Lung function 5 yr after lung volume reduction surgery for emphysema.

Current datum more than 2 yr after lung volume reduction surgery (LVRS) for emphysema is limited. This prospective study evaluates pre-LVRS baseline and 5-yr results in 26 symptomatic patients (mean age 67 +/- 6 yr) (mean +/- SD) who underwent bilateral, targeted upper lobe stapled LVRS using video-assisted thoracoscopy. Baseline forced expiratory volume in 1 s (FEV(1)) was 0.7 +/- 0.2 L (mean +/- SD), 29 +/- 10% predicted. Following LVRS, with none lost to follow-up, mortality due to respiratory failure at 0.5, 1, 2, 3, 4, and 5 yr was 4%, 4%, 19%, 31%, 46%, and 58%, respectively. Increase above baseline for FEV(1) > 200 ml and/or FVC > 400 ml at 1, 2, 3, 4, and 5 yr post-LVRS was noted in 73%, 46%, 35%, 27%, and 8% of all patients; decrease in dyspnea grade >/= 1 in 88%, 69%, 46%, 27%, and 15%; and elimination of initial oxygen dependence in 18 patients in 78%, 50%, 33%, 22%, and 0%, respectively. Expiratory airflow improved due to the increase in both lung elastic recoil and small airway intraluminal caliber. Five patients decreased FEV(1) 141 +/- 60 ml/yr and FVC 102 +/- 189 ml/yr over 3.8 +/- 1.2 yr post-LVRS, similar to their pre-LVRS rate of decline. In the 11 patients who survived 5 yr, at 0.5-1.0 yr post-LVRS peak increase in FEV(1) was 438 +/- 366 ml, with a decline of 149 +/- 157 ml the following year and 78 +/- 59 ml/yr over 4.0-4.5 yr. Bilateral LVRS provided palliative clinical and physiological improvement in 9 of 26 patients at 3 yr, 7 at 4 yr, and 2 at 5 yr.

Unsuspected pseudophysiologic emphysema in chronic persistent asthma.

The current literature emphasizes the role of airway remodeling in chronic persistent asthma and its putative effect on causing fixed expiratory airflow limitation. We studied 18 adults with chronic persistent asthma; 12 men, six women, age 59 +/- 15 yr (mean +/- SD) with fixed expiratory airflow obstruction. We measured lung elastic recoil and examined the mechanism of expiratory airflow limitation. Diaphragmatic strength was also measured in six asthmatics, using both sniff and partially occluded airway technique. All 18 asthmatics had markedly abnormal maximal expiratory flow-volume curves at both high and low lung volumes. Hyperinflation was present at residual volume (RV), FRC, and TLC in all subjects. Diffusing capacity was normal or elevated and lung computed tomography (CT) was normal in all 18 asthmatic subjects. There was a significant loss of lung elastic recoil in three of four asthmatics age 30 to 49, all five age 51 to 60 yr, and seven of nine age 61 to 82 yr. Maximal expiratory airflow limitation in only four elderly asthmatics and only at low lung volumes was due completely to loss of lung elastic recoil. In the others, we estimate the reduction in lung elastic recoil was responsible for 35% reduction in maximal expiratory airflow at 80% of TLC, and 55% at 70% of TLC. Despite hyperinflation, transdiaphragmatic pressures and strength were normal. The mechanisms responsible for loss of lung elastic recoil remain elusive. The high incidence of loss of lung elastic recoil in chronic persistent asthma was unexpected, and its contribution to abnormal lung function needs to be emphasized.

Relationship between amount of lung resected and outcome after lung volume reduction surgery.

