Use of capnography for prediction of obstruction severity in non-intubated COPD and asthma patients

Barak Pertzov,Moshe Heching,Yael Shostak,Dorit Shitenberg,Mordechai R Kramer,Dror Rosengarten,Michal Ronen

doi:10.1186/s12931-021-01747-3

Barak Pertzov, Moshe Heching + Show 5 more

Open Access

https://doi.org/10.1186/s12931-021-01747-3

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Abstract

BackgroundCapnography waveform contains essential information regarding physiological characteristics of the airway and thus indicative of the level of airway obstruction. Our aim was to develop a capnography-based, point-of-care tool that can estimate the level of obstruction in patients with asthma and COPD.MethodsTwo prospective observational studies conducted between September 2016 and May 2018 at Rabin Medical Center, Israel, included healthy, asthma and COPD patient groups. Each patient underwent spirometry test and continuous capnography, as part of, either methacholine challenge test for asthma diagnosis or bronchodilator reversibility test for asthma and COPD routine evaluation. Continuous capnography signal, divided into single breaths waveforms, were analyzed to identify waveform features, to create a predictive model for FEV1 using an artificial neural network. The gold standard for comparison was FEV1 measured with spirometry.Measurements and main resultsOverall 160 patients analyzed. Model prediction included 32/88 waveform features and three demographic features (age, gender and height). The model showed excellent correlation with FEV1 (R = 0.84), R2 achieved was 0.7 with mean square error of 0.13.ConclusionIn this study we have developed a model to evaluate FEV1 in asthma and COPD patients. Using this model, as a point-of-care tool, we can evaluate the airway obstruction level without reliance on patient cooperation. Moreover, continuous FEV1 monitoring can identify disease fluctuations, response to treatment and guide therapy.Trial registrationclinical trials.gov, NCT02805114. Registered 17 June 2016, https://clinicaltrials.gov/ct2/show/NCT02805114

Highlights

Lung function measurement with a spirometer is considered the gold standard for assessment of asthma and chronic obstructive pulmonary disease (COPD) [1, 2]
In this study we have developed a model to evaluate Forced Expiratory Volume in 1 s (FEV1) in asthma and COPD patients
Spirometry can be used to diagnose airway hyperresponsiveness (AHR); the methacholine challenge test (MCT) evaluates AHR by measuring FEV1 before and Pertzov et al Respir Res (2021) 22:154 after the introduction of an increasing concentration of methacholine, an airway provoking agent, which in cases of AHR will cause a decrease in FEV1 of more than 20% [5]

Summary

Introduction

Lung function measurement with a spirometer is considered the gold standard for assessment of asthma and chronic obstructive pulmonary disease (COPD) [1, 2]. Capnography is a waveform display of CO2 concentration in a gas mixture It is often measured in intubated patients to confirm tracheal tube position and to evaluate patient ventilation [6,7,8]. Phase II (points B to C) reflects the arrival of gas from the respiratory bronchioles and alveoli. While capnography is currently used to monitor respiration rate and EtCO2, the CO2 waveform contains essential information regarding physiological characteristics of the respiratory system. The aim of this study was to develop a capnography-based prediction model, to be used as a point-of-care tool that can evaluate the airway obstruction level in asthma and COPD patients. Our aim was to develop a capnography-based, point-ofcare tool that can estimate the level of obstruction in patients with asthma and COPD

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