Investigation of the potential predictive value of flow-volume curve changes in patients with obstructive sleep apnea syndrome

Year 2025, Volume: 11 Issue: 6, 1157 - 1166

Fatma Arzu Akkuş , Şebnem Yosunkaya

https://doi.org/10.18621/eurj.1777758

Abstract

Objectives: The relationship between pulmonary function tests (PFT) performed while awake and sleep-related breathing disorders is not yet well defined. This study aimed to examine the potential of flow-volume curve abnormalities in assessing both the presence and severity of obstructive sleep apnea syndrome.

Methods: This retrospective study reviewed medical records of patients evaluated for suspected obstructive sleep apnea syndrome (OSAS) between May 2011 and April 2013. Among 141 patients with available PFT, 99 were diagnosed with OSAS, and 42 were normal based on polysomnography results. Patients were classified into OSAS and control groups, and pulmonary function parameters, including flow-volume curve features, were analyzed.

Results: Of the OSAS patients, 80 (80.8%) were male, while 22 (52.4%) males were present in the control group, which consisted of patients not diagnosed with obstructive sleep apnea syndrome. Among pulmonary function test parameters, the ratio of maximal mid-expiratory flow to forced vital capacity (FEF25-75/FVC) was lower in the obstructive sleep apnea syndrome group than in the control group (P<0.05). Patients with the sawtooth sign showed significantly higher apnea-hypopnea index, apnea-hypopnea index during rapid eye movement sleep, and total apnea scores (P<0.05). The presence of sawtooth signs in the flow-volume loop was useful for identifying more severe cases of obstructive sleep apnea syndrome.

Conclusions: The complex pathophysiology of obstructive sleep apnea syndrome complicates the identification of patients who need polysomnography. Flow-volume curve abnormalities, indicating airway instability in the upper respiratory tract, are common in these patients and may serve as early indicators of obstructive sleep apnea syndrome.

Keywords

Obstructive sleep apnea , sleep apnea , polysomnography , pulmonary function test , flow-volume curve , spirometry

Ethical Statement

This study was approved by the Konya University Meram Faculty of Medicine Non-Interventional Clinical Research Ethics Committee (Decision No.: 2018/12-02 and dated 02.02.2012). All procedures performed during data collection, review of patient records, and study implementation complied with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its subsequent amendments. Informed consent was waived because of the retrospective nature of the study and the analysis used anonymous clinical data.

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