Topical humidified carbon dioxide to keep the open surgical wound warm - The greenhouse effect revisited

Background: Perioperative hypothermia is common in open surgery and is associated with increased rates of wound infection. This is a result of decreased wound tissue oxygenation, which can be normalized by local warming. Recently, a technique has been developed to establish a carbon dioxide atmosphere in an open surgical wound. Therefore, the authors studied the possible "greenhouse effect" of carbon dioxide insufflation and operation lamps on wound temperature. Methods: In a fully ventilated operating room surface temperature was measured at steady state in a model of an open surgical wound containing blood agar. The wound model was randomized to either no insufflation or insufflation of dry and humidified carbon dioxide or air, respectively, at a flow of 5 l/min via a gas diffuser. The surface temperature was measured with operation lamps switched on and off, respectively. Evaporation rates were also measured. Results: With the operation fight off, the surface temperature in the control was 31.8degreesC, and with the operation light on, the temperature increased by 1.5degreesC (P < 0.001). Additional insufflation of dry carbon dioxide increased the surface temperature another 1.9degreesC (P < 0.001). hen the carbon dioxide was humidified, the evaporation rate was lowest and the surface temperature increased further to 35.6degreesC (P = 0.002). In contrast, insufflation of dry and humidified air did not have a significant effect on the evaporation rate and only marginally increased the wound temperature in comparison with the control. Conclusions: Insufflation of humidified carbon dioxide in combination with light from the operation lamps may help to keep the open wound warm during surgery.