Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Hypoxic pulmonary vasoconstriction (HPV) is a fundamental physiological process whereby ventilation/perfusion matching is optimized through the constriction of the pulmonary circulation supplying poorly ventilated lung units. In their 1981 paper in the Journal, Noble, Kay, and Fisher used a series of animal experiments to show that alveolar carbon dioxide (CO2) plays a critical role in the regulation of hypoxic pulmonary vasoconstriction. At physiological concentrations, CO2 potentiates the HPV response, and the absence of alveolar CO2 blunts HPV. The enhancement of HPV by CO2 resulted in reduced perfusion of specific hypoxic lung regions, thereby improving systemic oxygenation in lung-ventilated dogs.