CO(2) pneumoperitoneum: what we know and what we need to know.

The development of the laparoscopic technique in surgery was so overwhelming that scientific evaluation could not keep in step. While investigators were still discussing the effects of the pneumoperitoneum on the healthy organism, laparoscopy was already performed in patients with an acute abdomen due to trauma or disease. Therefore, there is an urgent need of further experimental and clinical studies with relevant endpoints to gain external evidence concerning the benefits of diagnostic or therapeutic laparoscopy for critically ill patients. In experiments with pigs we have shown that even in a healthy organism perfusion and energy metabolism of the small bowel is impaired by a pneumoperitoneum with carbon dioxide. Under the conditions of a systemic inflammatory response syndrome induced by infusion of endotoxin, the negative effects of the pneumoperitoneum were significantly amplified. Furthermore, we found that the increased intracranial pressure as caused by a head injury was further enhanced during a pneumoperitoneum but not by the alternative method of mechanical wall retraction. The current literature dealing with the effects of a pneumoperitoneum in critically ill patients is still controversial. Our data support the results of those authors who hold the opinion that creating a pneumoperitoneum in patients with acute abdominal problems means an additional serious burden that in single cases may lead to a disaster. As evidence is lacking, the current extension of laparoscopy into the field of intensive care medicine is still a human experiment that must be performed with high responsibility, extensive monitoring, and according to the rules of a clinical study.