Venous gas embolism - A comparison of carbon dioxide and helium in pigs

Abstract

Purpose: The use of helium for insufflation during laparoscopic surgery avoids hypercarbia and acidosis associated with absorbed CO2, but the effects of helium gas embolism are unknown. We compared the effects of CO2 with He gas embolism on survival, haemodynamic variables, oxygenation, and ventilation in pigs. Methods: Anaesthetized juvenile pigs were given progressively larger boluses of either CO2 (n = 5) or He (n = 4) into the right atrium. Measurements of haemodynamic variables, oxygenation, and P(ET)CO2 were made before and after each gas injection. Results: All animals survived injections of 300 ml CO2 while no animal survived more than 120 ml He (P < 0.01). Mean arterial pressure decreased more after 60 ml He (99 ± 14 to 44 ± 20 mmHg) than after 60 ml CO2 (110 ± 12 to 88 ± 14 mmHg, P < 0.001). Cardiac output did not change at any injection volume. The P(ET)CO2 decreased more after 60 ml He (30 ± 2 to 3 ± 6 mmHg) than after 60 ml CO2 (35 ± 3 to 30 ± 3 mmHg, P < 0.001). Only the He group showed a decrease in PaO2 (190 ± 51 to 68 ± 22 mmHg at 60 ml, P < 0.05). Conclusion: Helium gas embolism has a greater deleterious effect than CO2 gas embolism on survival, MAP, P(ET)CO2 and PaO2. These different effects on gas embolism should be recognized when considering the use of helium or other insoluble gases for abdominal laparoscopic insufflation.