Objective: To investigate the relative effects of milrinone and nitric oxide on pulmonary and systemic hemodynamic responses in cardiac surgery patients with a history of pulmonary hypertension.
Design: Prospective and randomized.
Setting: University hospital.
Participants: Forty-five adult cardiac surgery patients.
Interventions: Cardiac surgery patients with pulmonary hypertension were randomly assigned to one of three study groups: Group 1 patients (n = 15) were treated with intravenous milrinone on separation from cardiopulmonary bypass, group 2 patients (n = 15) with 20 ppm of inhaled nitric oxide, and group 3 patients (n = 15) with 40 ppm of inhaled nitric oxide. Heart rate, right ventricular ejection fraction, and pulmonary vascular resistance were measured throughout the perioperative period at specific data points.
Measurements and main results: There were no significant differences in demographics, anesthesia, surgery, or baseline hemodynamics among the groups. The group receiving 40 ppm nitric oxide had a significantly higher (p<0.05) right ventricular ejection fraction on arrival in the intensive care unit (40% v. 30% for the milrinone group and 33% for the nitric oxide 20 ppm group). The milrinone group required significantly more phenylephrine in the intensive care unit (p<0.05).
Conclusions: Treatment of pulmonary hypertension in adult cardiac surgery patients with inhaled nitric oxide compared with milrinone is associated with lower heart rates, higher right ventricular ejection fraction, and a lower requirement for treatment with vasopressor agents.