Transcutaneous monitoring of partial pressure of carbon dioxide during endoscopic retrograde cholangiopancreatography using a double‐balloon endoscope with carbon dioxide insufflation under conscious sedation

Background and Aim A double‐balloon ( DB ) endoscope can be selectively inserted into the afferent loop to carry out endoscopic retrograde cholangiopancreatography ( ERCP ) in patients with surgically altered anatomy, allowing various types of endoscopic treatments for pancreaticobiliary diseases to be successfully carried out. In order to make such a lengthy procedure more comfortable and safe, sedatives and carbon dioxide ( CO 2 ) insufflation are widely used for gastrointestinal endoscopy. However, these techniques can increase the risk of CO 2 retention. Recently, a new sensor for transcutaneous measurement of partial pressure of carbon dioxide ( PCO 2 ) has been introduced. The aim of the present study was to evaluate the changes in transcutaneous PCO 2 ( PtcCO 2 ) during DB‐ERCP with CO 2 insufflation under conscious sedation and assess any complications related to sedation and CO 2 insufflation. Methods A total of 312 patients underwent DB‐ERCP with CO 2 insufflation at our hospital between M arch 2009 and D ecember 2012. The patients were moderately sedated using midazolamwith or without pentazocine. PtcCO 2 was measured by a non‐invasive sensor throughout DB‐ERCP in all patients. Results The mean peak PtcCO 2 during the procedure was significantly higher than the mean PtcCO 2 value before and after DB‐ERCP . Body mass index, procedure time and dose of pentazocine were significantly higher in the CO 2 retention group (peak PtcCO 2  ≥ 50 mm H g). CO 2 narcosis was observed in one case. Conclusions DB‐ERCP with CO 2 insufflation under conscious sedation might have the potential to increase the risk of CO 2 retention. Hence, non‐invasive and continuous PtcCO 2 measurement is useful for early detection of hypercapnia.