Incidence of Inadvertent Intraoperative Hypothermia with Continuous Air Forced Active Warming. Single Center, Retrospective Study

Intraoperative hypothermia has been clearly shown in numerous studies to influence various postoperative outcomes. Therefore, body temperature maintenance is performed throughout operations. However, the incidence of hypothermia during surgery with active warming is as yet unknown. We determined the incidence of hypothermia during surgery with active warming at our hospital. Methods: We reviewed 25,518 anesthesia records in our hospital. There were 5,620 casesin which intraoperative body temperature had not been measured and thus lacked reliable body temperature data. These cases were manually excluded. After exclusion of these cases, we divided the remaining patients into two groups; hypothermia with body temperatures less than 36°C and normothermia with body temperatures of 36°C to 38°C. Results: Hypothermia occurred in 9,970 of 18,274 cases. There were 8,276 normothermic cases. As to the type of surgery, head and neck operations, including neurosurgeries, and also pediatric surgery, were associated with a low incidence of hypothermia. Discussion: Although all of these cases received active warming employing an air forced warmer, the hypothermia incidence was still 54.5%. Abdominal and thoracic surgeries were associated with higher incidences of hypothermia than other procedure categories, while the incidence was lower with head and neck surgery. This is attributable to the body being mostly covered during head and neck surgery. The low incidence of hypothermia during pediatric surgery was attributed to higher room temperature and more continuous active warming than during other surgical procedures. In this study, although there were some problems with analysis of the data, due to variability in measuring sites and lack of accurately measured data in several cases, the data presented herein highlight the importance of payingstrict attention to maintaining body temperature intraoperatively and to continue warming patients.