Comparative assessment of small airway dysfunction by impulse oscillometry and spirometry in chronic obstructive pulmonary disease and asthma with and without fixed airflow obstruction

Abstract

BackgroundSmall airways play a major role in the pathogenesis and prognosis of chronic obstructive pulmonary disease (COPD) and asthma. More data on small airway dysfunction (SAD) using spirometry and impulse oscillometry (IOS) in these populations are required. The objective of this study was to compare the two methods, spirometry and IOS, for SAD detection and its prevalence defined by spirometry and IOS in subjects with COPD and asthma with and without fixed airflow obstruction (FAO).DesignThis is a cross-sectional study.MethodsSpirometric and IOS parameters were compared across four groups (COPD, asthma with FAO, asthma without FAO, and healthy subjects). SAD defined by spirometry and IOS criteria were compared.ResultsA total of 262 subjects (67 COPD, 55 asthma with FAO, 101 asthma without FAO, and 39 healthy controls) were included. The prevalence of SAD defined by using IOS and spirometry criteria was significantly higher in patients with COPD (62.7 and 95.5%), asthma with FAO (63.6 and 98.2%), and asthma without FAO (38.6 and 19.8%) in comparison with healthy control (7.7 and 2.6%). IOS is more sensitive than spirometry in the detection of SAD in asthma without FAO (38.6% vs. 19.8%, p = 0.003) However, in subjects with FAO (COPD and asthma with FAO), spirometry is more sensitive than IOS to detect SAD (95.5% vs. 62.7%, p < 0.001 and 98.2% vs. 63.6%, p < 0.001, respectively).ConclusionSmall airway dysfunction was significantly detected in COPD and asthma with and without FAO. Although IOS shows more sensitivity than spirometry in the detection of SAD in asthma without FAO, spirometry is more sensitive than IOS in patients with FAO including COPD and asthma with FAO.

Long COVID symptoms after 8-month recovery: persistent static lung hyperinflation associated with small airway dysfunction

“…In patients with chronic obstructive pulmonary disease, reactance, Fres, and AX were better than resistance parameters in stratifying degree of air trapping and were significantly correlated with RV/TLC [ 24 , 25 ]. IOS is more sensitive than spirometry in detecting SAD in asthma patients without fixed airway obstruction [ 26 ]. Additionally, IOS demonstrates greater sensitivity in detecting SAD compared to FEF25%-75% in symptomatic patients with preserved pulmonary function [ 21 ].…”

Asthma Inflammatory Phenotypes: How Can We Distinguish Them?

“…There is no recommendation of which spirometry parameter is the best predictor of SAD [49]. The study that compared these two methods found that for normal lung function IOS may be more sensitive, while spirometry is a more sensitive method for detecting SAD in abnormal lung function [50].…”

The role of oscillometry in asthma

“…In an observational study of asthmatics with normal spirometry, peripheral airways dysfunction was detected by oscillometry in 54.1% of patients while spirometry-defined peripheral airways dysfunction was detected in only 10% of patients [30 ▪ ]. Another study showed oscillometry was more sensitive than spirometry in detecting peripheral airways dysfunction in asthma patients without fixed airway obstruction, while spirometry was superior in detecting peripheral airways dysfunction in patients with fixed airway obstruction [31]. The high prevalence of peripheral airways dysfunction in asthma, especially when spirometry is normal, makes this variable an especially attractive clinical tool.…”