BACKGROUND: Lung volume reduction surgery (LVRS) is being actively investigated for palliative treatment of severe emphysema. Considerable focus is directed toward patient selection and outcomes of LVRS. However, there is little information available regarding surgical methods to guide optimal extent of resection. We hypothesized that acute improvement and long-term survival after bilateral staple LVRS would be related to the extent of tissue resected. METHODS: The relationship between acute improvement in forced expiratory volume in 1 second and forced vital capacity was examined as a function of the total grams of lung tissue resected in 237 patients who underwent bilateral staple LVRS by a single group of surgeons. Overall survival was assessed based on extent of resection by quartiles of tissue weight resected using Kaplan-Meier survival methods. RESULTS: Improvement in forced expiratory volume in 1 second and forced vital capacity correlated with extent of tissue resected (p < 0.01), although there was considerable variability to individual response (r = 0.3). In contrast, there was no apparent relationship between the amount of tissue resected and overall postoperative survival (p = 0.7). CONCLUSIONS: There is a correlation between the amount of tissue resected and improvement in forced expiratory volume in 1 second and forced vital capacity after bilateral staple LVRS, with generally greater postoperative improvement after larger volume resections. However, there does not appear to be greater long-term survival with larger volume resections despite greater improvement in spirometry. This study suggests that factors other than improvement in spirometric variables may govern optimal LVRS resection volumes and long-term outcome. Future studies will clearly be needed in this important area of LVRS emphysema research.

Lung function 4 years after lung volume reduction surgery for emphysema.

STUDY OBJECTIVES: Current data for patients > 2 years after lung volume reduction surgery (LVRS) for emphysema is limited. This prospective study evaluates pre-LVRS baseline data and provides long-term results in 26 patients. INTERVENTION: Bilateral targeted upper lobe stapled LVRS using video thoracoscopy was performed in 26 symptomatic patients (18 men) aged 67 +/- 6 years (mean +/- SD) with severe and heterogenous distribution of emphysema on lung CT. Lung function studies were measured before and up to 4 years after LVRS unless death intervened. RESULTS: No patients were lost to follow-up. Baseline FEV(1) was 0.7 +/- 0.2 L, 29 +/- 10% predicted; FVC, 2.1 +/- 0.6 L, 58 +/- 14% predicted (mean +/- SD); maximum oxygen consumption, 5.7 +/- 3.8 mL/min/kg (normal, > 18 mL/min/kg); dyspneic class > or = 3 (able to walk < or = 100 yards) and oxygen dependence part- or full-time in 18 patients. Following LVRS, mortality due to respiratory failure at 1, 2, 3, and 4 years was 4%, 19%, 31%, and 46%, respectively. At 1, 2, 3, and 4 years after LVRS, an increase above baseline for FEV(1) > 200 mL and/or FVC > 400 mL was noted in 73%, 46%, 35%, and 27% of patients, respectively; a decrease in dyspnea grade > or = 1 in 88%, 69%, 46%, and 27% of patients, respectively; and elimination of oxygen dependence in 78%, 50%, 33%, and 22% of patients, respectively. The mechanism for expiratory airflow improvement was accounted for by the increase in both lung elastic recoil and small airway intraluminal caliber and reduction in hyperinflation. Only FVC and vital capacity (VC) of all preoperative lung function studies could identify the 9 patients with significant physiologic improvement at > 3 years after LVRS, respectively, from 10 patients who responded < or = 2 years and died within 4 years (p < 0.01). CONCLUSIONS: Bilateral LVRS provides clinical and physiologic improvement for > 3 years in 9 of 26 patients with emphysema primarily due to both increased lung elastic recoil and small airway caliber and decreased hyperinflation. The 9 patients had VC and FVC greater at baseline (p < 0.01) when compared to 10 short-term responders who died < 4 years after LVRS.

Survival after unilateral versus bilateral lung volume reduction surgery for emphysema.

OBJECTIVE: Bilateral staple lung volume reduction surgery (LVRS) immediately improves pulmonary function and dyspnea symptoms in patients with advanced heterogeneous emphysema to a greater degree than do unilateral procedures. However, the long-term outcome after these surgical procedures needs to be critically evaluated. We compare 2-year survival of patients who underwent unilateral versus bilateral video-assisted LVRS in a large cohort treated by a single surgical group. METHODS: The cases of all 260 patients who underwent video-assisted thoracoscopic stapled LVRS from April 1994 to March 1996 were analyzed to compare results after unilateral versus bilateral procedures. Overall survival was calculated by Kaplan-Meier methods; Cox proportional hazard methods were used to adjust for patient heterogeneity and baseline differences between groups. RESULTS: Overall survival at 2 years was 86.4% (95% CI 80. 9%-91.8%) after bilateral LVRS versus 72.6% (95% CI 64.2%-81.2%) after unilateral LVRS (P =.001 for overall survival comparison). Improved survival after bilateral LVRS was seen among high- and low-risk subgroups as well. Average follow-up time was 28.5 months (range, 6 days to 46.6 months) for the bilateral LVRS group and 29.3 months (range, 6 days to 45.0 months) for the unilateral LVRS patients. CONCLUSIONS: Comparison of unilateral versus bilateral thoracoscopic LVRS procedures for the treatment of emphysema reveals that bilateral LVRS by video-assisted thoracoscopy resulted in better overall survival at 2-year follow-up than did unilateral LVRS. This survival study, together with other studies demonstrating improved lung function after bilateral LVRS, suggests that bilateral surgery appears to be the procedure of choice for patients undergoing LVRS for most eligible patients with severe heterogeneous emphysema.

Lung function after bilateral lower lobe lung volume reduction surgery for alpha1-antitrypsin emphysema.

This study explores the mechanism(s) of airflow limitation following lung volume reduction surgery (LVRS) in patients with emphysema due to homozygous alpha1-antitrypsin (AT) deficiency. Bilateral targeted lower lobe stapled LVRS using video thoracoscopy was performed in six patients (five males) aged 61+/-9 yrs (mean+/-SD) with alpha1-AT emphysema. Two patients received only a 6-month follow-up. However, four patients, at 22, 24, 27 and 36 months post-LVRS, noted relief from dyspnoea and increased walk tolerance. At 27+/-6 months (mean+/-SD) post-LVRS, their forced expiratory volume in one second improved only from 30+/-2% of the predicted value (mean+/-SEM) before surgery to 33+/-1% pred after surgery. Yet, total lung capacity (TLC) decreased from 151+/-13 to 127+/-10% pred; diffusing capacity increased from 35+/-9 to 59+/-9% pred; and vital capacity increased from 68+/-10 to 88+/-5% pred. In three patients, static lung elastic recoil at TLC increased from 1.1+/-0.15 to 1.2+/-0.10 kPa. Using flow/pressure curves, the mechanism for expiratory airflow limitation pre-LVRS and the improvement noted post-LVRS could be primarily accounted for by the initial loss and subsequent increase in lung elastic recoil. Bilateral lung volume reduction surgery provides modest physiologic improvement for 2-3 yrs in patients with alpha1-antitrypsin emphysema due to increases in lung elastic recoil.

Survival following bilateral staple lung volume reduction surgery for emphysema.

STUDY OBJECTIVES: Despite numerous reports of short-term response to lung volume reduction surgery (LVRS) for treatment of emphysema, to our knowledge, longer-term survival has not been reported. We describe survival following LVRS in a large cohort of 256 patients treated with bilateral staple LVRS (n = 236 video-assisted thoracic surgery [VATS] approaches, n = 20 median sternotomy) by a single group of physicians over a 3 1/2-year period from April 1994 to November 1997. DESIGN: Prospective survival study. Overall survival, survival stratified by preoperative presentation, and acute postoperative response were investigated using Kaplan-Meier methods. The simultaneous effects of preoperative predictors and postoperative response variables on survival were examined using a Cox proportional hazards model. SETTING: Community hospital and university medical center. PATIENTS: We studied 256 consecutive patients with severe emphysema treated with LVRS. INTERVENTIONS: Bilateral staple LVRS by VATS. MEASUREMENTS AND RESULTS: Overall survival information was known with certainty for 246 of 256 patients as of February 1, 1998. Median follow-up time was 623 days (range, 0 to 1,545 days). Mean FEV1 was 0.635L+/-0.015 L preoperatively and rose to 1.068L+/-0.029 L postoperatively. By standard analysis methods (missing patients censored at the time of last contact), 1-year survival was 85+/-2.3% compared with 83+/-2.4% 1-year survival with "worst case" analytic methods (assuming all missing patients died). Two-year survival averaged 81+/-2.7% by standard analysis vs 76+/-2.9% by worst case evaluation. Survival was significantly better for patients who were younger (< or = 70 years old, p = 0.02) and with higher baseline FEV1 (> 0.5, p < 0.03) and PO2 (> 54, p < 0.001). Patients who had greatest short-term improvement in FEV1 following surgery (> 0.56 L increase) also had significantly better longer-term survival following LVRS. CONCLUSIONS: To our knowledge, this is the first longer-term survival analysis of a large series of patients who underwent bilateral staple LVRS for emphysema. Substantial long-term mortality is seen, particularly within identifiable high-risk subgroups. Careful comparison to comparably matched control patients will be needed to definitively assess the benefits and risks of LVRS. This study suggests that prospective, controlled trials may need to stratify patient randomization based on preoperative risk factors to obtain meaningful results.

Pseudophysiologic emphysema resulting from severe small-airways disease.

Loss of lung elastic recoil causing hyperinflation with increased TLC and decreased diffusing capacity and expiratory airflow are physiologic hallmarks of emphysema. We studied lung mechanics in 10 patients (seven men and three women) aged 69 +/- 9 yr (mean +/- SD) who had fixed, severe expiratory airflow limitation with a mean FEV1 = 0.73 +/- 0.1 L (mean +/- SD) (32 +/- 7% predicted) and lung computed tomographic picture grade score <= 20, indicating no or trivial emphysema. Three patients died, in whom whole-lung emphysema scores were 15 each and small airways were abnormal. Marked hyperinflation was present in all 10 patients studied, with TLC 7.3 +/- 1.1 L (140 +/- 12% predicted); FRC 5.6 +/- 0.8 L (177 +/- 30% predicted); and RV 5.2 +/- 0.8 L (242 +/- 28% predicted). Diffusing capacity of carbon monoxide (DLCO was reduced, at 12 +/- 6 ml/min/mm Hg (61 +/- 29% predicted). The pressure-volume curves of the lung were markedly abnormal. Pst(L) at TLC was 11.6 +/- 1.4 cm H2O. Transdiaphragmatic pressure (Pdi) in five patients was 66 +/- 13 cm H2O. These results indicate that severe small-airways disease with no or trivial emphysema may cause a spurious reduction in diffusing capacity as well as severe loss of lung elastic recoil resulting in marked hyperinflation, increased TLC, and decreased Pdi and expiratory airflow.

Serial lung function and elastic recoil 2 years after lung volume reduction surgery for emphysema.

STUDY OBJECTIVE: To evaluate serial lung function studies, including elastic recoil, in patients with severe emphysema who undergo lung volume reduction surgery (LVRS). To determine mechanism(s) responsible for changes in airflow limitation. METHODS: We studied 12 (10 male) patients aged 68+/-9 years (mean+/-SD) 6 to 12 months prior to and at 6-month intervals for 2 years after thoracoscopic bilateral LVRS for emphysema. RESULTS: At 2 years post-LVRS, relief of dyspnea remained improved in 10 of 12 patients, and partial or full-time oxygen dependency was eliminated in 2 of 7 patients. There was significant reduction in total lung capacity (TLC) compared with pre-LVRS baseline, 7.8+/-0.6 L (mean+/-SEM) (133+/-5% predicted) vs 8.6+/-0.6 L (144+/-5% predicted) (p=0.003); functional residual capacity, 5.6+/-0.5 L (157+/-9% predicted) vs 6.7+/-0.5 L (185+/-10% predicted) (p=0.001); and residual volume, 4.9+/-0.5 L (210+/-16% predicted) vs 6.0+/-0.5 L (260+/-13% predicted) (p=0.000). Increases were noted in FEV1, 0.88+/-0.08 L (37+/-6% predicted) vs 0.72+/-0.05 L (29+/-3% predicted) (p=0.02); diffusing capacity, 8.5+/-1.0 mL/min/mm Hg (43+/-3% predicted) vs 4.2+/-0.7 mL/min/mm Hg (18+/-3% predicted) (p=0.001); static lung elastic recoil pressure at TLC (Pstat), 13.7+/-0.5 cm H2O vs 11.3+/-0.6 cm H2O (p=0.008); and maximum oxygen consumption, 8.7+/-0.8 mL/min/kg vs 6.9+/-1.5 mL/min/kg (p=0.03). Increase in FEV1 correlated with the increase in TLC Pstat/TLC (r=0.75, p=0.03), but not with any baseline parameter. CONCLUSION: Two years post-LVRS, there is variable clinical and physiologic improvement that does not correlate with any baseline parameter. Increased lung elastic recoil appears to be the primary mechanism for improved airflow limitation.

Rate of FEV1 change following lung volume reduction surgery.

INTRODUCTION: Lung volume reduction surgery (LVRS) improves pulmonary function and dyspnea symptoms acutely in selected patients with heterogeneous emphysema. Limited data are available regarding long-term function following LVRS. We analyzed short-term (<6 months) and long-term rate of change of pulmonary function in 376 patients who underwent unilateral or bilateral LVRS using thoracoscopic or median sternotomy, staple, laser, or combined techniques. We hypothesized that the long-term rate of deterioration in lung function would be dependent on the surgical procedure used and would be greatest in those with the largest short-term postoperative improvement. METHODS: Pulmonary function was assessed preoperatively and at repeated intervals following LVRS. The change in pulmonary function over time was assessed for each patient by determining the individual change in FEV1 using linear regression analysis short and long term. Overall rate of change in pulmonary function was calculated for the composite group of patients and subgrouped by operative procedure. RESULTS: Lung function appears to improve in the first few months following LVRS in most patients, maximizing at approximately 3 to 6 months and declining thereafter. The short-term incremental improvement following staple procedures is superior to improvements following laser procedures or unilateral surgery: FEV1 increase (mean+/-SD) of 0.39+/-0.03 L for bilateral staple, 0.25+/-0.03 L for unilateral staple, 0.10+/-0.03 L for unilateral laser, and 0.22+/-0.1 L for mixed unilateral staple/laser procedures. However, the long-term rate of decline in FEV1 was greatest for bilateral staple LVRS procedures as well: 0.255+/-0.057 L/yr for bilateral staple, 0.107+/-0.068 L/yr for unilateral staple, 0.074+/-0.034 L/yr for unilateral laser, and 0.209+/-0.12 L/yr for mixed staple laser procedures. There was a general correlation between the magnitude of short-term incremental improvement and the rate of deterioration in FEV1 (r=0.292, p=0.003). CONCLUSIONS: While bilateral staple LVRS procedures lead to greater short-term improvement in FEV1, the more rapid rate of FEV1 decline in these patients and the general association between greater short-term incremental improvement and higher rates of deterioration raise questions regarding optimal long-term procedures. Further studies will be needed to answer these important questions.

Dyspnea response following bilateral thoracoscopic staple lung volume reduction surgery.

PURPOSE: Lung volume reduction surgery (LVRS) has shown promise for treating patients with severe emphysema in recent clinical trials. However, response following surgery is difficult to assess due to frequent discrepancies between subjective and objective outcomes. We evaluated the relationship between improvement in dyspnea and pulmonary function response in 145 consecutive patients with inhomogeneous emphysema enrolled in a bilateral thoracoscopic lung volume reduction protocol in order to assess predictors of improved dyspnea outcome and correlation of subjective and objective improvement measures. MATERIALS AND METHODS: Baseline complete pulmonary function testing, spirometry, gas exchange, plethysmography, gas dilution lung volumes, along with resting dyspnea index determinations were performed preoperatively, and repeated short term (mean, 33 days; n=129) and long term (>6 months; mean, 276 days; n=84) following surgery. RESULTS: Improvement in FEV1 percent predicted was significantly associated with improvement in dyspnea scores, though considerable variability exists (r=0.04, p<0.01, short term; r=0.4, p=0.1, long term). In this preselected patient group, those with the extreme degrees of hyperinflation may have less improvement in dyspnea following LVRS than those with milder preoperative hyperinflation. Greater improvement in dyspnea short term and long term was seen in patients with lower presenting residual volume/total lung capacity ratios (r=0.4, p=0.02, short term; r=0.4, p<0.05, long term). CONCLUSIONS: Bilateral thoracoscopic staple LVRS results in significant objective and subjective improvement in patients with severe emphysema and hyperinflation. There was considerable variability between improvement in dyspnea and improvement in spirometry, and preoperative predictors of response may differ between these outcome variables. Further studies are needed to define the long-term implications of these findings.

Patient selection criteria for lung volume reduction surgery.

OBJECTIVE: Our intent was to refine the patient selection criteria for lung volume reduction surgery because various centers have different criteria and not all patients benefit from the procedure. METHODS: Patient information, x-ray results, arterial blood gases, and plethysmographic pulmonary function tests in 154 consecutive patients who underwent bilateral thoracoscopic staple lung volume reduction surgery were compared with clinical outcome (change in forced expiratory volume in 1 second and dyspnea scale) with t tests and analysis of variance. RESULTS: Three hundred thirty-three of 487 (69%) patients evaluated for lung volume reduction surgery were rejected for lack of heterogeneous emphysema (n = 212), medical contraindications (n = 88), hypercapnia (n = 20), uncontrolled anxiety or depression (n = 10), or pulmonary hypertension (n = 1). Two patients died during the evaluation process. When tested by analysis of variance, there was no difference in clinical outcome associated with preoperative forced expiratory volume in 1 second, residual volume, total lung capacity, single-breath diffusing, and arterial oxygen or carbon dioxide tension. All patients selected for the operation had a heterogeneous pattern of emphysema. The upper lobe heterogeneous pattern of emphysema on chest computed tomography and lung perfusion scan was strongly associated with improved outcome with a mean (95% confidence interval) improvement in forced expiratory volume in 1 second of 73.2% (63.3 to 83.1) for the upper lobe compared with a mean (95% confidence interval) improvement of 37.9% (22.9 to 53.0) for the lower lobe or diffuse pattern of emphysema. CONCLUSION: The most important selection criteria for lung volume reduction surgery is the presence of a bilateral upper lobe heterogeneous pattern of emphysema on chest computed tomography and lung perfusion scan. After patients have been selected on the basis of a heterogeneous pattern of emphysema, clinical factors and physiology are not associated with clinical outcome well enough to further refine patient selection criteria. These results do not support the arbitrary patient selection criteria for lung volume reduction surgery reported in the literature.

Lung function 12 months following emphysema resection.

OBJECTIVE: 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. DESIGN: Lung function, including static lung elastic recoil, was measured 2 weeks before and 6 and 12 months after surgery. RESULTS: 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). CONCLUSION: 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.

Should lung volume reduction for emphysema be unilateral or bilateral?

Both unilateral and bilateral lung volume reduction procedures are being advocated for treatment of severe, generalized emphysema. We analyzed the results of 166 consecutive patients who underwent unilateral (n = 87) or bilateral (n = 79) thoracoscopic stapled lung volume reductions to help define the role for these procedures. There was no statistically significant difference in the operative mortality (3.5% vs 2.5%), mean length of stay (11.4 +/- 1 vs 10.9 +/- 1 days), or morbidity for the unilateral and bilateral groups, respectively (p not significant for all variables). Oxygen dependence was eliminated in 18 (36%) of 50 patients who had unilateral procedures and 30 (68%) of 44 of those who had bilateral procedures (p < 0.01). Prednisone was eliminated for 38 (54%) of 51 unilateral-procedure patients, compared with 30 (85%) of 35 bilateral-procedure patients (p = 0.02). Overall, bilateral procedures produced a mean improvement in the forced expiratory volume in 1 second (FEV1) of 57%, compared with 31% for unilateral reduction procedures (p < 0.01). Our bilateral staple procedure produced a 72.8% mean increase in the FEV1 for patients who had upper lobe emphysema. Especially compromised patients (age > or = 75, with preoperative room air Po2 < or = 50 mm Hg or FEV1 < or = 500 ml) had the same morbidity and operative mortality with unilateral or bilateral procedures, but they had a higher 1-year mortality (17% vs 5%), primarily because of respiratory failure after the unilateral operation (p < .001). Although unilateral staple lung volume reduction may produce an excellent result in a given patient, the bilateral procedure appears to be the procedure of choice, because it provides better overall results at no increased morbidity or mortality compared with the unilateral procedure. The results of bilateral staple lung volume reduction by thoracoscopy appear to be comparable to those of median sternotomy.

Combined operations for lung volume reduction surgery and lung cancer.

Fifty-three lung masses were found in 51 (16%) of 325 patients who underwent lung volume reduction surgery. This included 11 non-small cell lung cancers and 42 benign lung masses. Eleven patients (mean age, 69.4 years) underwent a combined lung volume reduction surgery and resection of clinical stage I lung cancers (lymph node dissection with either lobectomy [3] or wedge resection [8]). There were no deaths or major complications. The average length of stay was 8.7 days. The mean FEV1 was 654 mL (21.7% predicted) preoperatively and 1,079 mL (49% predicted) postoperatively. Patients who are screened for lung volume reduction surgery should be carefully evaluated for possible lung masses. Lung volume reduction surgery allows lung cancer surgery in patients who otherwise would be considered to have physiologically inoperable disease.

Mechanism of short-term improvement in lung function after emphysema resection.

We prospectively investigated the mechanism of airflow limitation before and after targeted emphysematous resection in 12 consecutively studied adult patients 68 +/- 4 yr of age (mean +/- SD) with very severe COPD undergoing bilateral thoracoscopic stapling techniques. Lung function, static lung elastic recoil, and airway conductance was measured 2 wk before and 5 to 6 mo after surgery. After surgery, there was a significant (p < 0.01) reduction in TLC (9.3 +/- 0.3 [mean +/- SEM] to 7.7 +/- 0.4 L), functional residual capacity, and residual volume. Airway conductance, FVC, and FEV1 (0.7 +/- 0.1 to 1.2 +/- 0.2 L) all improved significantly (p < 0.01). Lung elastic recoil increased markedly at TLC (from 10.3 +/- 0.5 to 14.6 +/- 1.0 cm H20; p < 0.001) as did maximal expiratory airflow in every patient. Analysis of maximal expiratory flow-static elastic recoil pressure curve indicated that conductance of the S segment (Gs) increased from 0.20 +/- 0.03 (mean +/- SEM) to 0.27 +/- 0.03 L/s/cm H20 (p < 0.01), and the critical transmural pressure (Ptm') decreased from 3.1 +/- 0.2 to 2.4 +/- 0.2 cm H20 (p < 0.02). Mean airway conductance increased from 0.14 to 0.22 L/s/cm H20 (p < 0.01). The improvement in maximal expiratory airflow can be primarily attributed to increased lung elastic recoil and its secondary effect on enlarging airway diameter causing increased airway conductance, increased Gs, and decreased Ptm'.

Contribution of lung and chest wall mechanics following emphysema resection.

OBJECTIVE: To determine the contributions of (1) chest wall (Pcw) and (2) lung elastic recoil pressure (PL) to (3) total elastic recoil pressure exerted by the respiratory system (Prs) in 18 patients (12 men) aged 66 +/- 6 years (mean +/- 1 SD) with severe emphysema who underwent video-assisted thoracoscopic bilateral lung volume reduction surgery under paralyzed (vecuronium) general anesthesia (isoflurane). DESIGN: We measured preoperative and 6-week postoperative lung function studies, and intraoperative inspiratory lung conductance (GL), PL, Pcw, and Prs (cm H2O) at end-expiratory lung volume (EELV), EELV plus 0.60 +/- 0.0 L, and EELV plus 1.15 +/- 0.0 L. All values are mean +/- SEM. RESULTS: Preoperative vs postoperative FVC was 1.9 +/- 0.1 L vs 2.3 +/- 0.1 L (p = 0.03); FEV1 was 0.6 +/- 0.1 L vs 0.9 +/- 0.1 L (p < 0.02); total lung capacity was 7.4 +/- 0.4 L vs 5.9 +/- 0.3 L (p < 0.001); functional residual capacity was 5.7 +/- 0.4 L vs 4.4 +/- 0.2 L (p = 0.001). At EELV preoperative vs postoperative, PL was 0.0 +/- 0.3 vs 1.1 +/- 0.05 (p = 0.04), Pcw was 5.0 +/- 0.7 vs 2.4 +/- 0.9 (p = 0.02), and Prs was 5.0 +/- 0.8 vs 3.5 +/- 0.7 (p = 0.08). AT EELV plus 0.60 L, PL was 3.2 +/- 0.6 vs 6.1 +/- 0.9 (p < 0.001), Pcw was 8.8 +/- 0.8 vs 7.0 +/- 0.9 (p = 0.12), and Prs was 12.0 +/- 0.8 vs 13.1 +/- 0.7 (p = 0.80). At EELV plus 1.15 L, PL was 6.8 +/- 0.9 vs 10.3 +/- 1.1 (p < 0.001), Pcw was 13.5 +/- 1.0 vs 11.2 +/- 1.2 (p = 0.12), and Prs was 20 +/- 1.2 vs 21.5 +/- 1.0 p = 0.93). AT EELV plus 0.06 L, GL was 0.09 +/- 0.00 L/S/cm H2O vs 0.16 +/- 0.01 (p < 0.01). At EELV plus 1.15 L, GL was 0.12 +/- 0.01 vs 0.21 +/- 0.03 (p < 0.05) with similar preoperative vs postoperative GL/PL slopes. CONCLUSION: The increase in PL and decrease in Pcw following LVRS for emphysema may be responsible for the increase in spirometry and airway conductance.

Lung volume reduction surgery for emphysema.

There has been dramatic resurgence of interest in surgical treatment of emphysema, particularly "lung volume reduction" procedures. Recent studies have demonstrated improvements in pulmonary function, lung mechanics, exercise tolerance, and quality of life in selected patients following volume reduction procedures. However, considerable uncertainty remains regarding overall benefit, optimal patient selection, operative techniques, and duration of response. This summarizes current approaches to lung volume reduction surgery, available clinical outcome information, selection criteria, and physiologic mechanisms of response, and discusses the potential role for surgical volume reduction in treatment of emphysema. Recent data appear to support the efficacy of bilateral staple lung volume reduction surgery in patients with severe symptomatic heterogeneously distributed emphysema. Further studies will be needed to determine relative value of different operative techniques and benefit in patients with other clinical presentations.

Use of the Heimlich valve to shorten hospital stay after lung reduction surgery for emphysema.

BACKGROUND: Prolonged air leak is the major complication after lung reduction surgery for emphysema and the major determinant of hospital length of stay. METHODS: Twenty-five of 107 patients (24%) (mean age, 66 years) with an average forced expiratory volume in 1 second of 0.55 L experienced a prolonged air leak (>5 days) after lung reduction surgery. These persistent air leaks were treated by replacing the chest drainage system with Heimlich valves to facilitate earlier hospital discharge even though 64% of the patients had apical air spaces that measured 1 to 7 cm. RESULTS: These patients had a mean postoperative stay of 9.1 days. Chest tubes were then removed an average of 7.7 days later. All apical air spaces resolved, and there were no deaths, empyemas, or pneumonias. CONCLUSIONS: In conclusion, the use of the Heimlich valve after operation for emphysema was associated with minimal morbidity and shortened the mean hospital stay for patients with prolonged air leaks by 46%. This study demonstrates an important concept in the postoperative management of these patients--do not use suction on severely emphysematous lung.