title: Effect of opioid administration on cardiorespiratory and muscle oxygenation during lifting in chronic back pain patients.
abstract: The objectives of this study were to examine the effects of opioid administration on the acute cardiorespiratory and muscle oxygenation responses during a repetitive lifting and lowering test (RLL) to voluntary fatigue in participants with chronic low back pain (LBP). Written informed consent was obtained from 27 LBP participants (mean age 50.9 +/- 16.4 years) who completed one testing session during which they were administered a saline placebo and opioid (1 microg/kg of fentanyl intravenously) in random order. The participants performed the RLL at a rate that they felt that they could sustain for an 8-h working day. Acute opioid administration increased the total lifting time and total work done during RLL by 35 and 48%, respectively (p < 0.05). However, the increased work capacity was accompanied by a significant (p < 0.05) increase in oxygen cost of 22% per unit amount of work done and significant (p < 0.05) increases in heart rate (7%) and ventilation rate (10%). Near infrared spectroscopic analysis of erector spinae oxygenation and blood volume responses during RLL indicated no significant (p > 0.05) differences between the opioid and placebo phases. These findings suggest that the increased energy cost of lifting as a result of opioid administration was due to enhanced central oxygen transport and not peripheral muscle oxygen extraction.
authors.affiliation: Department of Occupational Therapy, University of Alberta, Room 3-73, Corbett Hall, Edmonton, AB T6G 2G4, Canada. yagesh.bhambhani@ualberta.ca
authors.forename: Yagesh
authors.initials: Y
authors.lastname: Bhambhani
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Gross
authors.forename: Mark
authors.initials: M
authors.lastname: Haykowsky
authors.forename: Saifudin
authors.initials: S
authors.lastname: Rashiq
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000494:pharmacology / Q000627:therapeutic use*; D002153:Calorimetry, Indirect; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005283:Fentanyl / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D017770:Lifting / Q000009:adverse effects; D017116:Low Back Pain / Q000188:drug therapy* / Q000209:etiology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects*; D019265:Spectroscopy, Near-Infrared
chemical_list: D000701:Analgesics, Opioid; D005283:Fentanyl