Contributing Factors to Core Hypothermia during Spinal Anesthesia. Frank et al. (page 1330)

Abstract

Although body temperature is not commonly monitored during regional anesthesia, a study by Frank et al. suggests there may be situations in which monitoring is warranted. In 44 patients scheduled for radical retropubic prostatectomy, the team monitored core temperature of all patients before spinal anesthesia, at 15 min after spinal, at two intervals after removal of the prostate, and then at set intervals in the post anesthesia care unit. They also assessed the following clinical variables as possible predictors of core temperature reductions: duration of surgery, ambient operating room temperature, body mass, body mass index, percent body fat, age, and spinal block height.The mean core temperature of patients when admitted to the post anesthesia care unit was 35.1 ± 0.6°C. A high spinal block and increasing age were the best predictors of hypothermia. The duration of surgery, ambient operating room temperature, body mass, and body fat were not predictors of hypothermia, but the study was not large enough to conclusively rule out these factors. Vasomotor tone and shivering are inhibited below the level of spinal block, so the greater the proportion of the body that is blocked, the greater the level of thermoregulatory dysfunction that can be expected. Controlling and monitoring body temperature in older patients and in those with high spinal blocks could decrease risk of hypothermia and its complications.