Effectiveness of each target body temperature during therapeutic hypothermia after cardiac arrest.

Purpose: According to the 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation, unconscious adult patients with a return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest should be cooled to 32°C to 34°C for 12 to 24 hours. However, it is unclear which target temperature is more adequate. In this study, we prospectively evaluated the outcome and adverse effects following 3 target temperatures (32°C, 33°C, and 34°C) during therapeutic hypothermia with ROSC after out-of-hospital cardiac arrest.

Methods: This is a prospective study of patients with ROSC (>24 hours) after out-of-hospital cardiac arrest who were admitted to the intensive care unit in a tertiary hospital and underwent therapeutic hypothermia during a 22-month period between March 2007 and December 2008.

Results: Sixty-two patients were included. The number of male patients was 44. The mean (SD) ages of the patients was 54.61 (2.002) years. There were 13, 22, and 28 patients who were enrolled in the target temperatures (32°C, 33°C, and 34°C, respectively). There were no significant differences after each target temperature with respect to mortality and neurologic outcomes. Regarding adverse effects, hypotension during the maintenance of therapeutic hypothermia significantly increased when the target temperature was 32°C (P = .023). Based on multivariate analysis, hypotension during the maintenance of therapeutic hypothermia was increased more than 6 times at 32°C compared with 33°C (odds ratio, 6.800; 95% confidence interval, 1.428-32.373).

Conclusion: When performing therapeutic hypothermia in patients with ROSC after an out-of-hospital cardiac arrest, the target temperature would be set to 33°C or 34°C, rather than 32°C. Further multicenter randomized controlled studies may be needed in the future.