title: Effect of fentanyl and lidocaine on the end-tidal sevoflurane concentration preventing motor movement in dogs.
abstract: OBJECTIVE To determine effects of fentanyl, lidocaine, and a fentanyl-lidocaine combination on the minimum alveolar concentration of sevoflurane preventing motor movement (MACNM) in dogs. ANIMALS 6 adult Beagles. PROCEDURES Dogs were anesthetized with sevoflurane in oxygen 3 times (1-week intervals). Baseline MACNM(MACNM-B) was determined starting 45 minutes after induction of anesthesia. Dogs then received 1 of 3 treatments IV: fentanyl (loading dose, 15 μg/kg; constant rate infusion [CRI], 6 μg/kg/h), lidocaine (loading dose, 2 mg/kg; CRI, 6 mg/kg/h), and the fentanyl-lidocaine combination at the same doses. Determination of treatment MACNM(MACNM-T) was initiated 90 minutes after start of the CRI. Venous blood samples were collected at the time of each treatment MACNMmeasurement for determination of plasma concentrations of fentanyl and lidocaine. RESULTS Mean ± SEM overall MACNM-Bfor the 3 treatments was 2.70 ± 0.27 vol%. The MACNMdecreased from MACNM-Bto MACNM-Tby 39%, 21%, and 55% for fentanyl, lidocaine, and the fentanyl-lidocaine combination, respectively. This decrease differed significantly among treatments. Plasma fentanyl concentration was 3.25 and 2.94 ng/mL for fentanyl and the fentanyl-lidocaine combination, respectively. Plasma lidocaine concentration was 2,570 and 2,417 ng/mL for lidocaine and the fentanyl-lidocaine combination, respectively. Plasma fentanyl and lidocaine concentrations did not differ significantly between fentanyl and the fentanyl-lidocaine combination or between lidocaine and the fentanyl-lidocaine combination. CONCLUSIONS AND CLINICAL RELEVANCE CRIs of fentanyl, lidocaine, and the fentanyl-lidocaine combination at the doses used were associated with clinically important and significant decreases in the MACNMof sevoflurane in dogs.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Suarez
authors.forename: Reza
authors.initials: R
authors.lastname: Seddighi
authors.forename: Christine M
authors.initials: CM
authors.lastname: Egger
authors.forename: Barton W
authors.initials: BW
authors.lastname: Rohrbach
authors.forename: Sherry K
authors.initials: SK
authors.lastname: Cox
authors.forename: Butch K
authors.initials: BK
authors.lastname: KuKanich
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Doherty
mesh_terms: D018685:Anesthetics, Inhalation / Q000378:metabolism / Q000493:pharmacokinetics*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005283:Fentanyl / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D008012:Lidocaine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008738:Methyl Ethers / Q000378:metabolism / Q000493:pharmacokinetics*; D009043:Motor Activity / Q000187:drug effects; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D000077149:Sevoflurane; D008012:Lidocaine; D005283:Fentanyl