Elsevier

Resuscitation

Volume 80, Issue 2, February 2009, Pages 171-176
Resuscitation

Clinical paper
The impact of therapeutic hypothermia on neurological function and quality of life after cardiac arrest

https://doi.org/10.1016/j.resuscitation.2008.09.009Get rights and content

Abstract

Aims

To assess the impact of therapeutic hypothermia on cognitive function and quality of life in comatose survivors of out of Hospital Cardiac arrest (OHCA).

Methods

We prospectively studied comatose survivors of OHCA consecutively admitted in a 4-year period. Therapeutic hypothermia was implemented in the last 2-year period, intervention period (n = 79), and this group was compared to patients admitted the 2 previous years, control period (n = 77). We assessed Cerebral Performance Category (CPC), survival, Mini Mental State Examination (MMSE) and self-rated quality of life (SF-36) 6 months after OHCA in the subgroup with VF/VT as initial rhythm.

Results

CPC in patients alive at hospital discharge was significantly better in the intervention period with a CPC of 1–2 in 97% vs. 71% in the control period, p = 0.003, corresponding to an adjusted odds ratio of a favourable cerebral outcome of 17, p = 0.01. No significant differences were found in long-term survival (57% vs. 56% alive at 30 months), MMSE, or SF-36. Therapeutic hypothermia (hazard ratio: 0.15, p = 0.007) and bystander CPR (hazard ratio 0.19, p = 0.002) were significantly related to survival in the intervention period.

Conclusion

CPC at discharge from hospital was significantly improved following implementation of therapeutic hypothermia in comatose patients resuscitated from OCHA with VF/VT. However, significant improvement in survival, cognitive status or quality of life could not be detected at long-term follow-up.

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.

References (25)

  • Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest

    N Engl J Med

    (2002)
  • J.P. Nolan et al.

    Therapeutic hypothermia after cardiac arrest: an advisory statement by the advanced life support task force of the International Liaison Committee on Resuscitation

    Circulation

    (2003)
  • Cited by (109)

    View all citing articles on Scopus

    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.

    View full text