Body heat transfer during hip surgery using active core warming.

The purpose of this study was to evaluate the effect of core warming on heat redistribution from the core to the periphery as manifested by changes in core, mean skin temperature and mean body heat, investigated in a group of 30 patients undergoing total hip replacement. The control group (n = 10) had no active warming. Core warming was achieved in the humidifier group (n = 10) by using humidified and warmed gases at 40 degrees C, whilst in the oesophageal group (n = 10), an oesophageal heat exchanger was used to achieve active warming. Operating room temperature and relative humidity was standardised. Aural canal and skin temperatures (15 sites) were measured before induction of anaesthesia, at the end of surgery and one hour of recovery after anaesthesia. Mean skin temperatures were calculated for a weighted four and unweighted 15 points, and mean body heat were calculated to quantify the distribution of body heat. Core temperature decreased in the control and the oesophageal groups, but not in the humidifier group at the end of surgery; by mean values +/- SD of 1.9 degrees C +/- 0.6, 1.2 degrees C +/- 0.6 and 0.4 degree C +/- 0.2 degree C, respectively (P < 0.01). Mean skin temperature (MST15) decreased in the control group by 1.0 degree C +/- 1.0, but not in the actively warmed groups where the mean increased by 0.1 degree C +/- 1.4 and 0.2 degree C +/- 0.2 in the oesophageal and humidifier groups, respectively (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)