Intended for healthcare professionals

Head To Head

Does the evidence support the use of mild hypothermia after cardiac arrest? No

BMJ 2011; 343 doi: (Published 23 September 2011) Cite this as: BMJ 2011;343:d5889
  1. Andrew P Walden, consultant in critical care medicine1,
  2. Niklas Nielsen, consultant in critical care medicine2,
  3. Matt P Wise, consultant in critical care medicine 3
  1. 1Intensive Care, Royal Berkshire Hospital, Reading, UK
  2. 2Department of Anaesthesiology and Intensive Care, Helsingborg Hospital, Helsingborg, Sweden
  3. 3Adult Critical Care, University Hospital of Wales, Cardiff CF14 4XW, UK
  1. Correspondence to: M P Wise mattwise{at}

Several guidelines recommend hypothermia for comatose patients who have had a cardiac arrest outside hospital. Jerry Nolan and Jasmeet Soar (doi:10.1136/bmj.d5830) believe the data support this advice, but Andrew Walden, Niklas Nielsen, and Matt Wise question the quality of the evidence

Historically, critical care physicians had a nihilistic approach towards patients who remained unconscious after a cardiac arrest outside hospital. This changed with the publication of two randomised clinical trials of mild induced hypothermia (32-34°C) that showed neuroprotection.1 2 Subsequently this treatment has been embraced by the International Liaison Committee on Resuscitation, European Resuscitation Council, American Heart Association, and, most recently, the National Institute for Health and Clinical Excellence (NICE).

Animal models of cardiac arrest showed that mild hypothermia improved neurological outcome,3 and these data were supported by small observational studies in patients. Clinical trials to determine whether this treatment benefited unconscious patients after cardiac arrest were therefore fitting. However, neither the above randomised trials1 2 nor subsequent studies4 provide sufficiently robust data to justify the conclusion that cooling to 32-34°C should be used after cardiac arrest outside hospital.

Evidence from clinical trials

A search for the terms “cardiac arrest” and “hypothermia” …

View Full Text

Log in

Log in through your institution


* For online subscription