Esmolol or Sodium Nitroprusside for Induced Hypotension During Isoflurane Anesthesia

Abstract

This study examines the effects of esmolol (E) and sodium nitroprusside (SNP) in inducing hypotension during isoflurane (I) anesthesia. Nineteen men (E = 10, SNP = 9) undergoing genitourinary surgery were studied. Cardiovascular, endocrine (catecholamine levels and plasma renin activity [PRA]), and arterial blood gas data were collected before, during, and after hypotension employing infusions of SNP at 0.5, 1.0, or 2.0 μg/kg/min or E at 75, 150, or 300 μg/kg/min. The hypotensive agent and its dosage sequence were chosen randomly Compared with preinduction values, there was no difference in the PRA or the heart rate during hypotension in the E group, but in the SNP group, both increased significantly Furthermore, the authors also observed a linear, dose-dependent reduction in I requirement with increasing doses of SNP, whereas with E, the I requirement decreased only with the higher dose. Arterial oxygenation also worsened with SNP as compared with E during hypotension. The authors conclude that during I anesthesia, E appears to be a better agent than SNP for induced hypotension.