HEMODYNAMIC-EFFECTS OF ARGON PNEUMOPERITONEUM

The hemodynamic effects of argon pneumoperitoneum were studied to defi ne its possible role as an alternative gas for intraperitoneal insuffl ation during minimally invasive surgery. Adult pigs were anesthetized and placed on mechanical ventilation. Parameters measured or determine d included mean arterial (MAP), pulmonary arterial (PAP), pulmonary ar terial wedge (PAWP), right atrial (CVP), and inferior vena cava venous (IVC) pressures, total excretion of CO2 (VCO2), oxygen consumption (V O2), minute ventilation, and arterial blood gases. Also determined wer e cardiac output, stroke volume, and systemic vascular resistance all indexed to weight (CI, SVI, SVRI). Data were recorded during a 1-h bas eline, 2 h of insufflation with argon gas at a constant pressure of 15 mmHg, and 1 h recovery after desufflation. There was no significant c hange from baseline in VCO2, VO2, MAP, PAP, PAWP, CVP, PaCO2, or arter ial pH. Argon pneumoperitoneum significantly increased systemic vascul ar resistance index and exerted a depressant effect on stroke volume i ndex and cardiac index by 25% and 30% from baseline values, respective ly (P < 0.05). Inferior vena cava pressure increased as a reflection o f the intraabdominal pressure. Argon insufflation had no effect on res piratory function. Argon gas may not be physiologically inert, and in patients with cardiovascular disease its effects may be clinically imp ortant.