Determining Static Hyperinflation in Patients with Severe Emphysema: Relation Between Lung Function Parameters and Patient-Related Outcomes

Wouter W de Weger, Karin Klooster, Nick H Ten Hacken, Marlies van Dijk, Jorine E Hartman, Dirk-Jan Slebos*

*Corresponding author for this work

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Abstract

Background Bronchoscopic lung volume reduction techniques are minor invasive treatment modalities for severely hyperinflated emphysema patients. The severity of static lung hyperinflation determines eligibility and success rate for these treatments. However, it is not exactly known what parameter should be used to optimally reflect hyperinflation. Commonly used parameters are residual volume (RV) and the RV/Total lung capacity (TLC) ratio. Other parameters reflecting hyperinflation are Inspiratory Capacity/TLC and forced vital capacity. Objectives To define which of these function parameters is the most optimal reflection of hyperinflationin in relation to patient-related outcomes. Methods In a retrospective cohort study, data from measurements during baseline visits of eight studies were pooled. Primary outcomes were RV/TLC ratio and RV as percentage of predicted (RV%pred), both measured by bodyplethysmography, compared to the patient-related outcome variables: 6-min walk distance (6MWD), the St. George's Respiratory Questionnaire (SGRQ), and the modified Medical Research Council (mMRC). Results Two hundred seventy-four COPD patients (mean age 59 years; 66% female), FEV(1)0.74 +/- 0.28 L, RV 4.94 +/- 1.06 L, 6MWD of 339 +/- 95 m, were included in the analysis. Significant correlations (allp <0.01) were found between RV%pred and 6MWD (r = - 0.358), SGRQ (r = 0.184), and mMRC (r = 0.228). Also, there was a significant correlation between RV/TLC ratio and 6MWD (r = - 0.563), SGRQ (r = 0.289) and mMRC (r = 0.354). Linear regression analyses showed that RV/TLC ratio was a better predictor of patient outcomes than RV%pred. Conclusion This study demonstrates that both RV/TLC ratio and RV%pred are relevant indicators of hyperinflation in patients with severe emphysema in relation to patient-related outcomes. RV/TLC ratio is more strongly related to the patient-related outcomes than RV%pred.

Original languageEnglish
Pages (from-to)629-636
Number of pages8
JournalLung
Volume198
Issue number4
DOIs
Publication statusPublished - 28-Jun-2020

Keywords

  • Hyperinflation
  • Emphysema
  • Residual volume
  • Lung volume reduction
  • COPD
  • OBSTRUCTIVE PULMONARY-DISEASE
  • VOLUME-REDUCTION SURGERY
  • SMALL-AIRWAY OBSTRUCTION
  • HOMOGENEOUS EMPHYSEMA
  • COIL TREATMENT
  • 6-MINUTE WALK
  • INTERVENTIONS
  • SPIROMETRY
  • THERAPY
  • TRIAL

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