Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

Abstract

Laparoscopic surgery is now widely performed to treat various abdominal diseases. Traditionally, the first step during laparoscopic surgery is to distend the abdomen, including entry into the abdomen and then insufflation with a gas (pneumoperitoneum), providing sufficient operating space to ensure adequate visualization of the structures and manipulation of instruments. Currently, carbon dioxide is the most frequently used gas for insufflation into the abdomen during laparoscopic abdominal surgery. However, carbon dioxide is associated with various changes in physiological parameters that affect the function of the heart or lungs (cardiopulmonary changes). Patients with poor heart or lung function may not tolerate these changes. Furthermore, carbon dioxide, which still stays in the abdomen after laparoscopic surgery, may cause postoperative pain. Thus, other gases, such as nitrous oxide and helium, have been suggested as alternatives to carbon dioxide for establishing pneumoperitoneum. This systematic review included seven trials with a total of 340 participants (the majority with low anaesthetic risk) comparing carbon dioxide pneumoperitoneum with nitrous oxide pneumoperitoneum (three trials, 196 participants) and carbon dioxide pneumoperitoneum with helium pneumoperitoneum (four trials, 144 participants). There were no trials comparing carbon dioxide pneumoperitoneum to any other gas pneumoperitoneum. All trials had a high risk of bias (suggesting the possibility of overestimating the benefits or underestimating the harms). There were no serious adverse events related to the use of either carbon dioxide or nitrous oxide pneumoperitoneum. Three serious adverse events (gas in the subcutaneous tissue) related to helium pneumoperitoneum were reported. Two of these trials showed that the pain scores were lower with nitrous oxide pneumoperitoneum than carbon dioxide pneumoperitoneum at various time points on the first post-operative day. There were no differences in the cardiopulmonary (heart and lung) complications, surgical complications, or cardiopulmonary changes between nitrous oxide and carbon dioxide pneumoperitoneum. The cardiopulmonary changes were fewer with helium pneumoperitoneum than carbon dioxide pneumoperitoneum. There were no differences in cardiopulmonary complications, surgical complications, or pain scores between helium and carbon dioxide pneumoperitoneum. In conclusion, nitrous oxide pneumoperitoneum during laparoscopic abdominal surgery appears to decrease post-operative pain in patients with low anaesthetic risk. Helium pneumoperitoneum decreases cardiopulmonary changes associated with laparoscopic abdominal surgery. However, this did not translate into any clinical benefit over carbon dioxide pneumoperitoneum. The safety of nitrous oxide and helium pneumoperitoneum has yet to be established.