title: Sodium nitroprusside: hemodynamic dose-response during enflurane and morphine anesthesia.
abstract: To date there has been no description of the hemodynamic dose-response relationship between enflurane and sodium nitroprusside (SNP), although these drugs are often used together to induce deliberate hypotension. Utilizing aortic root cannulation and thermistor-tipped pulmonary artery catheters, this relationship was studied in six beagles during 1 and 2% enflurane anesthesia and compared with the hemodynamic response induced by SNP in the awake state and during anesthesia with intravenous morphine (6 mg/kg). Each animal received a standard infusion of 100 microgram/kg of SNP administered at three different flow rates (5, 10, and 20 microgram/kg/min). SNP infusion resulted in dose-related reductions in mean arterial pressure, systemic vascular resistance and left ventricular stroke work, whereas cardiac output increased. Enflurane potentiated the hypotensive effects of SNP in a dose-related fashion. During morphine anesthesia, however, the hemodynamic effects of SNP were virtually indistinguishable from those observed in the awake state.
mesh_terms: D000769:Anesthesia, Inhalation; D000771:Anesthesia, Intravenous; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004737:Enflurane / Q000494:pharmacology*; D005292:Ferricyanides / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008738:Methyl Ethers / Q000494:pharmacology*; D009020:Morphine / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D005292:Ferricyanides; D008738:Methyl Ethers; D009599:Nitroprusside; D009020:Morphine; D004737:Enflurane