The effects of experimental venous carbon dioxide embolization on hemodynamic and respiratory variables

Laparoscopic liver resection is a relatively new surgical procedure. Carbon dioxide (CO2) pneumoperitoneum and laparoscopic liver dissection are recognized as risk factors for CO2 embolism to the pulmonary circulation. The embolization can be difficult to detect and can theoretically increase peri-operative morbidity. The aim of this study was to evaluate the cardiopulmonary effects in a pig model during a time period of 4 h after an experimental CO2 embolization. Eleven piglets were anesthesized. Nine were embolized with a single intravenous injection of 0.4 ml/kg CO2 and two served as controls. Respiratory and cardiovascular variables, including pulmonary artery pressure and cardiac output, were monitored for 4 h after embolization, and arterial blood gases were monitored on-line. The embolized piglets had an increase in ventilatory dead space, pulmonary vascular resistance and pulmonary artery pressure and a decrease in cardiac output that lasted throughout the 4-h observation time. The mean arterial pressure and heart rate were unchanged. An early sign of embolization was a rapid fall in end-tidal CO2 and P(a)o(2) and a rise in P(a)co(2). Negative changes in cardiopulmonary physiology persisted for at least 4 h after a single intravenous CO2 injection, in spite of this gas being highly soluble in blood. This is a more prolonged influence of CO2 embolization than previously described. Extensive monitoring for early detection of an embolization may be recommended to limit morbidity in patients undergoing laparoscopic liver surgery.