CHANGES IN PULMONARY PHYSIOLOGY AFTER LUNG-VOLUME REDUCTION SURGERY IN A RABBIT MODEL OF EMPHYSEMA

Objective: The purpose of this study is to investigate the effects of lung volume reduction surgery on pulmonary compliance, airway how, and helium lung volumes in an elastase-induced emphysema animal model, Me thods: A 15,000-unit bolus of elastase was aerosolized through an endo tracheal tube in 14 New Zealand White rabbits to induce emphysema, Sta pled lung volume reduction of bilateral upper and middle lobes was per formed through a midline sternotomy at 1 weeks after induction of emph ysema. Lung functions were measured at baseline before induction of em physema, preoperatively at 4 weeks, and 1 week postoperatively. Result s: Compliance increased after induction of emphysema and decreased in response to lung volume reduction surgery. Functional residual capacit y decreased after lung volume reduction surgery in proportion to the a mount of excised lung tissue. Expired flows suggested improvement in r esponse to lung volume reduction surgery, Histologic examination confi rmed presence of diffuse heterogeneous emphysema in each animal at nec ropsy. Conclusions: The decreased compliance and increased airway flow after volume reduction surgery in this model parallels findings in hu man studies and suggests that similar mechanisms of increased elastic recoil and airway support contribute to improvement.