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Table 1 Comparison of two recent trials of hypothermia in cardiac arrest

From: Hypothermia and neurologic outcome in patients following cardiac arrest: should we be hot to cool off our patients?

Study information and statistical significance European [1] Australian [2]
Type of study Randomized: normothermia versus hypothermia Randomized: normothermia versus hypothermia
   Multicentered, with nine centers in five countries Four accepting emergency departments
   Blinded outcome Not blinded for treatment or outcome
Number of patients 275 Total 77 Total
   138 Normothermia 34 Normothermia
   137 Hypothermia 43 Hypothermia
Criteria Inclusion Witnessed arrest Initial rhythm VF
   Arrest secondary to VF Continued coma after ROSC
   Age 18–75 years Age: women >50 years; men >18 years
   <60 min to ROSC  
  Exclusion Temp <30°C Cardiogenic shock (SBP <90 mmHg despite epinephrine)
   Pregnant Pregnant
   Awake before randomization Other causes of coma
   MAP <60 mmHg for >30 min ICU bed unavailable
   Hypoxemia for >15 min  
   Terminal illness  
   Unavailable for follow-up  
   Enrolment in other study  
Comparability of hypothermia and normothermia groups The normothermia group had higher rates of coronary artery disease and diabetes mellitus The normothermia group had a higher percentage of bystander-performed cardiopulmonary resuscitation
Cooling Temperature used 32–34°C (bladder temperature) 33°C
  Mechanism Cool air circulating device and ice packs Ice packs
  Time to start Mean 105 min Cooling began prehospital at a rate of 0.9°C/hour
  Duration 24 hours 12 hours
Rewarming   Passive over 8 hours Passive
Side effects   No statistical difference between the two groups No statistical difference between the two groups
End-points Primary Favorable neurologic outcome at 6 months after arrest Discharge to home or rehabilitation
  Secondary (1) Mortality within 6 months Side effects of hemodynamic, biochemical, or hematological instability
   (2) Complications within 7 days  
Outcomes   Hypothermia: favorable outcome in 75 patients (55%) Hypothermia: favorable outcome in 21 patients (49%)
   Normothermia: favorable outcome in 54 patients (39%) Normothermia: favorable outcome in 9 patients (26%)
Statistical significance of the outcomes P = 0.009 P = 0.046
  1. The table summarizes some of the features of the two recent studies that examined the neuroprotective advantage of hypothermia in treatment of cardiac arrest. ICU, intensive care unit; ROSC, restoration of spontaneous circulation; VF, ventricular fibrillation.