Plethysmographic data and profile of North-African patients with severe obstructive sleep apnea treated with continuous positive airway pressure

Abstract

ABSTRACT Objectives In obstructive sleep apnea (OSA) patients, the frequencies of the different ventilatory defects are unknown and the studies examining their plethysmographic profiles and/or pulmonary function test data have contradictory results. The main aim of this prospective study was to establish the plethysmographic profile of severe OSA patients treated with continuous positive airway pressure (CPAP). Methods 100 (33 females) clinically consecutive stable patients with severe OSA treated with CPAP were included. Anthropometric, polysomnographic, and pulmonary function test data were collected. The following definitions were applied: large airways obstructive ventilatory defect (LAOVD): (FEV1/SVC or FEV1/FVC < lower limit of normal (LLN), small airways obstructive ventilatory defect (SAOVD): (FEV1/FVC and FVC) > LLN and maximal mid-expiratory flow (MMEF) < LLN, restrictive ventilatory defect (RVD): total lung capacity (TLC) < LLN, lung-hyperinflation: residual volume > upper limit of-normal, and nonspecific ventilatory defect (NSVD): (FVC and FEV1) < LLN and TLC > LLN and (FEV1/SVC or FEV1/FVC) > LLN. Results The plethysmographic profile of OSA patients included RVD (73%), SAOVD (50%), LAOVD (16%), mixed-VD (11%), lung-hyperinflation (11%), and NSVD (2%). Conclusion The plethysmographic profile of OSA patients was dominated by the presence of an RVD.