Recommended practices for the prevention of unplanned perioperative hypothermia

AORN Journal,  May, 2007  

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3. Effective methods of preventing unplanned hypothermia should be used. These methods involve skin surface warming including, but not limited to,

* Forced-air warming, which is safe and the most widely used skin surface warming method. The efficacy of forced-air warming in preventing unplanned hypothermia has been proven in many clinical trials. (11,81-86) The method is effective in neonates, (87) pediatric patients, (85) and morbidly obese patients. (88) Forced-air warming has also been found to be effective in rewarming patients after cardiopulmonary bypass. (89-91) Forced-air warming does not increase the risk of wound contamination. (83,92)

* Circulating-water garments that circulate warm water through a special, segmented, conductive-heating garment wrapped around the patient. This method has been found to effectively transfer heat to the patient and maintains normothermia in adult (93-97) and pediatric patients. (98) Circulating-water garments maintained normothermia better than a combination of water blanket and fluid warmer in patients undergoing on-pump (96) or off-pump (94,95) cardiopulmonary bypass. Studies have shown that more heat is transferred to the patient by a circulating water garment than forced-air warming. (97) Compared to an upper body forced-air blanket, normothermia was maintained better using the circulating-water garments in patients undergoing abdominal surgery. (99) Circulating-water garments have also been found to effectively rewarm patients after cardiopulmonary bypass (94,100,101) and to rewarm hypothermic patients better than a full body forced-air blanket. (97)

* Energy transfer pads that circulate water through a set of heat-exchange pads that adhere to the patient's skin. Energy transfer pads have been found to be an effective tool to reduce intraoperative hypothermia during off-pump cardiac surgery. (102)

4. Warming intravenous (IV) fluids should be considered only if large volumes (ie, more than 2 liters/hour for adults) are being administered. Warming IV fluids to near 37[degrees]C (98.6[degrees]F) prevents heat loss from the administration of cold IV fluids and should be considered as an adjunct to skin surface warming. When less than 2 liters of volume is given, fluid warming is of limited value because fluid-induced cooling is minimal. In studies of patients undergoing major surgery, the combination of forced-air warming and fluid warming decreased the risk of hypothermia more than forced-air warming alone. (103,104) In one study, however, the average temperature in patients in both groups was normothermic. (104) Fluid warming is not a substitute for forced-air warming, which usually transfers far more heat, and warmed fluids alone will not usually keep patients normothermic. (60,104,105) When fluids are being warmed, technology designed for this purpose should be used according to the manufacturers' written instructions.

5. Warming irrigation solutions to be used inside the abdomen, pelvis, or thorax should be considered. Warmed irrigation fluid (near 37[degrees]C [98.6[degrees]F]) should be used as adjunct therapy to decrease heat loss, but it is insufficient alone to prevent hypothermia. In a study of patients undergoing laparoscopy without forced-air warming, patients receiving warmed irrigation solutions maintained higher core body temperatures than those receiving room temperature solutions; (24,106) however, warmed irrigation fluids alone did not prevent hypothermia. (106) No improvement in body temperature was found when using warmed irrigation during arthroscopic surgery. (107) When using warmed irrigation solutions, the temperature of the solution should be measured with a thermometer at the point of use and verified before instillation. Irrigating with hot solutions has resulted in patient injuries.