Hemodynamic effects of morphine and nalbuphine in acute myocardial infarction

Hemodynamic effects of morphine and the new narcotic analgesic, nalbuphine, were compared in a randomized, double-blind study in 15 patients with acute myocardial infarction (11 men and four women, average age 56.2 yr) and normal group mean hemodvnamic,function. During a 1-hr evaluation the Hmodynamic effects were small but there were changes in several parameters. Morphine reduced heart rate (78 to 72 bpm, p < 0.01) and diastolic and mean arterial pressures (69 to 64 mm Hg, p < 0.05; and 91 to 84 nun Hg, p < 0.05); nalbuphine was associated with a decrease in heart rate (82 to 72 bpm, p < 0.01), decrease in cardiac index, which remained within the normal range (3.16 to 2.75 lminlinz, p < 0.01), and an increase in systemic vascular resistance (1,204 to 1,461 dynes · sec · cm^-5 p < 0.05). Neither drug altered systolic arterial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, stroke index, stroke work index, or pulmonary vascular resistance. Echocardiographic assessment revealed diminution of left ventricular mean velocity gf circumferential fiber shortening sifter nalbuphine (1.26 to 1.08 circlsec, p < 0.05). Both drugs induced small reductions in respiratory rate and arterial pH and increases in PA_O2 There were no changes in Pa_O2. Because of the absence of clinically important deleterious effects on cardiac pump function, nalbuphine merits further investigation as an analgesic in acute myocardial infarction.