Study objectives: To investigate the long-term outcome of lung function in survivors of severe ARDS after modern treatment strategies including lung protective mechanical ventilation and prone positioning maneuvers.
Design: Follow-up cohort study.
Setting: University hospital pulmonary division and level 1 trauma center.
Patients: Sixteen survivors of severe ARDS (from 1992 to 1994) with a lung injury score ≥ 2.5.
Measurements: The follow-up study (from 1995 to 1996) included interview, physical examination, chest radiographs, static and dynamic lung volumes, diffusion capacity of the lung for carbon monoxide (Dlco), blood gas analysis, and cardiopulmonary exercise testing (CPET).
Results: The mean ± SD interval between hospital discharge and functional assessment was 29.5 ± 8.7 months (range, 15.0 to 40.7 months). In approximately one half of the patients, mild abnormalities in static and dynamic lung volumes were found. In 25% (4 of 16 patients), lung function was obstructive; in 25% (4 of 16 patients), lung function was restrictive; and in 6.3% (1 of 16 patients), a combined obstructive-restrictive pattern was revealed. Dlco was impaired in 12.5% (2 of 16 patients); gas exchange during exercise was impaired in 45.5% (5 of 11 patients).
Conclusions: Residual obstructive and restrictive defects as well as impaired pulmonary gas exchange remain common after severe ARDS. CPET is a very sensitive measure to evaluate residual impairment of lung function after ARDS. Using CPET, reduced pulmonary gas exchange can be detected in many patients with normal Dlco.