Cardiopulmonary resuscitation during severe hypothermia in pigs: Does epinephrine or vasopressin increase coronary perfusion pressure?

The American Heart Association does not recommend epinephrine for managemen t of hypothermic cardiac arrest if body core temperature is below 30 degree s C. Furthermore, the effects of vasopressin administration during hypother mic cardiac arrest are totally unknown. This study was designed to assess t he effects of vasopressin and epinephrine on coronary perfusion pressure in a porcine model during hypothermic cardiac arrest cardiopulmonary resuscit ation (CPR). Pigs were surface-cooled until their body core temperature was 26 degrees C. After 30 min of untreated cardiac arrest, followed by 3 min of basic life support CPR, 15 animals were randomly assigned to receive, at 5-min intervals, either vasopressin (0.4, 0.4, and 0.8 U/kg; n = 5), epine phrine (45, 45, and 200 mu g/kg; n = 5), or saline placebo (n = 5). Compare d with epinephrine, mean +/- SEM coronary perfusion pressure was significan tly higher (P < 0.05) 90 s and 5 min after the first (35 +/- 4 vs 22 +/- 3 mm Hg and 37 +/- 2 vs 16 +/- 2 mm Hg) and the second vasopressin administra tion (40 +/- 5 vs 26 +/- 5 mm Hg and 36 +/- 5 vs 18 +/- 2 mm Hg, respective ly). After the third drug administration, coronary perfusion pressure in th e epinephrine group increased dramatically and was comparable to vasopressi n. In the saline placebo group, coronary perfusion pressure was significant ly lower (P < 0.05) than in the vasopressin and epinephrine groups. Six ani mals treated with epinephrine or vasopressin had transient return of sponta neous circulation, whereas all placebo animals died (P < 0.05). During CPR in severe hypothermia, administration of both vasopressin and epinephrine r esulted in significant increases in coronary perfusion pressure when compar ed with placebo. Implications: Our study was designed to assess the effects of vasopressin and epinephrine in a porcine model simulating cardiac arres t during severe hypothermia. This study demonstrates that the administratio n of both emergency drugs results in an increased perfusion pressure in the heart.