Developing a vasopressor combination in a pig model of adult asphyxial cardiac arrest

Background-The purpose of this study was to investigate the effects of vaso pressin versus epinephrine, and both drugs combined, in a porcine model of simulated adult asphyxial cardiac arrest. Methods arid Results-At approximate to7 minutes after the endotracheal tube had been clamped, cardiac arrest was present in 24 pigs and remained untre ated for another 8 minutes. After 4 minutes of basic life support cardiopul monary resuscitation, pigs were randomly assigned to receive, every 5 minut es, either epinephrine (45, 200, or 200 mug/kg; n=6); vasopressin (0.4, 0.8 , or 0.8 U/kg; n=6); or epinephrine combined with vasopressin (high-dose ep inephrine/vasopressin combination, mug/kg and U/kg: 45/0.4, 200/0.8, or 200 /0.8; n=6; optimal-dose epinephrine/vasopressin combination, 45/0.4, 45/0.8 , or 45/0.8; n=6). Mean SEM coronary perfusion pressure was significantly ( P <0.05) higher 90 seconds after high- or optimal-dose epinephrine/vasopres sin combinations versus vasopressin alone and versus epinephrine alone (37 +/- 10 versus 25 +/-7 versus 19 +/-8 versus 6 +/-3 mm Hg; 42 +/-6 versus 40 +/-5 versus 21 +/-5 versus 14 +/-6 mm Hg; and 39 +/-6 versus 37 +/-4 versu s 9 +/-3 versus 12 +/- 14 mm Hg, respectively). Six of 6 high-dose. 6 of 6 optimal-dose vasopressin/epinephrine combination, 0 of 6 vasopressin, and 1 of 6 epinephrine pigs had return of spontaneous circulation (P<0.05). Conclusions-Epinephrine combined with vasopressin, but not epinephrine or v asopressin alone, maintained elevated coronary perfusion pressure during ca rdiopulmonary resuscitation and resulted in significantly higher survival r ates in this adult porcine asphyxial model.