Study Objective To determine whether residual gas volume reduces more quickly after insufflation with humidified CO2 compared with dry CO2. Design Animal study (Canadian Task Force classification I). Setting University. Intervention Piglets were randomly divided into two groups of five and underwent abdominal insufflation with either cold, dry CO2 or warm, humidified CO2. Measurements and Main Results Following insufflation, anteroposterior and lateral gas-bubble radiographic images were obtained at 5, 15, 30, 45, and 60 minutes, and the area of each gas-bubble profile calculated. Blood samples were obtained at 0, 2, 4, and 5 hours, and they were analyzed for IL-1β and TNFα. Peritoneal tissue samples were obtained on euthanasia at 5 hours for histological analysis. The results indicate that following pneumoperitoneum, residual CO2 dissipates more rapidly when the gas is heated and humidified compared with when it is cool and dry. This is associated with a reduction in the duration of the inflammatory response as measured by TNFα production, although no histologic differences in the peritoneal tissue were observed. Conclusion Heating and humidifying CO2 leads to faster dissipation of residual gas associated with a reduced duration of inflammation, which may contribute toward a reduction in postlaparoscopic pain.
