Cardiovascular responses to ischemia, hypoxia, and hypercapnia of the central nervous system

Abstract

The hemodynamic responses to CNS ischemia and to perfusing the CNS with hypoxic or hypercapnic blood were observed in the dog. A dual, rotating disc oxygenator system was employed to separately perfuse the brachiocephalic artery distribution following confirmed bilateral carotid sinus area denervation. Cerebral ischemia produced a marked increase of blood pressure, peripheral vascular resistance, heart rate, and atrial and ventricular contractility. These same responses were also produced by lowering the pO2 or raising the pCO2 of the CNS perfusate, but were somewhat less marked. The hemodynamic findings resulting from these interventions are similar to those observed during systemic hypoxia. It is, therefore, suggested that the gas composition of the blood perfusing the central nervous system may importantly influence the response of the organism to systemic hypoxia.