Chest
Volume 148, Issue 1, July 2015, Pages 185-195
Journal home page for Chest

Original Research
COPD
Lung Volume Reduction in Emphysema Improves Chest Wall Asynchrony

https://doi.org/10.1378/chest.14-2380Get rights and content
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open access

BACKGROUND

Lung volume reduction (LVR) techniques improve lung function in selected patients with emphysema, but the impact of LVR procedures on the asynchronous movement of different chest wall compartments, which is a feature of emphysema, is not known.

METHODS

We used optoelectronic plethysmography to assess the effect of surgical and bronchoscopic LVR on chest wall asynchrony. Twenty-six patients were assessed before and 3 months after LVR (surgical [n = 9] or bronchoscopic [n = 7]) or a sham/unsuccessful bronchoscopic treatment (control subjects, n = 10). Chest wall volumes were divided into six compartments (left and right of each of pulmonary ribcage [Vrc,p], abdominal ribcage [Vrc,a], and abdomen [Vab]) and phase shift angles (θ) calculated for the asynchrony between Vrc,p and Vrc,a (θRC), and between Vrc,a and Vab (θDIA).

RESULTS

Participants had an FEV1 of 34.6 ± 18% predicted and a residual volume of 217.8 ± 46.0% predicted with significant chest wall asynchrony during quiet breathing at baseline (θRC, 31.3° ± 38.4°; and θDIA, −38.7° ± 36.3°). Between-group difference in the change in θRC and θDIA during quiet breathing following treatment was 44.3° (95% CI, −78 to −10.6; P = .003) and 34.5° (95% CI, 1.4 to 67.5; P = .007) toward 0° (representing perfect synchrony), respectively, favoring the LVR group. Changes in θRC and θDIA were statistically significant on the treated but not the untreated sides.

CONCLUSIONS

Successful LVR significantly reduces chest wall asynchrony in patients with emphysema.

ABBREVIATIONS

3-D
three-dimensional
6MWD
6-min walk distance
Ab
abdominal compartment
BLVR
bronchoscopic lung volume reduction
EELV
end-expiratory lung volume
FRC
functional residual capacity
HRCT
high-resolution CT
IC
inspiratory capacity
LVR
lung volume reduction
LVRS
lung volume reduction surgery
OEP
optoelectronic plethysmography
RC,a
abdominal ribcage compartment
RC,p
pulmonary ribcage
RV
residual volume
SGRQ
St. George's Respiratory Questionnaire
θDIA
phase shift angle between pulmonary ribcage compartmental volume and abdominal ribcage compartmental volume
θRC
phase shift angle between pulmonary ribcage compartmental volume and abdominal ribcage compartmental volume
TLC
total lung capacity
Tlim
exercise time to limitation on cycle ergometer at 75% of the maximum achieved workload on a previous incremental peak exercise test
Vab
abdominal compartmental volume
Vrc,a
abdominal ribcage compartmental volume
Vrc,p
pulmonary ribcage compartmental volume

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FUNDING/SUPPORT: This study was supported by the National Institute for Health Research Respiratory Biomedical Research Unit at the Royal Brompton and Harefield National Health Service Foundation Trust and Imperial College, London who funded the optoelectronic plethysmography assessments and partly funded the salaries of Drs Zoumot and Polkey.

This is a Wellcome-Trust-compliant open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/).