Myocardial hemodynamics during induced hypotension: a comparison between sodium nitroprusside and adenosine triphosphate.

Adenosine triphosphate (ATP) has been reported to be a hypotensive agent similar in effect to sodium nitroprusside (SNP). The purpose of this study was to examine and compare the effects of both SNP and ATP on general coronary hemodynamics, myocardial O2 consumption, and circulating catecholamines. Twelve dogs were anesthetized with 1.

Comparison of cardiovascular responses to verapamil during enflurane, isoflurane, or halothane anesthesia in the dog.

The cardiovascular responses to increasing infusion rates of the slow calcium channel inhibitor, verapamil, were studied in three groups of dogs during either enflurane, isoflurane, or halothane anesthesia. Control hemodynamic values and plasma samples were taken after 2 h of anesthesia with the given agent. Increasing infusion rates of verapamil were given to achieve a range of plasma verapamil levels up to approximately 500 ng X ml-1.

Effects of fentanyl, naloxone, and clonidine on hemodynamics and plasma catecholamine levels in dogs.

A 50-micrograms/kg dose of fentanyl, given intravenously in divided doses to dogs under enflurane-nitrous oxide anesthesia caused sharp decreases in heart rate (HR), arterial blood pressure (AP), left ventricular dP/dt, and plasma levels of catecholamines. Naloxone, 20 micrograms/kg given 65-70 min later, completely and rapidly reversed these changes. Because the cardiovascular effects of fentanyl and naloxone occurred in unparalyzed animals under surgical anesthesia without eliciting any motor responses, it seems unlikely that they can be ascribed to changes in awareness and surgical stimulation, especially pain.