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

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.

KEYWORDS:

• Obstructive sleep apnea
• obesity
• lung function testing
• plethysmography

Authors’ contributions

M. Martani and M.K. Bourahli conceived the study, participated in its design, performed the statistical analysis, and helped to draft the manuscript. M. Boudriga conceived the study, participated in its design, and helped to draft the manuscript. H. Ben Saad conceived the study, participated in its design, performed the statistical analysis, helped to draft the manuscript, and coordinate the paper management. All authors read and approved the final manuscript.

Article highlights

• In patients with OSA, the frequencies of the different ventilatory defects are variable.

• Studies aiming at evaluating the pulmonary function test data of OSA patients reported contradictory results.

• 100 Algerian patients with severe OSA treated with continuous positive airway pressure performed a plethysmography.

• Their plethysmographic profile was characterized by the presence of restrictive ventilatory defect (73%), small airways obstructive ventilatory defects (50%), trapping phenomenon (18%), large airways obstructive ventilatory defects (16%), and lung-hyperinflation (11%).

• Compared with healthy non-obese and obese subjects, the obese OSA subgroup aged ≥ 40 years had significantly lower pulmonary function test data.

Acknowledgments

Authors wish to thank Professor Samir Boukattaya for his invaluable contribution to the improvement of the quality of the writing in the present article.

Declaration of interest

H Ben Saad reports personal fees from AstraZeneca, Saiph, Teriak, Opalia Recordati and Chiesi. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This paper was not funded.