Influences of spinal anesthesia on exercise tolerance in patients with chronic obstructive pulmonary disease.

Rationale: Lower limb muscle dysfunction contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We hypothesized that signaling from lower limb muscle group III/IV sensory afferents to the central motor command could be involved in premature cycling exercise termination in COPD.Objectives: To evaluate the effects of spinal anesthesia, which presumably inhibited central feedback from the lower limb muscle group III/IV sensory afferents on exercise tolerance and cardiorespiratory response during constant work-rate cycling exercise in patients with COPD.Methods: In a crossover and double-blind randomized design, eight patients with COPD (FEV1, 67 ± 8% predicted) completed a constant work-rate cycling exercise after sham (NaCl, interspinous L3–L4) or active (fentanyl 25 μg, intrathecal L3–L4) spinal anesthesia.Measurements and Main Results: When compared with placebo, endurance time was significantly prolonged after spinal anesthesia with fentanyl (639 ± 87 s vs. 423 ± 38 s [mean ...