REDUCED PULMONARY CAPILLARY BLOOD-VOLUME AS A LONG-TERM SEQUEL OF ARDS

Lung function was evaluated in 9 survivors of ARDS. All patients were asymptomatic at rest at the time of the study, 5.5-19 mo. after extubation (mean 12.5). Six had mild to moderate exertional dyspnea. Chest X-ray films showed no gross parenchymal abnormalities. Spirometry and pulmonary mechanics were either normal or minimally altered, particularly in smokers. At submaximal exercise levels, effort was limited by tachycardia in 8 patients; one subject showed ventilatory and cardiovascular limitations. Spirometry and pulmonary mechanics are restored to normal within 6 mo. after extubation, and gas exchange abnormalities persist after ARDS and might be related to intrapulmonary shunts at rest, whereas during exercise a decreased pulmonary capillary blood volume might be the primary factor.