FACTORS INVOLVED IN GAS EMBOLISM AFTER LAPAROSCOPIC INJURY TO INFERIOR VENA-CAVA

This study evaluated the incidence and factors involved in the occurre nce of gas embolism after laparoscopic injuries. A 5-MHz transesophage al echocardiographic (TEE) probe was placed in 11 anesthetized pigs an d used to examine the right cardiac chambers and pulmonary artery. A c alibrated carbon dioxide analyzer continuously measured end-tidal carb on dioxide (ETCO2), The ventilatory settings were adjusted to achieve a baseline ETCO2 between 25 and 28 mm Hg, A blinded dose-response curv e for TEE and ETCO2 measurements were created by injecting 0.0007 to 1 .5 mL/kg of CO2 gas intravenously. Venotomies (N = 22) were created la paroscopically in the inferior vena cava (IVC) of the study animals. A ll TEE images were videotaped and correlated with laparoscopic events, Embolic episodes were classified by comparison with images recorded d uring the bolus studies. A variety of methods for obtaining hemostasis and repairing the venotomies were evaluated and their effects on gas embolism were studied. No emboli were noted when the venotomies were b leeding freely, the hole was directly occluded, or the proximal IVC wa s compressed. Marked embolism was seen with distal IVC occlusion or wh en there had been significant blood loss. In this situation, manipulat ion of the hole and higher intraperitoneal pressures led to higher deg rees of embolization. No emboli were seen in an open control group exc ept after significant bleeding. The TEE is the most sensitive method o f detecting gas emboli; however, the majority of episodes are not clin ically significant. Embolism of CO2 occurs when central venous pressur e is decreased by blood loss or distal compression. When significant v enous bleeding occurs, intravascular volume should be maintained and t he bleeding site should be directly occluded.