Abstract Rationale Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. In its advanced form, irreversible airway narrowing and alveolar destruction leads to emphysema and gas-trapping, which is associated with significant respiratory disability, increased healthcare utilization, and increased mortality. Lung volume reduction (LVR) procedures to reduce hyperinflation are recommended internationally and are commissioned in the United Kingdom. Surgical LVR or bronchoscopic LVR with endobronchial valves reduce hyperinflation, improve chest wall mechanics and enable more efficient ventilation. This improves breathlessness, quality of life and exercise capacity. Residual volume (RV) is a key physiological measure to assessing hyperinflation and select patients for LVR treatments, where a threshold 150% predicted is suggested3. RV testing using body plethysmography is mostly available in specialized lung function laboratories requiring secondary care referral. A non-invasive RV calculator, developed by Evankovich et al., modified by Pulmonx, allows modelling of spirometry results to predict RV values 150% predicted, and therefore identify patients who may be eligible for LVR. Methods A database of community patients enrolled for digital health monitoring for COPD, who had all consented for data sharing, was interrogated for spirometric and demographic values including Forced Expiratory Volume in 1 second (FEV1), Forced Vital Capacity (FVC), age, height, and gender. These values were inputted into the RV predictor calculator and outputs which met the predefined threshold of 75% chance of RV 150% predicted were identified. Results The database comprised of 870 individual records. One result was excluded due to inaccurate spirometric values. 664 records with complete datasets were inputted into the RV calculator. 56/664 (8.4%) patients reached ≥75% threshold predicting an RV 150% predicted. Identified patients (25 females, 31 males) had a mean age of 63 years with mean FEV1 0.89litres, FVC 2.29litres, and FEV1/FVC ratio 0.41. Conclusions The RV calculator, a non-invasive screening tool utilizing simple spirometry measures to estimate residual volume, identified 8.4% of individuals in a community based COPD cohort to have probable severe hyperinflation, potentially qualifying for LVR procedure evaluation. This tool thus enables earlier detection of patients, who may potentially benefit from life changing LVR treatments. We plan to invite the individuals identified by the RV calculator for specialist respiratory review in a secondary care setting, with further outcome data to be collected and presented. This abstract is funded by: None
Hambleton et al. (Fri,) studied this question.