Flow-volume curve abnormalities and obstructive sleep apnea syndrome

Area of Science:

• Respiratory Medicine
• Sleep Medicine
• Pulmonology

Background:

• Flow volume curve abnormalities have been proposed as indicators for diagnosing obstructive sleep apnea syndromes.
• These abnormalities may manifest as extrathoracic airway obstruction or upper airway fluttering.

Purpose of the Study:

• To investigate the association between flow volume curve abnormalities and obstructive sleep apnea syndrome (SAS).
• To determine if upper airway abnormalities are specific to obstructive SAS or if they indicate other mechanisms of airway occlusion.

Main Methods:

• Conducted spirometry and flow-volume curve analysis on 57 patients suspected of having sleep apnea syndrome.
• Utilized ENT examination and polysomnography for comprehensive sleep apnea assessment.
• Categorized patients into obstructive SAS, central SAS, and no SAS groups.

Main Results:

• Signs of upper airway fluttering (sawtooth sign) were observed in 61% of obstructive SAS patients and 46% of non-obstructive SAS patients.
• Extrathoracic upper airway obstruction (FEF50/FIF50 > 1) was present in 67% of obstructive SAS patients and 71% of non-obstructive SAS patients.
• Abnormal flow volume curves were prevalent in both obstructive and non-obstructive SAS groups.

Conclusions:

• Upper airway abnormalities detected via flow volume curves are not exclusively linked to obstructive SAS.
• The findings support the hypothesis that a central component may contribute to upper airway occlusion during sleep.
• Flow volume curve analysis may offer insights beyond obstructive mechanisms in sleep-related breathing disorders.