CARDIOVASCULAR FUNCTION DURING THE POSTRESUSCITATION PHASE AFTER CARDIAC-ARREST IN PIGS - A COMPARISON OF EPINEPHRINE VERSUS VASOPRESSIN

Objective: The administration of vasopressin during cardiopulmonary re suscitation (CPR) provides significantly more vital organ blood flow w hen compared with epinephrine during cardiac arrest in pigs. The effec ts or this potent vasoconstrictor on postresuscitation cardiovascular function remain unknown, The purpose of this study was to compare the effects of vasopressin and epinephrine on cardiovascular function in t he postresuscitation phase after CPR, Design: Prospective, randomized, experimental study, Setting: University research laboratory, Subjects : Domestic pigs, 12 to 14 wks of age, Interventions: Sixteen pigs were randomly allocated to receive either 0.045 mg/kg of epinephrine or 0. 4 U/kg of vasopressin after 4 mins of cardiac arrest, Measurements and Main Results: Hemodynamics, left ventricular contractility, and myoca rdial blood flow were measured for an interval of 240 mins after succe ssful CPR, Differences between animals treated with epinephrine vs, va sopressin were most pronounced 15 mins after restoration of spontaneou s circulation, At this time, mean aortic pressure was 64 +/- 6 (SEM) m m Hg in the epinephrine group and 84 +/- 6 mm Hg (p < .05) in the vaso pressin group, Systemic vascular resistance was 1285 +/- 72 dyne . sec /cm(5) in the epinephrine group and 2314 +/- 130 dyne . sec/cm(5) (p < .001) in the vasopressin group. Cardiac index was 140 +/- 9 mL/min/kg in animals treated with epinephrine and 99 +/- 9 mL/min/kg (p < .01) in animals treated with vasopressin. Myocardial contractility (dp/ dt( max)/P) was 52.8 +/- 3.4/sec with epinephrine as compared with 36.3 +/ - 2.9 sec(-1) (p < .01) with vasopressin, Left ventricular epicardial blood flow was 241 +/- 35 mL/min/100 g with epinephrine and 142 +/- 22 mL/min/100 g (p < .05) with vasopressin, Four hours after CPR, no sig nificant differences were observed between groups, Conclusions: In the early postresuscitation phase, vasopressin provided higher systemic b lood pressures and there was a reversible depressant effect on myocard ial function when compared with epinephrine. Overall cardiovascular fu nction was not irreversibly or critically impaired after the administr ation of vasopressin in this pig model of cardiac arrest.