The peritoneal response to injury and implications for laparoscopic insufflation

Abstract

To elucidate the effect of the cold, dry pneumoperitoneum used in laparoscopic surgery on peritoneal inflammatory response, and determine its impact on clinical outcome. Methods The literature on peritoneal physiology was reviewed, focusing on the peritoneal inflammatory response and methods that should be investigated to attenuate this, including minimally invasive surgery. A meta-analysis and followup case-control study were undertaken comparing the systemic and peritoneal cytokine response in laparoscopic versus open colorectal surgery. A systematic review and follow-up double-blinded, multi-centre, randomised, controlled trial were performed evaluating the impact of warmed and humidified insufflation on postoperative pain and inflammation after laparoscopy. An experimental study was conducted in an appropriate rat model of pneumoperitoneum, investigating the impact of warming and humidification on the pneumoperitoneum associated oxidative stress response. Findings Laparoscopic surgery is associated with a local and systemic oxidative stress and inflammatory cytokine response that is similar to that seen in equivalent open surgery. This effect is over and above that of increased intra-abdominal pressure alone. Review of the literature indicates that this inflammatory response may be caused by peritoneal desiccation due to insufflation of cold, dry carbon dioxide. However, these findings are limited by the quality of the published studies reviewed. The results of the investigations conducted in this thesis indicate that warming and humidification of insufflation gases do not reduce oxidative stress marker or cytokine levels, and do not confer any clinical benefit in prolonged laparoscopy. Conclusions Dessication caused by cold, dry gas insufflation does not contribute significantly to the inflammatory response associated with pneumoperitoneum. Future research should re-assess the aetiology and occurrence of this response using more accurate and clinically relevant models of laparoscopic surgery.