Role of hypoxic pulmonary vasoconstriction in pulmonary gas exchange and blood flow distribution

Abstract
The regulation of the distribution of ventilation/perfusion ratios by hypoxic pulmonary vasoconstriction contributes to both the efficiency of gas exchange and to pulmonary hemodynamics. In this review, the first of a two part series, are summarized the physiologic principles on which the analysis of ventilation/perfusion ratios and of pressure — flow relationships are based. A new combined analysis is introduced that permits the important contributions of hypoxic pulmonary vasoconstriction to overall gas exchange to be demonstrated in the circumstances of clinical complexity.