Clinical question / background:
- In patients with ROSC following cardiac arrest, does cooling patients to 33 degrees Celsius increase the rate of survival after resuscitation compared to cooling to 36 degrees Celsius?
Design:
- Unblinded, parallel-group, randomized, controlled trial
- 939 participants in 36 European and Australian centers
- Inclusion criteria:
- Witnessed arrest
- Unconscious at presentation
- Presumed cardiac origin of arrest
- Age >18
- More than 20 minutes of ROSC after resuscitation
- Exclusion criteria:
- No ROSC within 240 minutes of presentation
- Unwitnessed arrest with initial rhythm of asystole
- Suspected or known acute intracranial hemorrhage or stroke
- Body temperature <30 degrees Celsius
Intervention:
- Reduce core temperature (bladder temp) to 33 C or 36 C after ROSC. Maintain temperature goals for 28 hours, at which point allow for passive rewarming but maintain temperature below 37.5 C for 72 hours after ROSC
Control:
- None
*Both groups sedated with for 36 hours after ROSC by providers’ sedation agents of choice.
Primary endpoint:
- Mortality at the end of the trial
Secondary endpoints:
- Favorable neurologic outcome at 180 days after cardiac arrest defined by Pittsburgh cerebral performance categories (CPC) (1 good recovery, 2 moderate disability, 3 severe disability, 4 vegetative state, 5 death) or the Modified Rankin Criteria (0 representing no symptoms, 1 no clinically significant disability, 2 slight disability, 3 moderate disability, 4 moderately severe disability, 5 severe disability, and 6 death.)
- Mortality at 180 days
Results:
- No difference in mortality at the end of the trial
- 50% vs 48% (p=0.51)
- No difference in neurologic outcome at 180 days
- CPC 3-5: 54% vs 52% (p=0.78)
- Modified Rankin 4-6: 52% vs 52% (p=0.87)
- No difference in mortality at 180 days
- 48% vs 47% (p=0.92)
Take-home:
- No difference in mortality or neurologic outcomes in patients who are cooled to 33 C vs 36 C who present with witnessed arrest of presumed cardiac cause.
Weaknesses / Critiques
- Unblinded
- No control group
- Took nearly 12 hours to cool patients in this trial, compared to 4-6 in previous trials
- Possible that smaller subset of patients (i.e. those with initial shockable rhythm) could benefit from therapeutic hypothermia
Real World Application
- Consider hospital protocol and patient’s characteristics before initiating therapeutic hypothermia
Additional information:
EMRAP October 2015 – Targeted Temperature Management 1 Year later
www.emrap.org/episode/october/october
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