Heat loss during carbon dioxide insufflation: Comparison of a nebulization based humidification device with a humidification and heating system

Introduction: This study compared the heat loss observed with the use of MR860 AEA Humidifier^TM system (Fisher & Paykel Healthcare, New Zealand), which humidifies and heats the insufflated CO₂, and the use of the AeronebProTM device (Aerogen, Ireland), which humidifies but does not heat the insufflated CO₂. Methods: With institutional approval, 16 experiments were conducted in 4 pigs. Each animal, acting as its own control, was studied at 8-day intervals in randomized sequence with the following four conditions: (1) control (C) no pneumoperitoneum; (2) standard (S) insufflation with nonhumidified, nonheated CO₂; (3) Aeroneb^TM (A): insufflation with humidified, nonheated CO₂; and (4) MR860 AEA humidifier^TM (MR): insufflation with humidified and heated CO ₂. Results: The measured heat loss after 720L CO₂ insufflation during the 4 h was 1.03 ± 0.75 °C (mean ± SEM) in group C; 3.63 ± 0.31 °C in group S; 3.03 ± 0.39 °C in group A; and 1.98 ± 0.09 °C in group MR. The ANOVA showed a significant difference with time (p = 0.0001) and with the insufflation technique (p = 0.024). Heat loss in group C was less than in group S after 60 min (p = 0.03), less than in group A after 70 min (p = 0.03), and less than in group MR after 150 min (p = 0.03). The heat loss in group MR was less than in group S after 50 min (p = 0.04) and less than in group A after 70 min (p = 0.02). After 160 min, the heat loss in group S was greater than in group A (p = 0.03). Discussion As far as heat loss is concerned, for laparoscopic procedures of less than 60 min, there is no benefit of using any humidification with or without heating. However, for procedures greater than 60 min, use of heating along with humidification, is superior.