THE INFLUENCE OF LUNG-VOLUME REDUCTION SURGERY ON VENTILATORY MECHANICS IN PATIENTS SUFFERING FROM SEVERE CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Recently, lung volume reduction ([LVR] removal of about 20% of lung vo lume), has been performed to treat severe emphysema. Little is known, however, about the mechanism and time course of functional improvement , and the reasons that such patients can be tracheally extubated very early. Therefore, we studied changes in ventilatory mechanics in 12 pa tients after LVR. Measurements of work of breathing (WOB), intrinsic p ositive end-expiratory pressure (PEEPi), dynamic compliance (Cdyn), an d mean airway resistance (Rawm) were performed the day before surgery, early postoperatively, and 1 and 3 mo after surgery. All measurements were performed on tracheally extubated patients, simultaneously asses sing esophageal pressure via esophageal balloon catheter and air flow via tightly adjusted mask. Standard spirometry was assessed preoperati vely and 1 and 3 mo postoperatively. The patients presented with force d expiratory volume in 1 s (FEV(1)) of 670+/-50 mL and pathological va lues of WOB and PEEPi. All patients were successfully tracheally extub ated within 5 h postoperatively. Immediately thereafter, a marked and sustained decrease in WOB, PEEPi, and Rawm was noted, as well as an in crease in Cdyn. Ventilatory mechanics improved immediately after LVR, probably due to decompression of lung tissue, thereby enabling success ful tracheal extubation.