Milrinone Combined with Vasopressin Improves Cardiac Index after Cardiopulmonary Resuscitation in a Pig Model of Myocardial Infarction

Background: Milrinone used for acute cardiac insufficiency could be of interest during cardiopulmonary resuscitation because of its positive inotropic effects. In this study, the combination of milrinone-vasopressin was compared with epinephrine and vasopressin, as well as with the combination of epinephrine-vasopressin, in reference to hemodynamics. Methods: Thirty-two pigs underwent ligation of the circumflex coronary artery and induction of ventricular fibrillation lasting for 4 min. Cardiopulmonary resuscitation was performed after randomization to one of four groups: epinephrine (30-μg/kg bolus), vasopressin (0.4-U/kg bolus), epinephrinevasopressin (15-μg/kg epinephrine bolus, 0.2-U/kg vasopressin bolus), or milrinone-vasopressin (0.4-U/kg vasopressin bolus, 50-μg/kg milrinone bolus over 5 min and a continuous infusion of 0.4 μg · kg -1 · min -1 ). The hemodynamic variables were measured before cardiopulmonary resuscitation as well as 4, 8, 15, and 30 min after return of spontaneous circulation. Results: All animals were resuscitated successfully. The animals of the milrinone-vasopressin group displayed significantly (P < 0.05) higher cardiac index values (30 min after return of spontaneous circulation: epinephrine, 65.8 ± 13.2; vasopressin, 70.7 ± 18.3; epinephrine-vasopressin, 69.1 ± 36.2; milrinone-vasopressin, 120.7 ± 34.8 ml · min -1 · kg -1 ) without a decrease in mean arterial pressure or coronary perfusion pressure. Conclusions: The combination of vasopressin-milrinone as compared with epinephrine during cardiopulmonary resuscitation leads to an improved cardiac index without relevant decrease of mean arterial pressure or coronary perfusion pressure.