It's so cold out there! Survival after out of hospital cardiac arrest with a good outcome is a rare event. Despite advances across other fronts in medicine, survival with an intact brain hadn't improved much in the last 50 years until someone tried post-arrest cooling. Previously, post-resuscitation efforts have been entirely supportive. Now, for comatose patients after vfib arrest, cooling the body to 34 degrees for 24 hours can nearly double the chance of recovery. Currently at UVa, we're cooling 3-4 patients a month (last month we did 7!).
But how do we cool patients? Everything has been tried. From ice bags, cold saline, irrigating bladder/stomach with cold fluids to cardiopulmonary bypass. All present technical and clinical challenges, not the least of which is that body vigorously defends its tightly regulated core temperature by increasing metabolic rate and shivering, usually requiring paralysis. Surface cooling is cumbersome and ineffective. Intravascular cooling (which we use) is expensive and risky. What if there was another way?
Researchers in toasty warm LA have published a trial using cannabanoid agonists in rats after resuscitation in vfib arrest. The results are very good news if you are a rat in a coma after vfib arrest: the drug appears to safely lower body temperature to ~34 degrees with no other major noted side effects. More importantly, the neurologic and functional outcome was significantly improved relative to controls. The idea may represent a new therapeutic class for a common and lethal problem for thousands of Americans.
Finally, a quote from recent editorial on the new findings by Samuel Tisherman, "From the campaign 20 yrs ago (showing a frying pan representing marijuana and an egg representing your brain), to current controversies regarding legal medical uses, marijuana has a long history of capturing our interest. Wouldn't it be cool if a derivative actually improves brain function rather than frying it?"
Sun S, Tang W, Song F, et al: Pharmacologically induced hypothermia with cannabinoid receptor agonist WIN55, 212-2 after cardiopulmonary resuscitation. Crit Care Med 2010; 38:2282–2286
Bernard SA, Gray TW, Buist MD, et al: Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med 2002; 346:557–563