Pneumoperitoneum and peritoneal surface changes - A review

Background: Recent evidence suggests that the use of carbon dioxide to create a pneumoperitoneum during laparoscopy can lead to adverse structural, metabolic, and immune derangements within the peritoneal cavity, and that these can be dependent on the specific insufflation gas used. These changes include structural alterations in the mesothelial lining, pH disturbances, and alterations in peritoneal macrophage responsiveness. This contrasts with an apparent systemic benefit associated with laparoscopic, as compared with open, surgery. Methods: Recently published clinical and experimental studies related to the effect of pneumoperitoneum on the peritoneal surface are reviewed, and their relevance is discussed. Results: Structural changes in the peritoneal mesothelial surface layer such as widening of the intercellular junctions can be demonstrated with electron microscopy. Acidification of the peritoneum in response to carbon dioxide insufflation occurs not only at the peritoneal surface, but also in the underlying connective tissue, resulting in disturbances in the electrical surface charge and the release of various immune mediators such as endotoxin. Pneumoperitoneum also affects the local peritoneal immune environment resulting in alterations in cytokine production and phagocytic function, as well as diminished antitumor cell cytotoxicity. Conclusions: Ultrastructural, metabolic, and immune alterations are observed at the peritoneal surface in response to a pneumoperitoneum. Experimental evidence suggests that these changes are carbon dioxide-specific effects. The consequences of these alterations to the local peritoneal environment are not well understood, but they may facilitate tumor implantation within the peritoneal cavity and adversely affect the ability to clear intraperitoneal infections. Further investigation into this area is warranted.