Comparison of two different loading doses of milrinone for weaning from cardiopulmonary bypass Comparison of two different loading doses of milrinone for weaning from cardiopulmonary bypass
Faculty of Medicine and Health Sciences
Publication type
Philadelphia, Pa ,
Human medicine
Source (journal)
Journal of cardiothoracic and vascular anesthesia. - Philadelphia, Pa
9(1995) :3 , p. 264-271
Target language
English (eng)
Full text (Publishers DOI)
University of Antwerp
Objective: To compare the hemodynamic effects, pharmacokinetic profiles, and the need for vasoactive agents between a low (20 mu g/kg during 15 minutes [group 1; n = 10]) and a high (40 mu g/kg during 15 minutes [group 2; n = 10]) loading dose of milrinone. Design: Prospective, randomized, double-blind. Setting: University hospital. Participants: Twenty patients scheduled for elective coronary artery surgery. Interventions: Weaning from CPB was achieved using a strict protocol. After atrioventricular pacing at 90 beats per minute and preload optimalization, a first weaning attempt was started with only calcium and nitroglycerin as support. If this attempt was unsuccessful (cardiac index < 2L/min/m(2)), CPB was reinitiated and weaning level 2 was prepared, consisting of inotropic support with milrinone. Patients received either the low (group 1) or the high (group 2) loading dose of milrinone. After the end of the loading dose, a continuous infusion of milrinone of 0.5 mu g/kg/min was started in both groups. Measurements and Main Results: Both groups were comparable regarding preoperative and intraoperative data. Hemodynamic data were comparable in both groups at each time of measurement (p = 0.941). The need for vasoactive medication (norepinephrine [NE]) in order to keep mean arterial pressure greater than or equal to 50 mm Hg was significantly higher in group 2 (p = 0.004). Need for NE during the loading infusion was 9.6 +/- 4.9 mu g (mean +/- SEM) in group 1 and 41.6 +/- 7.6 mu g in group 2 (p = 0.004). Need for NE during the immediate post-CPB period was also higher in group 2 (16.0 +/- 10.4 mu g in group 1 and 232.5 +/- 82.8 mu g in group 2 in = 0.002)). Plasma clearance of milrinone after CPB was less in both groups than in healthy volunteers. However, clearance of milrinone was significantly higher in group 2 (p = 0.006), and consequently, half-life of milrinone was significantly less in group 2 (p = 0.007). Conclusions: The present results demonstrate that when milrinone is used during weaning from CPB, a loading dose of 20 mu g/kg provided to similar hemodynamic support a loading dose of 40 mu g/kg. The need for vasoconstrictive medication was significantly less in the group with the low loading bose. Copyright (C) 1995 by W.B. Saunders Company