Spirometry and flow-volume curve in patients with obstructive sleep apnea

Area of Science:

• Pulmonary Medicine
• Sleep Medicine
• Diagnostic Tools

Background:

• Obstructive Sleep Apnea (OSA) is a common sleep disorder.
• Spirometry is a standard pulmonary function test.
• The utility of spirometry in diagnosing OSA is not well-established.

Purpose of the Study:

• To determine the prevalence of spirometric abnormalities in patients with OSA.
• To evaluate the clinical usefulness of spirometric findings in diagnosing OSA.

Main Methods:

• An observational study of 138 patients suspected of having OSA was conducted.
• Spirometric indices and flow-volume curves were analyzed.
• Specific signs like the saw-tooth sign and FEF(50)/FIF(50) ratio were assessed.

Main Results:

• The saw-tooth sign was present in 12.3% and FEF(50)/FIF(50) >1 in 26.1% of OSA patients.
• These abnormalities did not correlate with OSA severity (AHI) or other patient characteristics.
• Spirometric abnormalities were not common in OSA patients without known lung disease.

Conclusions:

• Spirometric abnormalities are infrequent in OSA patients without co-existing lung conditions.
• The saw-tooth sign and FEF(50)/FIF(50) >1 are not reliable indicators for predicting OSA.