Characters of pulmonary function testing in pulmonary alveolar proteinosis: analysis of 27 patients

Abstract

Objective Pulmonary alveolar proteinoais (PAP) is a rare respiratory disorder featured with lipoproteinaceous material accumulating within alveoli. Few studies on the characters of pulmonary function testing in PAP have been addressed. The purpose of this study was to investigate the clinical features of lung function testing in the diagnosis and therapy of PAP. Methods Twenty-seven patients with PAP (15 to 54 years) were enrolled in the institute and histopathologically diagnosis was proven by antiperiodic acid Schiff positive reaction. Spirometry and diffusion capacity were measured in all patients, among them 12 were tested with total lung volume. Ten patients with PAP were treated with bronchoalveolar lavage (BAL). Results of pulmonary function tests were compared before and after the treatment. Results Baseline percentage of prediction in FVC, FEV1, FEV1/FVC, PEF, DLCO and DLCO/VA were (79.67±16.21 ) %, (83.94±16.07)%,(89.20±5.50)%, (107. 64±17.73)%, (49.27±21.83)%, (69.92±20.11)%, respectively. Baseline percentage of prediction in TLC, RV, RV/TLC and FRC were (80. 60±19.56) %,(86.03±38. 10)%, (32. 73±9.48)% and (84.91±28.08 ) %, respectively. The incidence of impaired pulmonary function in 27 patients was 55.6% in FVC and 44.4% in FEV1 and 0% in FEV1/FVC and 3. 7% in PEF and 88. 9% in DLCO and 70.4% in DLCO/VA. For the abnormal lung volumes in 12 patients,the decreased TLC was found in 6 patients, decreased RV in 5 patients,increased RV in 2 patients and increased RV/TLC in 6 patients,decreased FRC in 4 patients. FVC, FEV,1 ,DLCO and DLCO/VA were improved after whole lung lavage by 5.47%, 5.50%, 31.07% and 20. 35%, respectively. Significant improvements were found in DLCO and DLCO/VA after treatment (t=-3.551,-3. 159, P=0.006 and 0. 012). Conclusions The impairment of pulmonary function in PAP is featured by restrictive ventilation disorder and reduction of diffusion capacity, with more severe of the latter. After being treated with BAL, the pulmonary function of PAP could be markedly improved. Key words: Pulmonary alveolar proteinosis; Pulmonary function testing; Bronchoalveolar lavage