Introduction of an external noninvasive cooling device for effective implementation of Intensive Care Society standards post cardiac arrest

Introduction

Despite cardiac arrests accounting for 5.8% of admissions to intensive care, there is significant variation in the management and outcome of these patients in different units [1]. Randomised controlled trials have demonstrated that active cooling to 32 to 34°C for 12 to 24 hours after return of spontaneous circulation (ROSC) significantly improves the outcome of patients who have an out-of-hospital ventricular fibrillation arrest [2]. However there are a range of cooling techniques employed, and no trials have demonstrated that any particular system is superior [3].

Methods

All adult patients admitted to critical care following out-of-hospital cardiac arrest with Glasgow coma scale <9 after ROSC were included. The initial audit included nine patients admitted between August 2006 and March 2007 who were cooled primarily with standard methods such as ice packs/cooling pads. Performance was re-audited between August 2007 and December 2007 following the introduction of CritiCool, and included nine patients. Data were collected using an audit form, a computerised ICU patient database (CIMS) and clinical notes. We assessed neurological outcome at ICU discharge by calculating the cerebral performance category (CPC). The CPC is scored on a scale (0 to 5) where higher scores indicate worse functional impairment.

Results

Following introduction of the CritiCool there was improvement in the speed of cooling to the target temperature range (patients effectively cooled within 4 hours: 33% vs. 57%). There was also improved ability to maintain patients within the target temperature range over the 24-hour period (57% vs. 70%). There was also a trend towards improvement in the mean CPC score at ICU discharge from 3.4 to 2.3.

Conclusion

We have shown an improvement in the speed of cooling and target temperature maintenance. Our study also shows that the introduction of CritiCool correlated with an improvement in CPC. We suggest that more widespread use of noninvasive cooling devices may improve implementation of standards, avoid risks associated with invasive cooling devices and potentially improve neurological outcome.