Journal of Sleep Sciences 2017. 0(0):.

Lung Function Capacities in Obstructive Sleep Apnea Syndrome
Abolhasan Halvani, Shahrzad Sabzevari, Mehrdad Mostaghaci, Amir Houshang Mehrparvar, Mohammad Javad Zare Sakhvidi, Raziyeh Soltani Gerdfaramarzi


Background and Objective: Previous studies have reported abnormal changes in spirometric parameters and flow-volume curves in patients with Obstructive Sleep Apnea Syndrome (OSAS) during sleep. This study aimed to evaluate the lung function capacities and flow-volume curves in these patients.

Materials and Methods: This was a cross-sectional study. A total of 120 adults aged 18 to 65 years with suspected OSAS were selected. A full record of demographic characteristics and history of chronic diseases, as well as the results of spirometry and polysomnography were obtained. Spirometric indices and flow-volume curves in OSAS patients and normal subjects were compared, and the association between these indices and the severity of Apnea–Hypopnea Index (AHI) were evaluated.

Results: The mean Body Mass Index (BMI) was 30.85 ± 6.18 kg/m2 . Average neck and abdominal circumferences were 41.68 ± 3.53 and 108.56 ± 14.34 (cm); respectively. The subjects were divided into three groups based on their AHI. The sawtooth signal was observed in flowvolume curve in 20.2% and 2.8% of patients with and without OSAS; respectively. Significant differences were seen in sawtooth appearance signs and FEF50 / FIF50 (P-value>0.001), but these parameters were not significantly different in AHI subgroups of sleep apnea.

Conclusion: Sawtooth sign and FEF50/FIF50 ≥1 could be useful in diagnosis of OSAS, although it cannot be used to predict the severity. Despite a significant difference in sawtooth sign and FEF50/FIF50 between OSAS patients and normal subjects, no significant differences in lung functions was observed between OSAS patients and normal subjects.


Spirometry; Obstructive Sleep Apnea Syndrome (OSAS); Sawtooth sign

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