How Cooling May Help: decrease inflammatory cascade, aborts cell death, reducing free radicals, decreases cerebral metabolism.
Tx of Comatose Survivors of Out-of-Hospital Cardiac Arrest with Induced Hypothermia; Bernard trial. 77 pts only; only v-fib arrest. Normal vs keeping less than 33C. Absolute mortality beneift of 16%. 23% absolute difference in patients with ‘good’ outcome.
HACA Trial – 275 pts; Normal vs less than 33C. Absolute benefit of 14% mortality, 16% absolute difference in patients with ‘favorable’ outcome. 1/10 NNT.
Mild Therapeutic Hypothermia to Improve the Neurologic Outcome after Cardiac Arrest, Nielson. TTM Trial – 939 pts (most vfib/vtach), keep above 33C and the other was below 36C. No control. No statistical differnce between 33 vs 36 for mortality/neuro outcome.
Contraindications: Rapid and complete recovery (patient following commands), illneses that preclude meaningful recovery (comfort care); DNR orders. Minor: know presence of cold agglutinins; Active or high risk of bleeding; > 12 hours after cardiac arrest.
Induction: Cold IVF, Surface cooling methods (Artic sun, cooling blanket). Endovascular regulation more precise and faster.
Shivering: increases systemic metabolic demand. Tx: skin counter-warming; magnesium (4g IV); sedation (versed/propofol/fentanyl), consider buspar with precedex. Last resort paralysis.
Phases of TH: Immediate cooling, maintain and monitor, then rewarm at 0.2C/hr and get into normothermia avoiding fever.
Resuscitation Following Cardiac Arrest, Christina Tupe, The Crashing Patient Conference 2015. http://cloud.emedhome.com/cme/cme_45768_hi.mp4?iframe=true&width=920&height=470