Importance of hypoxic pulmonary vasoconstriction with atelectasis

This survey summarizes information on various factors that determine responses to hypoxic pulmonary vasoconstriction. The emphasis is on the clinical relevance of these responses for atelectasis. Flow diversion reduces the functional effect of lung collapse by redistributing the pulmonary blood flow so as to promote restoration of arterial oxygen tension. The factors shown to influence the outcome include size of the atelectactic segment, mixed venous oxygen tension, intrapleural and intraalveolar pressure (transpulmonary pressure), cardiac output, and pulmonary transmural vascular pressure.