Invasive versus non-invasive cooling after in- and out-of-hospital cardiac arrest: a randomized trial

Abstract

Introduction: Mild induced hypothermia (MIH) is indicated for comatose survivors of sudden cardiac arrest (SCA) to improve clinical outcome. In this study, we compared the efficacy of two different cooling devices for temperature management in SCA survivors.

Methods: Between April 2008 and August 2009, 80 patients after survived in-hospital (IHCA) and out-of-hospital cardiac arrest (OHCA) were included in this prospective, randomized, single center study. Hypothermia was induced after randomization by either invasive Coolgard(®) cooling or non-invasive ArcticSun(®) surface cooling at 33.0 °C core body temperature for 24 h followed by active rewarming. The primary endpoint was defined as the efficacy of both cooling systems, measured by neuron-specific enolase (NSE) levels as a surrogate parameter for brain damage. Secondary efficacy endpoints were the clinical and neurological outcome, time to start of cooling and reaching the target temperature, target temperature-maintenance and hypothermia-associated complications.

Results: NSE at 72 h did not differ significantly between the 2 groups with 16.5 ng/ml, interquartile range 11.8-46.5 in surface-cooled patients versus 19.0 ng/ml, interquartile range 11.0-42.0 in invasive-cooled patients, p = 0.99. Neurological and clinical outcome was similar in both groups. Target temperature of 33.0 °C was maintained more stable in the invasive group (33.0 versus 32.7 °C, p < 0.001). Bleeding complications were more frequent with invasive cooling (n = 17 [43.6 %] versus n = 7 [17.9 %]; p = 0.03).

Conclusion: Invasive cooling has advantages with respect to temperature management over surface cooling; however, did not result in different outcome as measured by NSE release in SCA survivors. Bleeding complications were more frequently encountered by invasive cooling.