A retrospective analysis recently published in Lung demonstrated differences in residual volume (RV) measurements between hospitals in patients with severe emphysema, thus emphasizing the importance of accurately performing body plethysmography measurements.

Bronchoscopic lung volume reduction (BLVR) is a valid treatment option for patients with severe emphysema who have severe static lung hyperinflation (defined as a RV >175% of the predicted volume). Although body plethysmography is the preferred method to measure RV in patients with severe emphysema, a team of researchers noted that in their hospital, a BLVR expert center, they frequently observe patients with a lower RV value compared with the value measured in their referring hospital, even though both are measured by body plethysmography.

If the RV value is too low for BLVR treatment, this may lead to disappointment of the patient and their caregivers, as well as to unnecessary, time-consuming, and expensive hospital visits, and possibly even to wrong treatment selection.

Therefore, the researchers retrospectively analyzed 300 patients with severe emphysema to determine to what degree RV and other pulmonary function measurements matched between referring hospitals and their hospital. They found a median RV of 4.47 (range, 1.70-7.57), which was a median 130 mL lower than in the referring hospitals (range, -3.04 to +1.94; P <.001). Of the patients with an RV >175% of predicted threshold in their referring hospital, 11% (n=34) were not accepted for BLVR because of an RV <175% of predicted threshold when re-measured in the researchers’ hospital.

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“In conclusion, this retrospective analysis demonstrated differences in RV measurements between different hospitals in patients with severe emphysema,” stated the authors. “Overestimation of RV can lead to unnecessary referrals for BLVR and potential treatment failures.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Welling JBA, Hartman JE, Ten Hacken NHT, et al. Significant differences in body plethysmography measurements between hospitals in patients referred for bronchoscopic lung volume reduction [published on August 31, 2019]. Lung. doi:10.1007/s00408-019-00265-w