A comparison of the effects of phosphodiesterase III inhibitors, milrinone and olprinone, in infant corrective cardiac surgery

Background: Clinical characteristics of phosphodiesterase (PDE) III inhibitors, milrinone and olprinone, is not fully understood in infants. We therefore retrospectively examined the hemodynamics, metabolism, and oxygenation of two different PDE III inhibitors in infants undergoing radical correction of ventricular septal defect with pulmonary hypertension. Methods: Twenty-six infants with pulmonary hypertension undergoing ventricular septum defect repair were retrospectively allocated to milrinone group (n=13) and olprinone group (n=13). Hemodynamic parameters, acid-base balance, oxygenation and postoperative mechanical ventilation period were compared between the two groups at induction of anesthesia, weaning from cardiopulmonary bypass and the end of the surgery. Results: The patients' mean age was 4.4±2.5 months. Demographic data were almost similar between the two groups. Milrinone and olprinone were administered at the rates of 0.5 and 0.3 μg·kg^-1· min^-1 at the end of surgery, respectively. Hemodynamic variables, acid-base balance, Pa_O2/FI_O2 ratio and mechanical ventilation period were not significantly different between the two groups. No adverse side effects were observed during the study period. Conclusions: The effects of the PDE III inhibitors, milrinone and olprinone, on hemodynamic parameters, acid-base balance and oxygenation were similar in these infants. Both milrinone and olprinone could be used safely in infant cardiac surgery.