Nitrous oxide in isufflation does not increase the incidence of gas embolism during laparoscopic cholecystectomy: detection by transoesaphageal echocardiograply

ABSTRACT

In a prospective randomized clinical trial, 24 patients with ASA score I or II were scheduled for laparoscopic cholecystectomy. They were divided into two equal groups, where either carbon dioxide [CO2] or nitrous oxide [N2O] was used for pneumoperitoneum. Standard general anesthesia was used in all cases. Transesophageal echocardiography [TEE] probe was introduced to monitor gas embolism [GE] events. The procedure was divided into four operative stages [T1 = insufflation, T2 = dissection of cystic duct and artery, T3 = gallbladder bed dissection and T4 = extraction and desufflation]. For each stage, the number and score [from 1-3] of gas embolism episodes were recorded. In addition, heart rate [HR], mean arterial blood pressure [MAP], saturation of oxygen [SaO2] and end-tidal CO2 [ET CO2] were recorded immediately after induction [baseline], during insufflation and every ten minutes of the procedure. The study concluded that during laparoscopic cholecystectomy, insufflating gas does not increase the incidence of GE events compared with CO2. On the contrary, N2O exhibits slightly less GE events in some of the operative stages. The stage of insufflation predisposes to more GE events than the rest of the operation. Most of the GE events are associated with some rate of gas flow into the peritoneal cavity, whatever the type of gas is. Therefore, more cautions must be taken into consideration whenever there is active gas flow into the peritoneal cavity for the risk of GE