Central Airway Resistance in Excised Emphysematous Lungs

¹ Research Physiologist, Webb-Waring Lung Institute, University of Colorado Medical Center
² Assistant Professor of Pathology, University of Colorado School of Medicine
³ Associate Professor of Medicine, University of Colorado School of Medicine
⁴ Professor of Medicine, University of Colorado School of Medicine

We ventilated 23 excised lungs in an artificial thorax (—20 cm H₂O for 2-sec inspiration, +10 cm H₂O for 2-sec expiration) and made simultaneous cinebronchograms, to assess dynamic airway collapse on expiration. To determine airways resistance at the same time, we used Macklem's retrograde catheter technique to divide the bronchial tree into peripheral airways, those less than 2 to 3 mm in diameter, and central airways, those larger than 2 to 3 mm in diameter. Collapse of central airways was associated, in most of the 16 cases measured, with a sustained elevation in expiratory peripheral airway resistance. Central expiratory airway resistance rose coincident with collapse in most cases and remained elevated for the remainder of the cycle.