Phonocardiography as a monitor of cardiac performance during anesthesia

The usefulness of phonocardiography as a monitor of cardiac performance during anesthesia was investigated in six dogs. Anesthetic depression by halothane, isoflurane and nitrous oxide was demonstrated by the phonocardiogram. Likewise, the stimulating effect of dopamine clearly showed in the recordings. Changes in the amplitude of the first heart sound were found to correlate closely with changes in the maximum rate of rise of left ventricular pressure (r = 0.9551, 0.001). P less than 0.001). Simultaneous changes in cardiac output and arterial pressure also occurred. Cardiac depression from anesthetics and/or disease is a major concern during anesthesia. Perioperative phonocardiography, a simple and noninvasive procedure, merits further investigation as a possible monitor of cardiac performance.