Lung volume reduction surgery does not improve diaphragmatic contractile properties or atrophy in hamsters with elastase-induced emphysema

II is claimed that lung volume reduction surgery (LVRS) improves inspirator y muscle function. As diaphragm structure and function are not directly app raisable in patients, we studied the effects of LVRS on the diaphragm in vi tro contractile properties and morphology in hamsters with elastase-induced emphysema. Four months after intratracheal instillation of elastase (40 U/ 100 g), hamsters underwent either bilateral LVRS (LVRS, n = 11) or a sham o peration (SHAM, n = 8). Four animals died during the perioperative period i n LVRS (n = 7). Hamsters instilled with saline served as control (CTL, n = 8). Animals were studied at the age of 9 mo. LVRS was associated with a sig nificant 25% decrease in functional residual capacity compared to SHAM (p < 0.05). Compared with CTL, LVRS and SHAM showed a significant 18% and 14% r eduction in diaphragm mass, respectively (p = 0.02). LVRS had a significant ly decreased twitch tension compared to CTL and SHAM (p < 0.01). Both LVRS and SHAM showed increased resistance to muscle fatigue compared with CTL. T he histochemical analysis revealed a significant shift from type IIx/b towa rd type IIa fibers in LVRS and SHAM compared with CTL. In conclusion, emphy sema is associated with functional adaptations but LVRS does not appear to beneficially alter the diaphragm contractile and morphological characterist ics in hamsters with elastase-induced emphysema.