Technical advances: measurement of collateral flow in the lung with a dedicated endobronchial catheter system.

Interest in assessment of collateral flow measurement has resurfaced with the advent of endoscopic lung volume reduction studies, namely valve technologies (eg Emphasys EBV), that achieve volume reduction through lobar isolation. It is currently thought that collateral ventilation could be a contributing factor for endoscopic lung volume reduction failures, as isolated lobes can "backfill" through these channels. In an attempt to quantify collateral ventilation, the Chartis System has been developed by Pulmonx, Inc. to measure pressure and flow, and calculate resistance to airflow through collateral channels in isolated lung compartments.