THORACOSCOPIC LUNG-VOLUME REDUCTION SURGERY REDUCES DYSPNEA AND IMPROVES EXERCISE CAPACITY IN PATIENTS WITH EMPHYSEMA

Improved ventilation and exercise capacity follows thoracoscopic lung volume reduction surgery (TLVRS) in patients with severe emphysema. Th is improvement could be related to changes in inspiratory and expirato ry flows following surgery, with consequent improvement in dyspnea ind ices. Changes in inspiratory/expiratory flows at rest and exercise and their relation to subjective improvement in dyspnea after TLVRS are n ot well known, WE: studied 25 patients with severe emphysema who under went unilateral TLVRS performed in well-defined zones with decreased p erfusion in nuclear medicine lung scans, Early follow-up after surgery (4.2 +/- 0.8 mo) showed significant improvements in exercise toleranc e: The distance covered over a 6 min walk test increased from 934 +/- 297 to 1,071 +/- 241 ft (p = 0.01). Exercise tolerance using a bicycle ergometer showed increased exercise endurance from 4.43 +/- 1.7 to 5. 71 +/- 1.8 min (p < 0.001), The maximum workload tolerated increased f rom 37 +/- 19 to 52 +/- 21 W (p < 0.01) and VO2 max changed from 9.7 /- 2 to 11.8 +/- 3 (ml-kg)/min (p < 0.01). This increment was achieved by generating significantly larger minute ventilation ((V) over dot E ), from 24 +/- 11 to 29 +/- 10 L/min, reached through larger tidal vol umes (increasing from 951 +/- 330 to 1,145 +/- 367 ml), while maintain ing the same maximum respiratory rates. increased (V) over dot E was a lso accompanied by significant increases in both average inspiratory a nd expiratory flows measured during exercise: from 0.89 +/- 0.41 L/s t o 1.06 +/- 0.08 L/s, and from 0.77 +/- 0.37 to 0.90 +/- 0.32 L/s respe ctively (p < 0.01), The parallel increment in flows resulted in consta nt Ti/Ttot relationship, These functional changes correlated with incr eased inspiratory flows at rest: measured with pulmonary function test s (forced inspiratory volume in one s [FIV1], expiratory flows [FVC, F EV1], and increased maximum voluntary ventilation [MVV]) following the surgically induced reduction in residual volume (RV). These objective changes occurred parallel to improved dyspnea indices. The Baseline F ocal Score was 3.36 +/- 1.47 and the Transition Focal Score was 6.12 /- 0.7. The objectively measured variables at pest that best correlate d with subjective improvement in dyspnea were the change in MVV change in resting arterial Pa-O2, and change in FEV1 following TLVRS. Exerci se variables did not have significant correlation with subjective mark ers indicating improvement in dyspnea, with the exception of the chang e in Dyspneic Index [((V) over dot E/MVV)100] at maximum exercise.