TTM Trial Investigators: Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest

Nielsen et al for the TTM Trial Investigators. NEMJ 2013;369:2197-206

Clinical Question

-  In adults that suffer an out-of-hospitals (OOH) cardiac arrest of presumed cardiac cause, does induced therapeutic hypothermia targeting 36°C compared to 33°C reduce mortality or reduce neurological deficit?

N = 950, 36 ICUs in Europe and Australia

Authors’ Conclusions

-  This trial does not provide evidence that targeting a body temperature of 33°C confers any benefit for unconscious patients admitted to the hospital after out-of-hospital cardiac arrest, as compared with targeting a body temperature of 36°C.

The Bottom Line

-  This trial has not shown any benefit of therapeutic hypothermia at 33°C over 36°C after OOH cardiac arrest. Not everyone agrees this is the same as “36°C is equivalent to 33°C”.
-  My conclusion: if cooling a patient to the conventional 33°C induces unwanted effects, aim for 36°C instead and it probably will make no difference to the patient’s outcome.