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The measurement of lung volumes using body plethysmography and helium dilution methods in COPD patients: a correlation and diagnosis analysis

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ABSTRACT

Chronic obstructive pulmonary disease (COPD) is a chronic airway disease characterized by persistent airflow limitation. Moreover, lung hyperinflation evaluated by lung volumes is also the key pathophysiologic process during COPD progression. Nevertheless, there is still no preferred method to evaluate lung volumes. For this study, we recruited 170 patients with stable COPD to assess lung volumes stratified by airflow limitation severity. Lung volumes including residual volume (RV) and total lung capacity (TLC) were determined by both body plethysmography and helium dilution methods. The discrepancies between these two methods were recorded as ΔRV%pred, ΔTLC%pred, and ΔRV/TLC. We found that ΔRV%pred, ΔTLC%pred, and ΔRV/TLC increased significantly with the severity of COPD. The differences of lung capacity between these two methods were negatively correlated with FEV1%pred, and diffusing capacity for carbon monoxide (DLCO%pred). Moreover, the receiver operating characteristic (ROC) for ΔTLC%pred to distinguish severe COPD from non-severe COPD had an area under curve (AUC) of 0.886. The differences of lung volume parameters measured by body plethysmography and helium dilution methods were associated with airflow limitation and can effectively differentiate COPD severity, which may be a supportive method to assess the lung function of stable COPD patients.

No MeSH data available.


Average TLC%pred (A), RV%pred (B), and RV/TLC (C) as measured by whole-body plethysmography and multi-breath helium dilution, varying by severity. The results are plotted as means ± SD; Differences between body plethysmography and helium dilution methods were analyzed with paired T-test. †p < 0.001, ‡p < 0.05. he, helium dilution; pleth, plethysmography; TLC, total lung capacity; RV, residue volume.
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f1: Average TLC%pred (A), RV%pred (B), and RV/TLC (C) as measured by whole-body plethysmography and multi-breath helium dilution, varying by severity. The results are plotted as means ± SD; Differences between body plethysmography and helium dilution methods were analyzed with paired T-test. †p < 0.001, ‡p < 0.05. he, helium dilution; pleth, plethysmography; TLC, total lung capacity; RV, residue volume.

Mentions: A total of 170 patients were included into this prospective study. All patients were confirmed with stable COPD according to GOLD standards1. None of the patients had an acute exacerbation during previous 4 weeks before pulmonary function tests, and all medications which may alter lung function were stopped for at least 72 hours. Pulmonary function variables are performed in Table 1 and Fig. 1. The subject population included 44 patients (25.9%) with GOLD Classification 1, 54 patients (31.8%) with GOLD Classification 2, 34 patients (20.0%) with GOLD Classification 3, and 38 patients (22.3%) with GOLD Classification 4.


The measurement of lung volumes using body plethysmography and helium dilution methods in COPD patients: a correlation and diagnosis analysis
Average TLC%pred (A), RV%pred (B), and RV/TLC (C) as measured by whole-body plethysmography and multi-breath helium dilution, varying by severity. The results are plotted as means ± SD; Differences between body plethysmography and helium dilution methods were analyzed with paired T-test. †p < 0.001, ‡p < 0.05. he, helium dilution; pleth, plethysmography; TLC, total lung capacity; RV, residue volume.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120321&req=5

f1: Average TLC%pred (A), RV%pred (B), and RV/TLC (C) as measured by whole-body plethysmography and multi-breath helium dilution, varying by severity. The results are plotted as means ± SD; Differences between body plethysmography and helium dilution methods were analyzed with paired T-test. †p < 0.001, ‡p < 0.05. he, helium dilution; pleth, plethysmography; TLC, total lung capacity; RV, residue volume.
Mentions: A total of 170 patients were included into this prospective study. All patients were confirmed with stable COPD according to GOLD standards1. None of the patients had an acute exacerbation during previous 4 weeks before pulmonary function tests, and all medications which may alter lung function were stopped for at least 72 hours. Pulmonary function variables are performed in Table 1 and Fig. 1. The subject population included 44 patients (25.9%) with GOLD Classification 1, 54 patients (31.8%) with GOLD Classification 2, 34 patients (20.0%) with GOLD Classification 3, and 38 patients (22.3%) with GOLD Classification 4.

View Article: PubMed Central - PubMed

ABSTRACT

Chronic obstructive pulmonary disease (COPD) is a chronic airway disease characterized by persistent airflow limitation. Moreover, lung hyperinflation evaluated by lung volumes is also the key pathophysiologic process during COPD progression. Nevertheless, there is still no preferred method to evaluate lung volumes. For this study, we recruited 170 patients with stable COPD to assess lung volumes stratified by airflow limitation severity. Lung volumes including residual volume (RV) and total lung capacity (TLC) were determined by both body plethysmography and helium dilution methods. The discrepancies between these two methods were recorded as &Delta;RV%pred, &Delta;TLC%pred, and &Delta;RV/TLC. We found that &Delta;RV%pred, &Delta;TLC%pred, and &Delta;RV/TLC increased significantly with the severity of COPD. The differences of lung capacity between these two methods were negatively correlated with FEV1%pred, and diffusing capacity for carbon monoxide (DLCO%pred). Moreover, the receiver operating characteristic (ROC) for &Delta;TLC%pred to distinguish severe COPD from non-severe COPD had an area under curve (AUC) of 0.886. The differences of lung volume parameters measured by body plethysmography and helium dilution methods were associated with airflow limitation and can effectively differentiate COPD severity, which may be a supportive method to assess the lung function of stable COPD patients.

No MeSH data available.