High intra-abdominal pressure during experimental laparoscopic liver resection reduces bleeding but increases the risk of gas embolism

Background: Various recommendations exist regarding intra-abdominal pressure (IAP) during laparoscopic liver resection. A high IAP may reduce bleeding but at the same time increase the risk of gas embolism. This study investigated the effects of two different IAPs during laparoscopic left liver lobe resection in piglets. Methods: Sixteen piglets underwent laparoscopic left liver lobe resection using carbon dioxide pneumoperitoneum of either 8 or 16 mmHg (8 per group). A combination of CUSA System 200 (TM) and LigaSure (TM) instruments was used for parenchymal division. During resection, a standard injury to the left liver vein was also created to increase the risk of bleeding and/or gas embolism during the operation. Heart rate, cardiac output, and arterial, pulmonary arterial, pulmonary capillary wedge and central venous pressures were measured. Arterial blood gases were monitored continuously. Transoesophageal echocardiography was video recorded to detect and quantify gas embolism within the right cardiac ventricle. The duration of operation and bleeding were noted. Results: High IAP resulted in reduced bleeding (P = 0.016), but gas embolism occurred more frequently (P = 0.001) than with low IAP. Gas embolism disturbed gas exchange, with an increase in arterial pressure of carbon dioxide, and a decrease in arterial partial pressure of oxygen and pH. These effects were sustained for at least 30 min after surgery. Conclusion: High IAP reduces the amount of bleeding but increases the risk of gas embolism. Monitoring for gas embolism is therefore indicated if a high IAP is used during laparoscopic liver resection.