Changes in core temperature during peritoneal insufflation: comparison of two CO2 humidification devices in pigs.

BACKGROUND

Various modifications of the physical status of CO2 have been used to reduce hypothermia caused by flow of insufflating gas. This animal study aimed to investigate the effects on core temperature, of insufflation with CO2 using two different humidification devices: unheated, humidified CO2 using the Modified-Aeroneb system (Nektar, San Carlos, CA) and warmed, humidified CO2 using the HME-Booster (Medisize, Hillegom, The Netherlands).

METHODS

We undertook a prospective four-session study on a homogeneous group of four pigs. After general anesthesia, all animals were treated successively with the following protocols in a randomized order at 8-d intervals: Control (no pneumoperitoneum), Standard (unheated, unhumidified CO2), Modified-Aeroneb (unheated, humidified CO2 by cold nebulization), HME-Booster (heated, humidified CO2). The core temperature of the animals was recorded every 10 min.

RESULTS

The temperature decrease is significantly influenced by time (P=0.0001; ANOVA), by the insufflation method (P=0.01), and by the interaction between time and the insufflation method (P=0.0001). The method of contrasts showed the following results:--The temperature decrease in the Standard group and HME-Booster group became greater than in the Control group after 40 min (P=0.02)--The temperature decrease in the Modified-Aeroneb group became greater than in the Control group after 100 min (P=0.04)--The temperature decrease in the Modified-Aeroneb group was less than in the HME-Booster group after 40 min (P=0.04) and less than in the Standard group after 60 min (P=0.01)--The temperature decrease in the Standard group was greater than in the HME-Booster group after 160 min (P=0.005).

CONCLUSIONS

Compared with the HME-Booster system, the Modified-Aeroneb is at least as effective in limiting the drop in core temperature during laparoscopic insufflation.