Cardiopulmonary changes during laparoscopy and vessel injury: comparison of CO2 and helium in an animal model

Background: Injury of venous vessels during elevated intraperitoneal pressu re is thought to cause possible fatal gas embolism, and helium may be dange rous because of its low solubility. Methods: Twenty pigs underwent laparosc opy with either CO2 (n=10) or helium (n=10) with a pressure of 15 mmHg and standardized laceration (1 cm) of the vena cava inferior. After 30 s, the v ena cava was clamped, closed endoscopically by a running suture and unclamp ed again. During the procedure changes of cardiac output (CO), heart rate ( HR), mean arterial pressure (MAP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), end tidal C O2 pressure (PETCO2), and arterial blood gas analyses (pH, pO(2) and pCO(2) ) were investigated. Results: No animal died during the experimental course (mean blood loss during laceration: CO2, 157+/-50 ml; helium, 173+/-83 ml) . MAP and CO values showed a decrease after laceration of the vena cava in both groups that had already been completely compensated for before suturin g. PETCO2 increased significantly after CO2 insufflation (P<0.01), while he lium showed no effect. Laceration of the vena cava caused no significant ch anges in PETCO2 values in either group. Significant acidosis and an increas e of pCO(2) were only found in the CO2 group. Conclusions: The incidence of gas embolism during laparoscopy and accidental vessel injury seems to be v ery low. With the exception of acidosis and an increase of PETCO2 in the CO 2 group, there were no differences in cardiopulmonary function between insu fflation of CO2 and helium.