Elsevier

Resuscitation

Volume 77, Issue 3, June 2008, Pages 331-338
Resuscitation

Clinical paper
Out-of-hospital surface cooling to induce mild hypothermia in human cardiac arrest: A feasibility trial

https://doi.org/10.1016/j.resuscitation.2008.01.005Get rights and content

Summary

Aim

The earliest initiation of mild hypothermia after resuscitation from cardiac arrest is crucial. This study aimed to evaluate the feasibility and safety of out-of-hospital surface cooling in such cases.

Methods

Cooling pads stored below 0 °C in the ambulance were applied as soon as possible after restoration of spontaneous circulation in the out-of-hospital setting. This continued in the emergency department until an oesophageal temperature of 34 °C was reached, when the pads were removed. A target temperature of 33 °C was maintained for 24 h. Results are given as median and interquartile range.

Results

From September 2006 to January 2007, 15 victims of cardiac arrest were included. Cooling was initiated at 12 (8.5–15) min after restoration of spontaneous circulation. Oesophageal temperatures decreased from 36.6 (36.2–36.6) °C to 33 °C within 70 (55–106) min. Hospital admission was at 45 (34–52) min, with oesophageal temperatures of 35.4 (34.6–35.9)°C; the target 33 °C was achieved 50 (29–82) min after admission. No skin lesions were observed.

Conclusion

Non-invasive surface cooling immediately after resuscitation from cardiac arrest, in the out-of-hospital setting, proved to be feasible, fast and safe. Whether early cooling will improve neurological outcome needs to be determined in future studies.

Introduction

Sudden cardiac death is a major health concern, with evolving emergency care strategies.1, 2 Mild hypothermia has been one of the few measures that have been shown in several experimental and clinical studies to improve neurological outcome after cardiac arrest.3, 4, 5, 6, 7, 8 Animal data suggest that early induction of hypothermia is crucial in order to obtain its beneficial effect.9, 10, 11, 12 Therefore, the advanced cardiac life support guidelines recommend initiating mild therapeutic hypothermia ‘as soon as possible’.13

In recent years, non-invasive as well as invasive cooling methods for induction of mild hypothermia after resuscitation from cardiac arrest have been investigated.8, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 To clinically translate the results of animal studies9, 10, 11, 12 and to follow the guidelines,30 cooling methods are needed which are feasible, non-invasive, immediately applicable and available in the out-of-hospital setting to emergency medical service (EMS) providers. The efficacy and safety in the out-of-hospital setting of newly designed cooling pads for surface cooling of persons resuscitated after cardiac arrest are evaluated in this preliminary explorative study.

Section snippets

Materials and methods

This study was a collaboration between the Ambulance Service and the Department of Emergency Medicine of the Medical University in Vienna. Data of a sample of consecutive patients treated by the Ambulance Service after out-of-hospital cardiac arrest were collected, and cooling efficacy and safety of the new cooling pads (Emcoolspad®, Emcools, Vienna, Austria) were analysed. Protocols were approved by the local ethics committee, and for all participants the requirement of informed consent was

Results

Eight emergency medical service ambulances were equipped with the cooling pads. From October 2006 to January 2007, the ambulance staff attended 61 out-of-hospital cardiac arrests. ROSC was achieved in 32 (52%) cases, and 15 (25%) fulfilled the inclusion criteria for application of the cooling device. Patients who were excluded numbered three younger than 18 years, three conscious before any cooling, two with Tes <34 °C, two whose cardiac arrest occurred during transport and just before arrival

Discussion

Non-invasive surface cooling with cooling pads was a fast, feasible and safe method in the out-of-hospital setting for early induction of therapeutic hypothermia after non-traumatic cardiac arrest. The median time to reach a target temperature of 33 °C was 70 (55–106) min, which resulted in a cooling rate of 3.3 (2.0–4.0) °C/h. Target temperature was reached 50 (49–82) min after hospital admission. Apart from some minor skin irritation without any permanent damage or scar formation, no adverse

Conclusion

Non-invasive surface cooling with cooling pads in the out-of-hospital setting immediately after resuscitation from cardiac arrest proved feasible, fast and safe. Whether such early cooling improves neurological outcome, as compared with delayed cooling in hospital, needs to be determined in a prospective randomised trial.

Conflict of interest

Wilhelm Behringer is a co-founder and stockholder in Emcools AG.

Acknowledgements

On behalf of the Vienna Hypothermia After Cardiac Arrest (HACA) Study Group, the authors want to thank the participating paramedics and emergency physicians of the Ambulance Service of Vienna and the nurses of the Department of Emergency Medicine for their support of the study.

This project was funded in part by a grant from the Jubiläumsfonds of the Austrian National bank (no. 12121). Emcools AG, Vienna, Austria, provided the cooling device and technical and administrative support, but was not

References (42)

  • C. Callaway et al.

    Feasibility of external cranial cooling during out-of-hospital cardiac arrest

    Resuscitation

    (2002)
  • A. Kliegel et al.

    Cold simple intravenous infusions preceding special endovascular cooling for faster induction of mild hypothermia after cardiac arrest—a feasibility study

    Resuscitation

    (2005)
  • F.M. Al-Senani et al.

    A prospective, multicenter pilot study to evaluate the feasibility and safety of using the CoolGard System and Icy catheter following cardiac arrest

    Resuscitation

    (2004)
  • J.J. Vreede-Swagemakers et al.

    Out-of-hospital cardiac arrest in the 1990s: a population-based study in the Maastricht area on incidence, characteristics and survival

    J Am Coll Cardiol

    (1997)
  • Y. Leonov et al.

    Mild cerebral hypothermia during and after cardiac arrest improves neurologic outcome in dogs

    J Cereb Blood Flow Metab

    (1990)
  • P. Safar et al.

    Improved cerebral resuscitation from cardiac arrest in dogs with mild hypothermia plus blood flow promotion

    Stroke

    (1996)
  • P. Eisenburger et al.

    Therapeutic hypothermia after cardiac arrest

    Curr Opin Crit Care

    (2001)
  • M. Holzer et al.

    Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest

    N Engl J Med

    (2002)
  • S.A. Bernard et al.

    Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia

    N Engl J Med

    (2002)
  • M. Holzer et al.

    Hypothermia for neuroprotection after cardiac arrest: systematic review and individual patient data meta-analysis

    Crit Care Med

    (2005)
  • K. Kuboyama et al.

    Delay in cooling negates the beneficial effect of mild resuscitative cerebral hypothermia after cardiac arrest in dogs: a prospective, randomized study

    Crit Care Med

    (1993)
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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.2008.01.005.

    1

    The Vienna Hypothermia After Cardiac Arrest (HACA) Study Group: Jasmin Arrich; Alexander Auer; Kewan Bayegan; Wilhelm Behringer; Andreas Braunisch; Philip Eisenburger; Roman Fleischhackl; Monika Fusek; Oliver Geyer; Christoph Havel; Moritz Haugk; Herbert Heissenberger; Micheal Holzer; Andreas Janata; Alfred Kaff; Andreas Kliegel; Maria-Petra Krenn; Anton N Laggner; Johannes Lahmer; Heidrun Losert; Nina Richling; Eva Riedmüller; Kurt Schafellner.

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