Intravenous nitroglycerin (NTG) and sodium nitroprusside (SNP) were compared as hypotensive agents in anesthetized children and adolescents. The drugs were studied in a prospective, randomized, double-blind fashion in 14 patients anesthetized with nitrous oxide: oxygen, morphine, and thiopental. NTG in doses as high as 40 μg·kg-1·min-1 was ineffective at decreasing mean arterial pressure (MAP) below 55 mmHg or causing a decrease in MAP greater than one-third of baseline values. SNP was uniformly successful at inducing hypotension in all patients, including those patients in whom NTG failed. The dose of SNP required to induce hypotension was 6-8 μg·kg-1·min-1. Both NTG and SNP decreased systemic vascular resistance, although SNP did so to a much greater degree than NTG (64% vs. 29%; P < 0.01). Only SNP increased cardiac index significantly (2.27 ± 0.35 to 4.44 ± 1.36; P < 0.003). Both drugs reflexly increased heart rate, necessitating the use of intravenous propranolol (range from 1 to 3 mg) in all patients. Both drugs produced small decreases in arterial oxygen tension and increases in the average alveolar-arterial oxygen tension gradient (SNP, 44 ± 13 vs. NTG, 41 ± 6). SNP use was associated with a slight metabolic acidosis (pH = 7.38 ± 0.01; base excess [BE] = -6 ± 1). Neither drug produced any other untoward reaction. SNP appears to be the agent of choice for the reliable and sustained induction of deliberate hypotension in children and adolescents.
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine