Carbon dioxide insufflation vs. conventional saline irrigation for peroral video cholangioscopy

We read with interest the article by Doi et al. [1]. The authors compared the time required to obtain a clear endoscopic image and the quality of the image between using CO₂ insufflation and saline irrigation during peroral cholangioscopy (POCS). They found that the preparation time for CO₂ insufflation was significantly shorter than that for saline irrigation while the image quality obtained by both methods was similar. This result is very helpful in clinical practice for endoscopists performing POCS.

First, CO₂ insufflation is faster and therefore safer because a long procedure time can increase the CO₂ volume, which might further increase complications, such as the depressed blood pressure observed by the authors. Although the depressed blood pressure was temporary, physicians should be aware of potential unexpected serious complications because CO₂ use during POCS has not been widely reported [2] [3]. Albert et al. [3] considered CO₂ insufflation to be advantageous in treating patients when argon plasma coagulation is applied because CO₂ is an inert, non-combustible gas that is rapidly absorbed and is highly soluble in water/blood. However, we think that the speed of CO₂ insufflation must be well controlled in order to prevent a dangerous increase in intraductal pressure, which may lead to CO₂ air embolism. This complication was not reported during POCS but has been reported in association with CO₂ insufflation in a case of right coronary artery ischemia during off-pump obtuse marginalis artery grafting [4].

Second, endoscopists may consider using CO₂ insufflation as the first choice and only consider switching to saline irrigation in particular cases, such as hemorrhagic biliary tract cancer or protruding papillary lesions, during which better images can be obtained by saline irrigation.

• References

• 1 Doi S, Yasuda I, Makashima M et al. Carbon dioxide insufflation vs. conventional saline irrigation for peroral video cholangioscopy.. Endoscopy 2011; 43: 1070-1075
• 2 Ueki T, Mizuno M, Ota S et al. Carbon dioxide insufflation is useful for obtaining clear images of the bile duct during peroral cholangioscopy (with video). Gastrointest Endosc 2010; 71: 1046-1051
• 3 Albert JG, Friedrich-Rust M, Elhendawy M et al. Peroral cholangioscopy for diagnosis and therapy of biliary tract disease using an ultra-slim gastroscope. Endoscopy 2011; 43: 1004-1009
• 4 Shim JK, Choi YS, Yoo KJ et al. Carbon dioxide embolism induced right coronary artery ischaemia during off-pump obtuse marginalis artery grafting. Eur J Cardiothorac Surg 2009; 36: 598-599