Effects of prenalterol on central hemodynamics and myocardial metabolism in experimental propoxyphene-induced shock.
The hemodynamic and cardiometabolic effects of prenalterol were evaluated in propoxyphene-induced circulatory shock in 10 pentobarbital-anesthetized pigs. Circulatory shock (i.e. a systolic arterial blood pressure below 60 mmHg (8 kPa) and/or a cardiac index of less than 2.0 1 X min-1 X m-2) was induced by intravenous propoxyphene chloride 15 mg X min-1. Circulatory shock occurred after 26 +/- 3 mg X kg-1 of propoxyphene. During continuous infusion of propoxyphene, consecutive doses of prenalterol 0.5, 1.0, 2.0 and 4.0 mg i.v. were injected with an interval between increments of 8 min. The maximum effect of prenalterol was seen following the 2 mg dose. Increases were observed in mean arterial blood pressure, cardiac index, stroke volume index, left ventricular stroke work index, right ventricular stroke work index, maximum rate of rise of ventricular pressure, and total body oxygen consumption. Decreases were observed in pulmonary artery occlusion pressure, mean right atrial pressure and systemic vascular resistance, whereas heart rate and pulmonary vascular resistance remained unchanged. The cardiometabolic parameters: coronary sinus flow, coronary vascular resistance, myocardial oxygen consumption and extraction, remained low. Due to profound vasodilation, normal perfusion pressures were not reestablished. In conclusion, prenalterol improved cardiac performance by a significant positive inotropic action. However, pure inotropic stimulation was not sufficient to counteract the circulatory shock state during severe propoxyphene intoxication.
D000818:Animals; D011431:Dextropropoxyphene / Q000037:antagonists & inhibitors*; D006439:Hemodynamics / Q000187:drug effects*; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D011294:Prenalterol / Q000494:pharmacology / Q000627:therapeutic use*; D012769:Shock / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D013552:Swine
D011294:Prenalterol; D011431:Dextropropoxyphene