course irrespective of the length of time exposed to CO2-gas solution. The inhibitory responses elicited by CO2-gas solution were not modulated by atropine, Nω-nitro-L-arginine or neostigmine. Atropine-sensitive excitatory responses of smooth muscle elicited by transmural nerve stimulation or exogenously applied acetylcholine were attenuated or abolished in the presence of CO2-gas solution. In stomach preparations, the CO2-gas solution elicited a tri-phasic response, with an initial transient relaxation followed by a transient contraction and then a sustained inhibition of the rhythmic contractions. The peak amplitude of the transient contraction was about 2.5 times larger than the spontaneous phasic contractions. The pH of the CO2-gas solution was reduced to about 6. Application of pH 6 solution again produced a tri-phasic response, as was the case for the CO2-gas solution, however the amplitude of the transient contraction was only about 0.4 times that of the spontaneous contractions. The re-appearance of the abolished phasic contraction was quicker with the pH 6 solution (about 1.8 min) than it was for the CO2-gas solution (about 6 min). The inhibitory responses elicited by the CO2-gas solution could be simulated only partly by the acidified solution, and a possible involvement of additional factors in the inhibition elicited by CO2-gas solution was considered.

Meta-analysis: the use of carbon dioxide insufflation vs. room air insufflation for gastrointestinal endoscopy

BACKGROUND

Carbon dioxide (CO(2)) insufflation has been proposed as an alternative to air insufflation to distend the lumen in gastrointestinal (GI) endoscopy.

AIM

To perform a systematic review with meta-analysis of randomised controlled trials (RCTs) in which CO(2) insufflation was compared with room air insufflation in GI endoscopy.

METHODS

Electronic and manual searches were combined to search RCTs. After methodological quality assessment and data extraction, the efficacy and safety of CO(2) insufflation were systematically assessed.

RESULTS

Twenty-one RCTs [13 on colonoscopy, four on endoscopic retrograde cholangiopancreatography (ERCP), two on double-balloon enteroscopy (DBE), one on oesophagogastroduodenoscopy, and one on flexible sigmoidoscopy] were identified. For colonoscopy, CO(2) insufflation resulted lower postprocedural pain intensity, and increased the proportion of patient without pain at 1 h (RR: 1.84, 95% CI: 1.37-2.47) and 6 h (RR: 1.28; 95% CI: 1.14-1.44) postprocedure. For ERCP, the pain-releasing effect of CO(2) insufflation was not obvious (SMD: -1.48, 95% CI: -3.56, 0.59). CO(2) insufflation revealed no consistent advantages in the RCTs of DBE, but was shown as safe as air insufflation in oesophagus/stomach endoscopic submucosal dissection in one study. pCO(2) level showed no significant variation during these procedures.

CONCLUSIONS

Compared with air insufflation, CO(2) insufflation during colonoscopy causes lower postprocedural pain and bowel distension without significant pCO(2) variation. More RCTs are needed to assess its advantages in other GI endoscopic procedures.

Abdominal ultrasound after colonoscopy with insufflation of carbon dioxide versus air

OBJECTIVE

To investigate whether the use of carbon dioxide (CO(2)) compared with air insufflation during colonoscopy improves ultrasonography after the procedure.

MATERIAL AND METHODS

In a double-blind trial, 30 patients were randomized to insufflation with CO(2) or air. Thirty minutes after colonoscopy abdominal ultrasound was performed. Immediately after ultrasonography, the ultrasound quality of the liver, gallbladder, biliary ducts, pancreas, spleen, kidneys, abdominal vessels, antrum, bowel, urinary bladder and prostate/uterus was evaluated for optimal ultrasound scanning quality, minor reduction of scanning conditions, major reduction of scanning conditions and unacceptable scanning conditions.

RESULTS

Ultrasound quality 30 min after colonoscopy was significantly better when using CO(2) insufflation instead of air (p<0.003). Significant improvement in imaging quality was observed for the liver, portal vein, splenic vein, all three divisions of the pancreas, aorta, coeliac trunk, superior mesenteric artery, iliac vessels, left kidney and uterus.

