Placement of a one-way valve in the segmental bronchi of the most diseased lobes has been used to prevent air from entering these portions of the lung during inspiration while still allowing air to exit, the authors explain.
Dr. Harvey O. Coxson from Vancouver General Hospital in British Columbia and colleagues correlated clinical outcome measures with lobar lung volume changes in 57 patients with severe upper-lobe predominant emphysema treated with one-way bronchial valves.
The only clinically meaningful changes after bronchial valve treatment were improvements in health-related quality of life and a trend for improvement in the 6-minute walk test distance.
CT showed moderate or complete lobar atelectasis in 12 patients (21%) at some point in the 6 months after the valve implantation treatment, the authors report.
Although total lung volume, mass or density showed no change, there were significant decreases in volume in the treated upper lobes and significant increases in volume in the untreated lobes in other areas.
The health-related quality of life improvements correlated with the increases in the non-upper lobe volume and with the interlobar volume shift, the report indicates.
The investigators propose "that the most common mechanism of action of bilateral bronchial valve treatment in severe upper-lobe predominant emphysema is not total lung volume reduction but a redirection, an interlobar shift, of inspired air to less diseased lung tissue."
Eur Respir J 2008;32:1443-1450.
Source : http://www.medscape.com/viewarticle/585935
No comments:
Post a Comment