Article Citation: Holzer M, et al. “Mild Therapeutic Hypothermia to Improve the Neurologic Outcome After Cardiac Arrest”. The New England Journal of Medicine. 2002. 346(8):549-556.
What we already know about the topic: prelim studies demonstrated that lowering brain temp s/p cardiac arrest improves neurologic recovery.
Why this study is important: Hypoxemic brain injury is the most common cause of death in patients s/p cardiac arrest and lowering brain temperature reduces risk of neurologic injury.
Brief overview of the study:
- Study design: multicenter, unblinded RCT in 9 centers in 5 European countries from 1996-2000 with intention to treat
- N = 275
- Hypothermia n = 137
- Normothermia n = 138
- Patients were randomly assigned to hypothermia and normothermia groups.
- Hypothermia: target bladder temp 32-34 within 4h after ROSC with external cooling device and temp maintained for 24h from start of cooling followed by passive rewarming to temp > 36
- Neurologic outcome assessed using Pittsburgh cerebral performance scale:
1: good recovery
2: moderate disability
3: severe disability
4: vegetative state
1&2 = favorable outcome.
Primary outcome: favorable neurologic outcome within 6 months: 55% (hypothermia) vs 39% (normothermia)
Limitations: it was a small trial where physician were not blinded to treatment assignments.
Take home points: in pts with VF or pulseless VT arrest, mild therapeutic hypothermia (32-34 degree celcius) improved neurologic outcomes and reduced mortality at 6 months.
TTM trial in 2013 found no difference between temp targets of 33 and 36 for all cause mortality or cognitive benefit. So maybe avoiding hyperthermia is the key here?