title: Influences of spinal anesthesia on exercise tolerance in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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 (FEV(1), 67 ± 8% predicted) completed a constant work-rate cycling exercise after sham (NaCl, interspinous L(3)-L(4)) or active (fentanyl 25 μg, intrathecal L(3)-L(4)) spinal anesthesia.
  
  
  RESULTS
  When compared with placebo, endurance time was significantly prolonged after spinal anesthesia with fentanyl (639 ± 87 s vs. 423 ± 38 s [mean ± SEM]; P = 0.01). Ventilation and respiratory rate were reduced at isotime points under the fentanyl condition, whereas ventilatory efficiency and dead space ventilation were improved. Patients exhibited less dynamic hyperinflation at isotime points with spinal anesthesia. Consequently, the rise in dyspnea was significantly flatter during the fentanyl condition than with placebo.
  
  
  CONCLUSIONS
  Spinal anesthesia enhanced cycling exercise tolerance in patients with COPD, mostly by reducing ventilatory response and dyspnea during exercise; these effects were possibly mediated through the inhibition of group III/IV lower limb sensory muscle afferents.
authors: Institut Universitaire de Cardiologie et de Pneumologie de Québec, 2725 Chemin Ste-Foy, Québec, QC, Canada.
authors: Philippe
authors: P
authors: Gagnon
authors: Jean S
authors: JS
authors: Bussières
authors: Fernanda
authors: F
authors: Ribeiro
authors: Serge L
authors: SL
authors: Gagnon
authors: Didier
authors: D
authors: Saey
authors: Nathalie
authors: N
authors: Gagné
authors: Steeve
authors: S
authors: Provencher
authors: François
authors: F
authors: Maltais
mesh_terms: D000344:Afferent Pathways / Q000503:physiopathology; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000775:Anesthesia, Spinal; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects / Q000502:physiology*; D056228:Feedback, Sensory / Q000502:physiology; D005283:Fentanyl / Q000008:administration & dosage; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000187:drug effects / Q000503:physiopathology
chemical_list: D000701:Analgesics, Opioid; D005283:Fentanyl