Scripties UMCG - Rijksuniversiteit Groningen
English | Nederlands

Determining static hyperinflation in patients with severe emphysema: impact of different measurements on patient outcomes

(2017) Wege, W.W. de (Wouter)

Background: Bronchoscopic lung volume reduction techniques are new minor invasive
treatment modalities for severe emphysema patients. The degree of lung hyperinflation,
caused by the emphysema component drives the response to this treatment. However, no
exact method to best define hyperinflation is available. The aim of this study was to find a
way to determine hyperinflation in a more precise manner.
Methods: In a retrospective cohort study data of eight studies were pooled. Measurements
during baseline visits were included. Primary outcomes were RV/TLC ratio and RV as
percentage of the predicted value (RV%pred) compared to the patient related outcome
variables: 6-minute walk test (6MWT, exercise capacity), the St. George’s Respiratory
Questionnaire (SGRQ, quality of life) and the modified Medical Research Council (mMRC,
dyspnea severity score).
Results: Two hundred seventy-four patients were included in the analysis (mean age 59 years;
66% was female). Correlations were found between RV%pred and 6MWT (r = -0.358,
p <0.001), RV%pred and SGRQ (r = 0.184, p = 0.002) and RV%pred and mMRC (r = 0.228,
p <0.001). Also, there was a correlation between RV/TLC and 6MWT (r = -0.563, p <0.001),
RV/TLC ratio and SGRQ (r = 0.289, p <0.001) and RV/TLC ratio and mMRC (r = 0.354,
p <0.001). When comparing with SGRQ, ANOVA showed more significant differences
between 6MWT and RV/TLC ratio and RV%pred. Using linear regression analyses, it can be
concluded RV/TLC ratio and RV%pred both are significant independent predictors of
Conclusion: The results of this study confirm that both RV/TLC ratio and RV%pred are
relevant indicators of hyperinflation in patients with severe emphysema, with RV/TLC ratio
being the best predictor of the variation in 6MWT.

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