Cardiac arrest: hypothermia led to more comatosed patients having a good functional outcome

Clinical bottom line (level 2b)

  1. Patients in a coma following an out-of-hospital cardiac arrest who received treatment with hypothermia compared with normothermia were more likely to have a good functional outcome (NNT = 2 at days) , but not clearly less likely to die.
Bernard et al: N Engl J Med 2002; 346 : 557-563
Expires May 2004

The study

Single-blinded ?concealed quasi-randomised trial with intention-to-treat
Setting: 4 emergency departments, acute hospitals, Australia

77 patients (aged 41 to 89; mean 66, 68% male) comatosed following an out-of-hospital cardiac arrest

Excluded if
  • initial rhythm not ventricular fibrillation
  • men ageaged <, women aged < 50 18
  • cardiogenic shock (systolic bp < 90 mmHg despite epinephrine infusion)
  • other possible cause for coma (drug overdose, head trauma or stroke)
  • no intensive bed available

Control Group: (n = 34, 34 analysed): normothermia
Experimental Group: (n = 43, 43 analysed): hypothermia: removal of clothes + addition of icepacks to achieve a core temperature of 33 C maintained for 12 hours after arrival in hospital, after which patients were gradually rewarmed.
All patients were sedated and paralysed using midazolam and vecuronium. Thrombolysis was given if required.
100% followed for - days

The evidence

Outcome Time to outcome CER EER RRR
(95% CI)		 ARR
(95% CI)		 NNT
(95% CI)
discharged home or to rehabilitation facility days 21
(61.8%)		 9
(20.9%)		 66%
(36% to 82%)		 40.8%
(20.5% to 61.2%)		 2
(2 to 5)
death days 23
(67.7%)		 22
(51.2%)		 24%
(-10% to 48%)		 16.5%
(-5.21% to 38.2%)		 6
(NNT = 3 to infinity;
NNH = 19 to infinity)

Citation

  1. Bernard SA, Gray TW, Buist MD, et al: treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med 2002; 346 : 557-563
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Contributor: Chris Ball, May 2002
Reviewer:

Clinical Question.
Patient coma following out-of-hospital cardiac arrest
Intervention or Exposure hypothermia
Comparison normothermia
Outcome good functional outcome, death