Related Experiment Video
Updated: Apr 17, 2026

Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Characteristics of small airway disease in patients with HIV infection: insights from spirometry and impulse
Ilgim Vardaloglu1, Buket Caliskaner Ozturk1, Hazal Cansu Culpan2
1Department of Chest Diseases, Istanbul University-Cerrahpasa Cerrahpasa Faculty of Medicine, Istanbul, Turkey.
Background:
Airway diseases that are independent of smoking behaviour are frequent in people living with HIV (PLWH). Spirometry, the gold standard for diagnosing airway diseases, may not detect small airway disease (SAD) when forced expiratory volume in 1 s/forced vital capacity is normal. However, impulse oscillometry (IOS) can detect SAD even when the spirometry is normal. This study aims to evaluate characteristics of SAD in PLWH by using IOS and exploring the diagnostic performance of IOS measurements to detect SAD.
Methods:
This cross-sectional study included 127 PLWH on antiretroviral therapy without known airway disease. IOS was done first, followed by spirometry. Patients whose maximal mid-expiratory flow (MMEF) value was below 65% were defined as having spirometric SAD. Clinical characteristics and IOS measures were compared between those who had and those who did not have SAD. A receiver operating characteristic analysis was done to determine the diagnostic performance of IOS measures to diagnose spirometric SAD.
Results:
Mean age was 43.5±12.5 years and 60 patients were non-smokers. Spirometric SAD was observed in 34% of all patients. R5, R5-R20, AX and Fres were significantly higher in the patients who had spirometric SAD. Smoking history, duration of antiretroviral therapy and history of pneumonia were significantly associated with SAD. The optimal cut-off value for R5-R20 was 0.08 for SAD (sensitivity of 71.8% and specificity of 58.1%) and the optimal cut-off value for AX was 0.55 (sensitivity of 51.2% specificity of 91.7%).
Conclusion:
SAD is common in PLWH and IOS may serve as a supportive tool for the clinical assessment of small airway involvement.
Related Concept Videos
Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
COPD: Pathogenesis and Clinical Features
The primary cause for the onset of COPD is cigarette smoking and exposure to air pollution. These hazardous factors initiate a chain reaction within the lungs, resulting in chronic inflammation, damage to the airways, and a...
Pulmonary Function Tests
Pulmonary Function Tests are crucial diagnostic tools for assessing respiratory function, particularly in patients with chronic respiratory disorders. They comprehensively evaluate lung volumes, ventilatory function, breathing mechanics, diffusion, and gas exchange. These tests help diagnose pulmonary diseases and play a significant role in monitoring disease progression, evaluating disability, and assessing response to therapy.
PFTs involve using a spirometer, a...
Chronic Obstructive Pulmonary Disease-II: Pathophysiology
Chronic Inflammation
Chronic Obstructive Pulmonary Disease-I: Introduction
Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...

