<p>Differences Between Central Airway Obstruction and Chronic Obstructive Pulmonary Disease Detected with the Forced Oscillation Technique</p>

Abstract

Background: Obstructive ventilatory disturbances occur in both chronic obstructive pulmonary disease (COPD), a typical disease representative of peripheral airway obstruction, and central airway obstruction (CAO). Pulmonary function tests (PFTs), which depend on patient effort, are traditionally used to evaluate lung function. The forced oscillation technique (FOT) is an effort-independent method for examining lung function during tidal breathing. The FOT is used universally to assess respiratory function in patients with COPD. Several studies have measured FOT to assess ventilatory disturbances in CAO. The results showed that FOT measurements in patients with CAO were similar to those reported in patients with COPD. However, no studies have compared FOT measurements directly between CAO and COPD. The aim of this study was to identify differences in ventilatory disturbances between peripheral and central airway obstructions in COPD and CAO, before patients received pharmacological therapy or bronchoscopic interventions, respectively. Patients and Methods: We retrospectively included 16 patients with CAO (10 cases of tracheal obstruction and 6 cases of bronchial obstruction) and 75 treatment-naïve patients with COPD (60 cases in Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage II and 15 cases in GOLD stage III) that were admitted from December 2013 to May 2017. Prior to treatment, patients were examined with the FOT and PFTs. Results: All parameters measured with the FOT in the inspiratory phase were significantly worse in patients with CAO than in patients with COPD. The PFTs showed that the CAO group had a significantly lower peak expiratory flow rate. In the airway wall thickening phenotype of COPD, a difference between the inspiratory and expiratory phases of the resonance frequency (ΔFres) was the best indicator for distinguishing between peripheral and central airway obstructions. Conclusion:This study compared differences between CAO and COPD (mainly GOLD stage II). We found that the FOT measurement, ΔFres, was the optimal indicator of the difference between the airway wall thickening COPD phenotype and CAO. Thus, the difference might be due to mechanical changes that occur in COPD with airway wall thickening.

Lung disease burden assessment by oscillometry in a systematically disadvantaged urban population experiencing homelessness or at-risk for homelessness in Ottawa, Canada from a prospective observational study

“…Like the 6-min walk test, oscillometry appears to be an indicator of respiratory diseases, but it is unknown if it can differentiate between specific disease entities such as small airway diseases (i.e., OLDs like COPD and asthma), central airway diseases or neuromuscular diseases affecting lung function. Nonetheless, we do know that oscillometry is associated with symptom burden, making it a useful effort-independent test in the assessment and monitoring of multiple lung diseases [20,21,46].…”

“…Oscillometry has been found to correlate with patient self-reported symptoms of chronic obstructive pulmonary disease (COPD) and asthma [9,14,15] and to be as sensitive as spirometry in assessing lung disease in epidemiological studies [16][17][18][19]. Despite its ability to detect small airway disease and disease burden, it is unclear whether oscillometry can distinguish between asthma and COPD diagnoses [20][21][22]. Oscillometry resistance and reactance values at low frequency have been shown to correlate strongly with transpulmonary resistance measured by esophageal manometry and other traditional small airway measures [23].…”

Computational Fluid Dynamics Modeling in Respiratory Airways Obstruction: &lt;i&gt;Current Applications and Prospects&lt;/i&gt;

“…The application of CFD was first grounded in aerospace and mechanical areas but recently, CFD has gained grounds in other areas such as biomedical science and engineering. Probably, the application of CFD in medical field has lagged behind because of the complex nature of human anatomy and dynamic behavior of body fluids [105]. In the area of biomedical engineering, there are merits when considering CFD over traditional ways of investigating airway dynamics in the respiratory system.…”

Challenges in diagnosis and management of central airway obstruction: Case series

“… 5 Misdiagnosis of CAO as asthma/chronic obstructive pulmonary disease (COPD) results in challenges in clinical practice. 6 , 7 Moreover, the proper management strategy requires personalized therapy ranging from conservation to medical or surgical interventions. 8 Herein, we described five CAO cases, two with non-malignant etiology misdiagnosed as asthma, one with malignant etiology masquerading as COPD exacerbation, one with malignant etiology misdiagnosed as non-resolving pneumonia, and one with malignant etiology misdiagnosed as COPD.…”