[Efficacy of ring-shape cover in active skin surface warming in neonates--a retrospective comparative study with...

Prevention of perioperative hypothermia is one of the most essential factor for neonatal anesthesia. Recently the forced-air warming system has been considered the most effective method in preventing perioperative hypothermia in adults, in children, and in infants during maxillofacial operations. However, its use for abdominal or thoracic surgery in neonates has not been examined. In the present study, we studied the effects of the forced-air warmer with a ring-shape cover, and compared this method with the conventional method retrospectively.

Sixteen neonates, 13 for abdominal and 3 for thoracic surgery were anesthetized with oxygen-air (nitrous oxide) sevoflurane (isoflurane or enflurane) in combination with/without fentanyl. They were divided into two groups; one for forced-air warming (F-group), and another for conventional methods (C-group). The patients' mean age, height and weight, the duration of anesthesia, infusion rate (ml.kg-1.hr-1), and urine output did not differ each other. Patients in F-group were placed in the center of the ring-shape cover and received heated air from their surroundings. We did not use any other warming equipment or means except for an artificial nose and a warming mattress. "Medium" heated air (38 degrees C) or unheated, room temperature air were used when necessary. The operating room temperature was kept around 25 degrees C. Patients in the C-group were placed on a warming mattress and under an infrared radiant heater with the room temperature of 30 degrees C. Their extremities were covered with aluminum-foil. Rectal, deep forehead, and deep sole temperatures were monitored throughout anesthesia.

In F-group, temperatures were well maintained, while C-group failed to maintain. In F-group, the mean value of base excess at the beginning of the operation was -1.8 mM, but it was restored to normal level without administration of sodium bicarbonate. No complications were found. Thus, compared to conventional methods, the forced-air warming system with a ring-shaped cover is an efficient method for body temperature management in neonatal anesthesia.