Treatment of chronic respiratory failure:: lung volume reduction surgery versus rehabilitation

Several treatment options are available for end-stage chronic obstructive pulmonary disease (COPD). Respiratory rehabilitation and lung volume reduction surgery are reviewed here. Respiratory rehabilitation can now be considered a prime treatment for COPD. Indeed, it has been clearly shown to improve exercise capacity and health status in these patients. Improvements in the former fell just below the minimal clinically important difference, whereas, those in the latter exceeded it. In addition, after a respiratory rehabilitation programme, a reduction in the number of hospital admissions and duration of each admission was demonstrated. It remains, however, difficult to predict accurately which patients will improve after rehabilitation and which will not. Factors that may contribute to this prediction are: baseline peak exercise ventilation/maximal voluntary ventilation, maximal inspiratory pressure, peripheral muscle force, and 6-min walking distance. Several studies have clearly shown that training effects are as pronounced in patients with severe as in those with moderate airflow obstruction. This is the most significant insight in this area of the 1990s. Lung volume reduction surgery may also be of benefit in patients with end-stage COPD. It is clear that lung function, exercise capacity and health status improve after this procedure, although the results of only six randomised studies are currently available. It remains difficult to accurately predict which patients will benefit from the procedure. From a model analysis, the most important action mechanism appears to be resizing of the lungs. Only in patients with an increased residual volume/total lung capacity ratio are beneficial effects expected. The model analysis, however, did not fit the experimental data very well in a recent publication. Emphysema heterogeneity is also likely to be related to the response. The question remains as to whether or not lung volume reduction surgery accelerates the decline in forced expiratory volume in one second in the long run. The technique is undergoing considerable progress as numerous new surgical and endoscopic procedures are currently being developed. The results of these procedures have not yet been systematically evaluated.