Hypoxemia with atelectasis during clazosentan therapy after subarachnoid hemorrhage: a potential effect of suppressed hypoxic pulmonary vasoconstriction.

Endothelin-1 contributes to hypoxic pulmonary vasoconstriction (hypoxic pulmonary vasoconstriction), which preserves ventilation-perfusion (V/Q) matching by diverting blood flow from poorly ventilated regions; pharmacologic ET-A blockade may attenuate hypoxic pulmonary vasoconstriction, increasing intrapulmonary shunt and impairing oxygenation.

We report a man in his 60s with aneurysmal subarachnoid hemorrhage (World Federation of Neurosurgical Societies [WFNS] I, Fisher 3) who underwent clipping surgery and postoperative clazosentan infusion (10 mg/h, standard Japanese dosage).