Venous gas embolism associated with argon-enhanced coagulation of the liver

Argon-enhanced coagulation (AEC) is a method for operative coagulation of tissues that utilizes a jet of argon gas encompassing an electrofulguration arc. Concern has been raised that the argon jet may produce harmful venous gas embolization. Two questions were addressed by this study. First, does AEC result in generation of venous gas emboli, and if so, what is the influence of gas flow rate and coagulation power on the amount of gas emboli generated? Second, does the amount of venous gas emboli generated by AEC produce harmful hemodynamic effects? Two AEC units were evaluated during coagulation of cut sections of the liver in pigs. The number of gas emboli generated was measured by an ultrasonic Doppler flow cuff placed around the caudal vena cava. Hemodynamic variables measured following AEC included systemic and pulmonary arterial pressure, pulmonary wedge pressure, and cardiac output by thermodilution. Venous gas emboli were produced during AEC of the liver. The number of gas emboli generated increased with increasing gas flow rates, but was not affected by coagulation power. No change in any of the measured hemodynamic variables was observed following AEC of the liver. The following recommendations were made: (1) Surgeons using AEC should select an argon flow rate as low as feasible to clear a bleeding tissue surface of blood and debris. (2) Although AEC seems to be associated with tolerable amounts of venous gas embolism, surgeons and anesthesiologists should be aware that the potential for harmful venous gas embolism exists. (3) In patients where extensive use of AEC is planned, appropriate monitoring and precautions for gas embolism should be undertaken.