Endothelin-1 vasoconstriction during swine cardiopulmonary resuscitation improves coronary perfusion pressures but worsens postresuscitation outcome

Background-Vasoconstriction during cardiopulmonary resuscitation (CPR) impr oves coronary perfusion pressure (CPP) and thereby outcome. The combination of endothelin-1 (ET-1) plus epinephrine improved CPP during CPR compared w ith epinephrine alone in a canine cardiac arrest model. The effect of the c ombination on outcome variables, such as successful resuscitation and survi val, has not been investigated. Methods and Results-Twenty-seven swine were randomly provided with 1 mg epi nephrine (Epi group) or 1 mg epinephrine plus 0.1 mg ET-1 (ET-1 group) duri ng a prolonged ventricular fibrillatory cardiac arrest. ET-1 resulted in su bstantially superior aortic relaxation pressure and CPP during CPR. These h emodynamic improvements tended to increase initial rates of restoration of spontaneous circulation (8 of 10 versus 8 of 17, P=0.12). However, continue d intense vasoconstriction from ET-1 led to higher aortic diastolic pressur e and very narrow pulse pressure after resuscitation. The mean pulse pressu re: 1 hour after resuscitation was 7+/-8 mm Hg with ET-1 versus 24+/-1 mm H g with Epi, P<0.01. Most importantly, the postresuscitation mortality was d ramatically higher in the ET-1 group (6 of 8 versus 0 of 8 in the Epi group , P<0.01). Conclusions-These data establish that administration of ET-1 during CPR can result in worse postresuscitation outcome. The intense vasoconstriction fr om ET-1 improved CPP during CPR but had detrimental effects in the postresu scitation period.