CONCLUSIONS

Ultrasound investigation can be done after a colonoscopy with CO(2) insufflation, whereas it is not recommended after a colonoscopy with air insufflation. In selected cases, this approach may enable and improve post-colonoscopy ultrasound scanning.

The use of carbon dioxide for insufflation during GI endoscopy: a systematic review

BACKGROUND

Insufflation of the lumen is required for visualization during GI endoscopy. Carbon dioxide (CO(2)) has been proposed as an alternative to room air for insufflation.

OBJECTIVES

To assess the safety and efficacy of CO(2) insufflation for endoscopy.

DESIGN

Systematic review that focuses on evidence from randomized controlled trials (RCT).

METHODS

Two investigators independently searched MEDLINE from 1950 to February 13, 2008, to identify all articles that reported the use of CO(2) in a GI endoscopy application. Bibliographies of relevant articles were also hand searched to identify other pertinent reports. Data from RCTs, as well as from nonrandomized studies, were extracted.

RESULTS

Nine RCTs were identified that compared CO(2) and air insufflation for GI endoscopy. Fifteen other nonrandomized studies or reports were also reviewed. In the 8 RCTs in which postprocedural pain was assessed, pain was lower in the CO(2) insufflation group compared with the air group. Two RCTs found decreased flatus in the CO(2) group compared with the air group, and 3 RCTs showed there was decreased bowel distention on abdominal radiography in the CO(2) group compared with the air group. Also, in all 9 RCTs and 6 additional studies in which safety was assessed, there was no CO(2) retention and no adverse pulmonary events related to CO(2) insufflation.

LIMITATIONS

Because of study heterogeneity, meta-analytic techniques could not be used.

CONCLUSIONS

Consistent RCT evidence indicates that CO(2) insufflation is associated with decreased postprocedural pain, flatus, and bowel distention. CO(2) insufflation also appears to be safe in patients without severe underlying pulmonary disease.

The role of intraoperative carbon dioxide insufflating upper gastrointestinal endoscopy during laparoscopic surgery

BACKGROUND

Intraoperative endoscopy (IOE) is a useful adjunct during laparoscopic gastrointestinal (GI) surgery. However, one potential hazard of IOE is a prolonged bowel distension due to insufflated air, which may cause obstructed surgical exposure and increased postoperative abdominal pain. Recently, carbon dioxide (CO(2)), with its rapid absorptive nature, has been proven effective to minimize prolonged bowel distension in ambulatory/intraoperative colonoscopy. The objectives were to assess the feasibility, safety, and efficacy of CO(2)-insufflating upper GI IOE during laparoscopic surgery.

METHODS

A historical comparison study was performed on the initial ten consecutive patients who underwent CO(2)-insufflating upper GI IOE (CO(2)-IOE) during laparoscopic surgery. The control group consisted of the past 12 consecutive patients who underwent conventional air-insufflating upper GI IOE (air-IOE) during laparoscopic surgery. The following parameters were compared between the two groups: (1) patient demographics; (2) feasibility (% completion of IOE); (3) safety (complications related to IOE, impacts on cardiopulmonary status, including systemic blood pressure, heart rate, and end-tidal CO(2)); (4) efficacy (postoperative residual intestinal gas, time to resume oral intake, and bowel movement). The amounts of post-IOE residual intestinal gas were evaluated and classified on the immediate postoperative abdominal radiographs in a blinded manner.

RESULTS

Patient demographics were comparable between the two groups. IOE was completed in both groups without complications. Adverse effects on cardiopulmonary status were not observed during simultaneous intraperitoneal and intraluminal CO(2) insufflation. In the air-IOE group, one patient was converted to open surgery because of inadequate surgical exposure from prolonged distension of the downstream bowel. The patients in the CO(2)-IOE group had significantly lower grade of postoperative bowel distension than the control group. Postoperative oral intake was resumed earlier in the CO(2)-IOE group.

CONCLUSION

CO(2)-insufflating upper GI IOE during laparoscopic surgery is feasible, safe, and has a practical advantage in minimizing post-IOE bowel distension compared with conventional air-insufflating upper GI IOE.