Hemodynamic effects of narcotics.

Salt Lake City, Utah In intact animals and nonaddicted supine patients, morphine and fentanyl and some new, as yet unreleased narcotics, e.g., sulfentanil, produce minimal changes in cardiovascular dynamics." Indeed, Lowenstein et al observed that the introduction of large (anesthetic) doses of morphine (as much as 1 mg/kg) intravenously as the sole or principal anesthetic did not cause significant circulatory changes in patients without cardiac disease. In patients with aortic valvular disease, stroke volume and cardiac output increased. Yet several investigators observed depression of myocardial contractility by narcotics when isolated myocardial muscle and heart-lung preparations were perfused with saline solution. When blood was substituted as the perfusing solution, no depressant effect was observed with as much as 30 mg/kg morphine in dog and cat heartlung preparations. Apparently, fentanyl also does not change myocardial mechanics in blood-perfused preparations, whereas meperidine does cause considerable myocardial depression. Myocardial depression does not occur after morphine administration in intact animals or man. Schmidt and Livingston found no evidence of cardiac depression in awake dogs given as much as 100 mg/kg morphine. Vasco et al found that morphine had a positive inotropic effect in dogs, which