Hemodynamic responses to noxious stimuli in brain-dead organ donors

The case report presents evidence for the spinal origin of the marked hypertensive responses to noxious stimuli that may occur in organ donors who fulfill the commonly accepted criteria of brain death. Cardiovascular spinal reflex activity does not invalidate these criteria. For the first time, the catecholamine plasma concentrations have been determined during spinal pressor reflex activity. Circulating epinephrine increased more markedly than norepinephrine in both cases, rising to 4.7 and 44 times the baseline concentration respectively. The relation between plasma norepinephrine and epinephrine suggests involvement of the adrenal medulla in the reflex arc. The literature on spinal hemodynamic reflexes is reviewed.