A documented episode of pulmonary vasoconstriction in systemic sclerosis.

Severe paroxysmal pulmonary hypertension with increased pulmonary vascular resistance precipitated by exposure to cold is postulated as the mechanism causing dyspnea and cardiopulmonary arrest in a patient with systemic sclerosis. Multiple exposures to cold air and a 0 degree C saline infusion resulted in the acute onset of dyspnea and peripheral vasoconstriction. Pressure readings from a Swann-Ganz catheter in place during the saline-induced dyspneic attack showed significant elevation of pulmonary arterial pressure and vascular resistance, suggesting that pulmonary vasospasm caused the attack.