Sympathetic Nervous System Sensitivity to Hemorrhagic Hypotension in the Subhuman Primate

Publisher Website
Google Scholar
Abstract
The endogenous catecholamine response to hemorrhagic hypotension is poorly defined since most data have been derived from experiments in lower animal species. To clarify this situation the plasma norepinephrine (NE) and epinephrine (E) responses to hemorrhagic hypotension were studied in 10 healthy male baboons (Papia anubis). After an overnight fast, animals were tranquilized with 100 mg of ketamine hydrochloride after which femoral artery and vein catheters were inserted. The animals then underwent phlebotomy of 20 ml/kg over 60 min with retransfusion of the autologous blood over the next 30 min. Plasma specimens for catecholamines were collected at 5, 15, 30 and 60 min during phlebotomy and again at 15 and 30 min during retransfusion. Plasma NE and E concentrations were measured by a radioenzymatic technique. Mean arterial blood pressue (MAP) decreased (P < 0.01) and heart rate (HR) increased (P < 0.01) within 15 min of phlebotomy and these variables returned to baseline with retransfusion. Plasma NE and E levels increased (P < 0.025) within 5 min of the onset of hemorrhage and within 15 min plasma NE concentrations were 56% above baseline, whereas plasma E levels were 6 times greater than baseline. With retransfusion, plasma NE and E levels returned to baseline concentrations. In a primate species, the sympathetic nervous system evidently responds rapidly to hemorrhage; Contrary to prior studies in rats, plasma NE increases as rapidly as E but not to the same degree; plasma NE and E concentrations rapidly return to baseline levels with fluid resuscitation. There thus appears to be little justification for the use of exogenous synthetic catecholamines in hemorrhagic hypotensions where fluid resuscitation remains the treatment of choice.

This publication has 1 reference indexed in Scilit: