Improvement in pulmonary function and elastic recoil after lung-reduction surgery for diffuse emphysema

Functional improvement after volume reduction: sternotomy versus videoendoscopic approach

BACKGROUND

Volume reduction has been proved to increase ventilatory mechanics in diffuse, nonbullous lung emphysema. However, the best approach is still controversial.

METHODS

We retrospectively compared the perioperative data of and functional results in 15 patients having sternotomy (group I) with those of 15 patients having a videoendoscopic approach (group II).

RESULTS

The 30-day mortality was 2 patients in group I and 1 patient in group II. Mean duration of chest tube drainage was 8.7 +/- 1.8 days and 8.0 +/- 1.9 days and mean hospital stay, 12.3 +/- 1.9 and 12.5 +/- 2.1 days in groups I and II, respectively. Work of breathing decreased from 1.89 +/- 0.33 J/L and 1.76 +/- 0.22 J/L preoperatively to 0.75 +/- 0.06 J/L and 0.8 +/- 0.06 J/L (p < 0.01 and p < 0.05, respectively) after 3 months; and intrinsic positive end-expiratory pressure decreased from 7.15 +/- 1.31 cm H2O and 6.24 +/- 1.33 cm H2O to preoperatively 0.79 +/- 0.46 cm H2O and 1.13 +/- 0.44 cm H2O (p < 0.005 and p < 0.01, respectively) after 3 months in groups I and II, respectively. Forced expiratory volume in 1 second increased from preoperative values of 21.6% +/- 2.9% and 25.3% +/- 2.4% of predicted to 34.5% +/- 5.0% and 40.9% +/- 7.5% of predicted after 3 months (p < 0.05 in both groups) in groups I and II, respectively.

CONCLUSIONS

Both surgical approaches resulted in similar substantial improvement in lung function and physical fitness. The incidence of air leakage, the duration of chest tube drainage, and the hospital stay were the same for both procedures.

Recent advances in surgery for emphysema

Volume reduction surgery is based on the removal of volume-occupying but nonfunctioning emphysematous lung, which is thought to improve pulmonary elastic recoil. The reduction in thoracic volume may also improve thoracic cage and inspiratory muscle function. In addition, dyspnea is lessened, exercise tolerance is increased, and measured pulmonary function is improved. Alveolar gas exchange may also be improved. Selection criteria include marked airway obstruction secondary to emphysema, marked hyperinflation of the chest wall, and regional heterogeneity in the distribution of the emphysema. The best results are obtained with a bilateral procedure utilizing stapling resection. The two surgical approaches are median sternotomy and video-assisted thoracic surgery.

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.

Bilateral lung volume reduction surgery for advanced emphysema. A comparison of median sternotomy and thoracoscopic approaches

STUDY OBJECTIVES

To compare short-term outcomes following bilateral lung volume reduction surgery performed by median sternotomy (MS) and video-assisted thoracoscopic surgery (VATS).

METHODS

Bilateral lung volume reduction surgery was performed by MS in 80 patients and by VATS in 40. All patients underwent preoperative assessment with pulmonary function testing, arterial blood gas determination, and 6-min walk test (6MWT). Pulmonary function testing and 6MWT were repeated at 3 to 6 months postoperatively.

RESULTS

The mean age of the VATS group was lower than that of the MS group (59.3 +/- 9.4 vs 62.4 +/- 6.9 years; p = 0.001), but there were no differences in baseline functional parameters of disease severity (FEV1, FVC, residual volume [RV], arterial PCO2, or 6MWT). All patients in both groups were extubated at the completion of surgery, but 17.5% of patients in the MS group and 2.5% in the VATS group (p = 0.02) subsequently required reintubation at some point during the postoperative course. Thirty-day operative mortality was 4.2% for the MS group and 2.5% for the VATS group (p = not significant). However, total in-hospital mortality was 13.8% for the MS group, while it remained 2.5% for the VATS group (p = 0.05). Mortality was largely confined to patients 65 years of age or older. There was no significant difference in duration of air leaks or length of hospital stay between the two groups. Functional outcomes achieved with the two techniques were similar. Specifically, there was no difference between the two groups in mean postoperative FEV1, FVC, RV, or 6MWT, or in the magnitude of change in these parameters over preoperative values.

CONCLUSIONS

Bilateral lung volume reduction surgery performed by either MS and VATS approaches leads to similar improvements in pulmonary function and exercise tolerance. VATS is associated with a significantly lower incidence of respiratory failure and a trend toward decreased in-hospital mortality and may be the preferred technique, particularly for high-risk patients.

Results of 150 consecutive bilateral lung volume reduction procedures in patients with severe emphysema

Between January 1993 and February 1996, we performed 150 bilateral lung volume reduction procedures for patients with severe emphysema. Patients were selected on the basis of severe dyspnea, increased lung capacity, and a pattern of emphysema that included regions of severe destruction, hyperinflation, and poor perfusion. Twenty percent to 30% of the volume of each lung was excised with the use of a linear stapler and bovine pericardial strips attached to buttress the staple line. Patients were between 36 and 77 years old, with an average 1-second forced expiratory volume of 25% of predicted, total lung capacity of 142% of predicted, and residual volume of 283% of predicted. Ninety-three percent of patients required supplemental oxygen, continuously or with exertion. All patients but one were extubated at the end of the procedure. The 90-day mortality was 4%. Hospital stay progressively decreased with experience, and for the last 50 patients the median hospital stay was 7 days. Prolonged air leakage was the major complication. Results at 6 months show a 51% increase in the 1-second forced expiratory volume and a 28% reduction in the residual volume. The Pao2 increased by an average of 8 mm Hg, and 70% of the patients who had previously required continuous supplemental oxygen no longer had this requirement. The improvements in measured pulmonary function were paralleled by a significant reduction in dyspnea and an improvement in the quality of life. Reevaluation at 1 year and 2 years after operation showed the benefit to be well maintained. We conclude that lung volume reduction offers benefits not achievable by any means other than lung transplantation for highly selected patients with severe emphysema.

