The selection criteria for lung volume reduction
| Referral criteria | Exclusion criteria |
| COPD/emphysema GOLD stage 3 or 4 | Severe bronchiectasis +/− tracheobronchomalacia |
| FEV1 <50% | Smoker |
| TLC >100% | Severe pulmonary artery hypertension as defined (>55 mmHg) |
| RV >150% (due to variation in measuring volumes using helium or body box) | Moderate pulmonary artery hypertension (41–55 mmHg with right ventricular dysfunction) |
| Smoking cessation for a period >3 months | Significant cardiac disease |
| Enrolment into a pulmonary rehabilitation programme (current or in the preceding 12 months) | Severe comorbid illness or malignancy |
| TLCO >20% | Clinically significant bronchiectasis or fibrosis |
GOLD: Global Initiative for Chronic Obstructive Lung Disease; FEV1: forced expiratory volume in 1 s; TLC: total lung capacity; RV: residual volume; TLCO: transfer factor of the lung for carbon monoxide.