PURPOSE: To determine changes in surface body temperatures after local cooling of different regions in comatose adult survivors of cardiac arrest in the maintenance phase of targeted temperature management (TTM).
MATERIALS AND METHODS: We included six patients sedated to Ramsey Sedation Score 6 and without neuromuscular blocking agents during imaging. We obtained IR images (FLIR SC620, FLIR Systems, Wilsonville, Oregon, USA) of the head, thorax, abdomen and legs before and after an ice pack was placed on the skin. Ice pack covered 2% of body surface area (BSA) in the head region, and 9% in other regions. After 5 min the ice pack was removed and IR images of each region were obtained in 1 min intervals for 5 min.
RESULTS: Average maximal surface temperatures of the head, thorax, abdomen, and legs before local cooling were significantly lower compared to core body temperature measured by the Foley catheter (34.25±1.57°C) at 30,78±3,01°C, 30.67±2.82°C, 30.48±2.02°C and 28.00±3.73°C, respectively (all p values<0.005). There was no correlation between BSA and cooling rate (r=0.001, p=0.997), and a negative correlation between BSA and rewarming rate (r=-0.54, p=0.006). There were no significant differences in rewarming rate between head (2.06±0.34°C/min), thorax (1.6±0.37°C/min), and abdomen (1.68±0.24°C/min), and a significantly faster rewarming rate when comparing other body regions with legs (0.81±0.43°C/min, all p values<0.03).
CONCLUSIONS: Surface body temperature measured anywhere cannot be used to estimate core body temperature. In spite of coma after cardiac arrest and drug-induced sedation, a marked difference exists in thermoregulation of different body regions, with central regions rewarming faster compared to periphery after local cooling.

1 - Changes of Surface Body Temperatures after Local Cooling in Survivors of Cardiac Arrest during the Maintenance Phase of TTM