A surgical approach to treating emphysema: lung volume reduction surgery

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in Americans. In addition, COPD significantly affects the quality of life of afflicted patients. Historically, the treatment for emphysema has been primarily medical and includes medications, smoking cessation, and pulmonary rehabilitation. Recently a surgical procedure, lung volume reduction surgery (LVRS) has been reintroduced as a treatment for end-stage lung disease, primarily emphysema. In LVRS, wedge resections are performed to reduce the size of the lungs and improve alveolar functioning. This article describes the evaluation of patients who undergo LVRS and the associated pathophysiology in addition to the surgical procedure, inclusion and exclusion criteria, pre- and postoperative care, potential complications, and preliminary data associated with the procedure at one facility. Although LVRS is not a procedure for all patients with emphysema, it may significantly improve the quality of life of selected patients.

Role of lung reduction in lung transplant candidates with pulmonary emphysema

BACKGROUND

The average waiting time for candidates for lung transplantation (LTx) with end-stage emphysema is 21 months with a 15% mortality. We hypothesized that lung reduction might offer an alternative to LTx.

METHODS

Of 95 patients with end-stage emphysema evaluated by our LTx program, 45 were accepted for both lung reduction and LTx and 35 underwent lung reduction.

RESULTS

All 35 patients survived lung reduction. Thirty patients had a follow-up of 3 months. There was a significant improvement (p < 0.05) of forced expiratory volume in 1 second (0.64 to 0.97 L), forced vital capacity (2.12 to 2.76 L), residual volume (5.62 to 4.26 L), maximum voluntary ventilation (28.1 to 38.5 L/min), 6-minute walk (904 to 1,012 feet), Borg dyspnea index (3.7 to 2.4), and arterial carbon dioxide tension (44.9 to 41.6 mm Hg). Twenty patients (66%) were removed from the LTx list due to their significant improvement (group A). Compared with the remaining 10 patients with 3 months of follow-up (group B), percent increase in forced expiratory volume in 1 second (70% in group A versus 27% in group B) and in forced vital capacity (41% group A versus 18% group B) and percent decrease in residual volume (26% group A versus 1.5% group B) were significantly better in group A (p < 0.01). Seven patients in group B were bridged to LTx; 6 of these patients (86%) had hypercarbia before lung reduction compared with 8 (40%) in group A (p < 0.05). All are alive after LTx: the forced expiratory volume in 1 second is 53% and the forced vital capacity is 64% of predicted.

CONCLUSIONS

Lung reduction is safe and effective in selected LTx candidates with end-stage emphysema and has the potential to provide an alternative to LTx. Long-term follow-up is warranted to confirm these results.

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.

Clinical experimentation. Lessons from lung volume reduction surgery

Although the advancement of medical science can occur only with the systematic evaluation of new interventions, novel therapies continue to be introduced and accepted prior to thorough study. The recent development of lung volume reduction surgery for emphysema provides an illustration of the unwillingness or the inability of the medical community, unconstrained by legal or reimbursement limitations, to assure the safety and efficacy of a new procedure prior to widespread utilization. Medical practitioners must learn to recognize the experimental nature of new procedures independent of the courts and third-party payers. The nature of the informed consent that must be obtained for an experimental therapy is different from that which is required for standard medical practice and this difference can provide a test of whether a new treatment is experimental. A comparison between the introduction of lung volume reduction surgery and the rigorous scrutiny required of any pharmacologic interventions for emphysema underscores the double standard that exists for evaluating new surgical (and some medical) innovations. Such a double standard cannot be defended on ethical or scientific grounds. Specific changes in the way experimental therapies are introduced and disseminated are suggested. Until all new medical and surgical interventions are required to undergo a thorough evaluation prior to becoming standard of case, the promise of evidence-based medicine can never be fulfilled.

Lung reduction surgery in chronic obstructive lung disease

In the 1960s the promise of the Brantigan lung reduction surgery was shattered when it was shown that the improvement in airway conductance drifted back towards the preoperative value over a period of 12 to 18 months. Since then there has been a marked improvement in our understanding of emphysema, its pathology, and techniques for obtaining images of the lung. In addition, reliable automated cardiopulmonary and physiologic testing, advances in critical care medicine, and new pharmacologic agents have improved patient care. Surgical techniques now allow better control of air leaks and access to anatomic regions not previously accessible. The combination of all of the above makes lung reduction surgery worth re-examining as a palliative procedure for severely symptomatic patients. Clearly, it is not a panacea but can in some cases produce dramatic improvements in symptomatology and quality of life. This article presents the available data describing potential mechanisms of improvement and clinical outcomes following lung reduction surgery. It also outlines areas that need further work, such as patient selection and surgical techniques.