Non-invasive continuous cerebral temperature monitoring in patients treated with mild therapeutic hypothermia: An observational pilot study

Abstract

Aim of the study To investigate if body temperature as measured with a prototype of a non-invasive continuous cerebral temperature sensor using the zero-heat-flow method to reflect the oesophageal temperature (core temperature) during mild therapeutic hypothermia after cardiac arrest. Methods In patients over 18 years old with restoration of spontaneous circulation after cardiac arrest, a temperature sensor that uses the zero-heat-flow principle was placed on the forehead during the periods of cooling and re-warming. This temperature was compared to oesophageal temperature as the primary temperature-monitoring site. To assess agreement, we used the Bland–Altman approach and Lin's concordance correlation coefficient. Results From September 2008 to April 2009, data from 19 patients were analysed. The median time from restoration of spontaneous circulation until temperature sensor application was 53 min (interquartile range, 31; 96). All sensors were removed when a core temperature of 36 °C was reached. These measurements were in agreement with oesophageal temperature measurements. No allergic reaction, rash or other irritation occurred on the skin around or under the probes. Bland–Altman results showed a bias of −0.12 °C and 95% limits of agreement of −0.59 and +0.36 °C. Lin's concordance correlation coefficient was 0.98. Conclusions Body temperature measurements using a non-invasive continuous cerebral temperature sensor prototype that uses the zero-heat-flow method accurately reflected oesophageal temperature measurements during mild therapeutic hypothermia in patients with restoration of spontaneous circulation after cardiac arrest.