Abstract
To investigate the mechanism of airflow limitation before and 6 and 12 months after targeted emphysematous resection in 10 male patients aged 67 +/- 8 years (mean +/- SD) with very severe COPD undergoing bilateral thoracoscopic stapling techniques. Lung function, including static lung elastic recoil, was measured 2 weeks before and 6 and 12 months after surgery. Twelve months after surgery, there was a significant (p < 0.001) reduction in total lung capacity (TLC), 9.5 +/- 0.3 L (mean +/- SEM) to 8.5 +/- 0.3 L, functional residual capacity, and residual volume. Airway conductance and FEV1, 0.71 +/- 0.1 L (mean +/- SEM) to 0.95 +/- 0.1 L, improved significantly (p < 0.01). Lung elastic recoil increased markedly at TLC from 11.7 +/- 0.7 cm H2O (mean +/- SEM) to 15.0 +/- 1.0 cm H2O (p < 0.01) as did maximum expiratory airflow in every patient. However, when compared with data obtained in each patient at 6 months, lung volumes are significantly increased, and expiratory airflow and lung elastic recoil pressures are significantly reduced (p < or = 0.05). Analysis of maximum expiratory flow-static elastic recoil pressure curve indicates conductance of the S airway segment (Gs) increased from 0.20 +/- 0.03 L/s/cm H2O (mean +/- SEM) to 0.28 +/- 0.04 L/s/cm H2O (p < 0.02), and critical transmural pressure in the collapsible segment (Ptm') decreased from 3.2 +/- 0.2 cm H2O (mean +/- SEM) to 2.5 +/- 0.2 cm H2O (p < 0.01). The improvement in maximal expiratory airflow can be attributed primarily to increased lung elastic recoil and its secondary effect on enlarging airway diameter causing increased airway conductance, increased Gs, and decreased Ptm'. The improvement in lung function and elastic recoil peaks at 6 months.
Highlights
When compared with data obtained in each patient at 6 months, lung volumes are significantly increased, and expiratory airflow and lung elastic recoil pressures are significantly reduced (p:50.05)
The improvement in lung function and elastic recoil peaks at 6 months. (CHEST 1996; 110:1407-15)
Results in the present study extend our earlier short-term (6 months) observations.l4.l5 Marked clinical and physiologic improvement persists in lung function at 1 year following bilateral targeted excision of severely emphysematous areas in patients with very severe expiratory airflow limitation
Summary
We consecutively studied 14 patients (12 men) aged 67::'::8 years (mean::'::SD ). Four patients refused to undergo repeated esophageal b alloon studies at 12 months. We report complete data o nlO male patients. As previously described,14·15 all the patients who underwent the r rocedure were markedly symptomatic with grade 2::3 dyspnea,[1] with severe Hxed expiratory obstruction that h ad n otimproved d espite appropriate therapeutic interventions, including oxygen, antibiotics, aerosol and systemic bronchodilators, cmticosteroids, and pulmona~y rehabilitation. High-resolution, thin-section CT of the lungs demonstrated emphysema scores19·20 2::60 with heterogeneous distribution, ie, predominant emphysematous destruction of upper t o middle lung fields with relative preservation of n ormal lung tissue in the lower lung fields. Standard nuclear medicine ventilation and perfusion lung scans demonstrated similar heterogeneous distribution
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