CO2 insufflation versus air insufflation for endoscopic submucosal dissection: A meta-analysis of randomized controlled trials

Abstract

Background: Carbon dioxide (CO2) insufflation is increasingly used for endoscopic submucosal dissection (ESD) owing to the faster absorption of CO2 as compared to that of air. Studies comparing CO2 insufflation and air insufflation have reported conflicting results.

Objectives: This meta-analysis is aimed to assess the efficacy and safety of use of CO2 insufflation for ESD.

Methods: Clinical trials of CO2 insufflation versus air insufflation for ESD were searched in PubMed, Embase, the Cochrane Library and Chinese Biomedical Literature Database. We performed a meta-analysis of all randomized controlled trials (RCTs).

Results: Eleven studies which compared the use of CO2 insufflation and air insufflation, with a combined study population of 1026 patients, were included in the meta-analysis (n = 506 for CO2 insufflation; n = 522 for air insufflation). Abdominal pain and VAS scores at 6h and 24h post-procedure in the CO2 insufflation group were significantly lower than those in the air insufflation group, but not at 1h and 3h after ESD. The percentage of patients who experienced pain 1h and 24h post-procedure was obviously decreased. Use of CO2 insufflation was associated with lower VAS scores for abdominal distention at 1h after ESD, but not at 24h after ESD. However, no significant differences were observed with respect to postoperative transcutaneous partial pressure carbon dioxide (PtcCO2), arterial blood carbon dioxide partial pressure (PaCO2), oxygen saturation (SpO2%), abdominal circumference, hospital stay, white blood cell (WBC) counts, C-Reactive protein (CRP) level, dosage of sedatives used, incidence of dysphagia and other complications.

Conclusion: Use of CO2 insufflation for ESD was safe and effective with regard to abdominal discomfort, procedure time, and the residual gas volume. However, there appeared no significant differences with respect to other parameters namely, PtcCO2, PaCO2, SpO2%, abdominal circumference, hospital stay, sedation dosage, complications, WBC, CRP, and dysphagia.

Fig 1. Flow diagram of studies identified, included, and excluded.

Fig 2. Results of quality assessment by Cochrane risk of bias.

a. each risk of bias item presented as percentages across all included studies. b. each risk of bias item for each included study.

Fig 3. Forest plot of primary outcomes of ESD with CO₂ insufflation and air insufflation.

A: post-procedural abdominal pain VAS score; SMD with 95% CI; B: Percentage of patients without pain; RR with 95% CI; C: mean PtcCO₂ levels; SMD with 95% CI; D: post-procedural PaCO₂; SMD with 95% CI.

Fig 4. Forest plot of secondary outcomes with CO2 insufflation group and air insufflation for ESD.

A: post-procedural abdominal distention VAS score; SMD with 95%CI; B: Change in abdominal circumference; SMD with 95%CI; C: post-procedural SpO2% levels; SMD with 95%CI; D: Procedure time; SMD with 95%CI; E: hospital stay; SMD with 95%CI; F: the incidence of Perforation; RR with 95%CI; G: the incidence of Haemorrhage; RR with 95%CI; H: the incidence of Pneumonia; RR with 95%CI; I: the incidence of Emphysema; RR with 95%CI; J: the mean count of white ball cell(WBC) on the day after ESD; SMD with 95%CI; K: the mean serum C-reactive protein (CRP) level on Day 3 after ESD; SMD with 95%CI; L: the midazolam dosage; SMD with 95%CI; M: the propofol dosage; SMD with 95%CI; N: the morphia dosage: SMD with 95%CI; O: redidual gas; MD with 95%CI; P: the incidence of dysphagia; OR with 95%CI.