Study objectives: We sought to investigate the effect
of lung volume reduction surgery (LVRS) on regional lung
Design: Retrospective analysis of
routinely acquired data before and after LVRS.
Setting: Large, urban, university medical center.
Patients: Twenty-nine patients with severe emphysema.
Intervention: Bilateral LVRS.
results:133Xe washout curves during lung
scintigraphy exhibit a biphasic pattern (the first component of the
washout curve [mr] corresponds to an initial rapid
phase in washout that reflects larger airways emptying, and the second
component [ms] reflects a slower phase of washout that is
attributed to gas elimination via smaller airways). We analyzed six
standardized regions of the lung (upper, mid, and lower zones of the
right and left lung), and calculated mr and ms
for each lung region. The mean (± SE) baseline FEV1 was
0.69 ± 0.04 L, total lung capacity (TLC) was 139 ± 4% predicted,
and the residual volume (RV)/TLC ratio was 65 ± 2%. The mean
improvement in FEV1 3 months post-LVRS was 38%. Post-LVRS,
mr and ms increased in 79 and 74 lung regions,
respectively, and there was no relationship with respect to lung
regions that had or had not been operated on. The increase in
ms, however, significantly correlated with the increase in
FEV1 (r = 0.66; p < 0.0001) and the
decrease in RV/TLC (r = −0.67; p < 0.0001). An
increase in ms also correlated with a decrease in
Paco2 (r = −0.39;
p = 0.03), but mr showed no relationship with any
Conclusions: Small airways ventilation in
lung regions that had and had not been operated on is associated with a
greater improvement in lung mechanics following