Intraperitoneal versus Extraperitoneal Insufflation of Carbon Dioxide as for Laparoscopy

Abstract

In order to compare the effects of intraperitoneal and extraperitoneal insufflation of CO², we obtained blood gas measurements and chest radiographs in dogs during insufflation into three sites: the peritoneal cavity alone, the retroperitoneal space with communication into the peritoneal cavity, and the retroperitoneal space alone. The blood pH fell a mean of 0.11 ± 0.03 and the PaCO² rose a mean of 16.0 ± 3.7 mm Hg when insufflation included the peritoneal cavity, whereas when insufflation was limited to the retroperitoneum, the pH fell a mean of 0.05 ± 0.03 and the PaCO² rose a mean of 7.5 ± 2.8 mm Hg. Extrapleural thoracic dissection of gas was noted in one animal after insufflation limited to the retroperitoneal space. These findings confirm that there is significant absorption of CO² from the peritoneal cavity during laparoscopy with CO² insufflation, whether the pneumoperitoneum is primary or occurs secondary to retroperitoneal insufflation. If the insufflated gas is limited to the retroperitoneal space, however, the absorption of CO² appears to be reduced in this animal model. The risk of thoracic dissection of gas may be greater during extraperitoneal insufflation than during intraperitoneal insufflation.