Clinical paperThe impact of therapeutic hypothermia on neurological function and quality of life after cardiac arrest☆
Introduction
The annual incidence of out-of-hospital cardiac arrest (OHCA) in Copenhagen is about 45 per 100,000 inhabitants, with approximately 6% being alive at 30 days depending on initial rhythm, whether OHCA was witnessed, and time to initiation of basic life support.1, 2
Therapeutic hypothermia, with a core temperature of 32–4 °C, for 12–24 h after return of spontaneous circulation (ROSC) has been shown to improve survival and neurological function, assessed as Cerebral Performance Category (CPC).3, 4 Based on these two studies, the International Liaison Committee on Resuscitation recommends use of therapeutic hypothermia in comatose survivors of OHCA.5 However, it is important to realize that long-term cognitive function and quality of life are other relevant endpoints to consider in the evaluation of the impact of these new treatment strategies.
The present prospective cohort study assesses the long-term outcome in comatose patients resuscitated from OCHA, including standardized evaluation of cognitive function, and quality of life before and after implementation of therapeutic hypothermia.
Section snippets
Study area and population
Copenhagen, the capital of Denmark covers 97 km2 and has approximately 596,000 inhabitants increasing during daytime by 20%. Patients suffering from OHCA in central Copenhagen area are treated by the Mobile Emergency Care Unit (MECU), which is called to the scene. The MECU system is described elsewhere.1
We compared patients admitted in the period or June 1st 2004 to May 31st 2006 (intervention period) with patients admitted in the previous 2-year period, June 1st 2002 to May 31st 2004 (control
Results
In total, 79 patients were admitted to the ICU during the intervention period vs. 77 patients in the control period (Fig. 1). No differences in demographic data or concurrent diseases were found between the two periods (Table 1).
Twenty-seven and 21 patients had non-shockable rhythms in the intervention and control period, respectively. Six month survival among these patients was 7/27 (26%) and 2/21 (10%) respectively (Fig. 1).
In the intervention period, 52 (66%) patients had VF/VT as initial
Discussion
Implementation of therapeutic hypothermia was associated with improved cerebral outcome at hospital discharge in patients admitted comatose after OCHA with VF/VT. Perceived quality of life tended to improve in 2 out of 8 variables after implementation of therapeutic hypothermia, but this was not statistically significant. No significant difference in survival or cognitive status could be detected at follow-up.
Conclusion
Implementation of therapeutic hypothermia after out of hospital cardiac arrest was associated with improved cerebral outcome measured by CPC at discharge from hospital in patients with VT/VF, but not with survival. Improvement in cognitive status or quality of life was not detected at long-term follow-up.
Conflict of interest
The authors have no conflicts of interest to disclose.
Acknowledgements
Ane Loof Johansen RN and Charlotte Kruse RN are acknowledged for their substantial efforts in data collection for this study.
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A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2008.09.009.