Safety of carbon dioxide insufflation for upper gastrointestinal tract endoscopic treatment of patients under deep sedation.

Background: It is well known that carbon dioxide (CO(2)) is absorbed faster in the body than air and also that it is rapidly excreted through respiration. This study aimed to investigate the safety of CO(2) insufflation used for esophageal and gastric endoscopic submucosal dissection (ESD) in patients under deep sedation.

Methods: Patients with either early gastric or esophageal cancers that could be resected by ESD were enrolled in this study from March 2007 to July 2008 and randomly assigned to undergo ESD procedures with CO(2) insufflation (CO(2) group) or air insufflation (air group). A TOSCA measurement system and TOSCA 500 monitor were used to measure and monitor both transcutaneous partial pressure of CO(2) (PtcCO(2)) and oxygen saturation (SpO(2)).

Results: The study enrolled 89 patients and randomly assigned them to a CO(2) group (45 patients) or an air group (44 patients). The mean CO(2) group versus air group measurements were as follows: PtcCO(2) (49.1 +/- 5.0 vs. 50.1 +/- 5.3 mmHg; nonsignificant difference [NS]), maximum PtcCO(2) (55.1 +/- 6.5 vs. 56.8 +/- 7.0 mmHg; NS), PtcCO(2) elevation (9.1 +/- 5.4 vs. 11.4 +/- 5.6 mmHg; p = 0.054), SpO(2) (99.0 +/- 0.7% vs. 99.0 +/- 1.0%; NS), minimum SpO(2) (96.5 +/- 2.4% vs. 95.4 +/- 3.3%; p = 0.085), and SpO(2) depression (2.4 +/- 2.3% vs. 3.3 +/- 2.9%; NS). The PtcCO(2) and SpO(2) measurements were similar in the two groups, but the CO(2) group was better than the air group in PtcCO(2) elevation and minimum SpO(2).

Conclusions: The findings demonstrated CO(2) insufflation to be as safe as air insufflation for upper gastrointestinal tract ESDs performed for patients under deep sedation without evidencing any adverse effects.