title: Lower-Dose Mepivacaine Plus Fentanyl May Improve Spinal Anesthesia for Knee Arthroscopy.
abstract: BACKGROUND
  Previous work indicates that 30 mg isobaric mepivacaine 1.5% plus 10 μg fentanyl produces reliable anesthesia for knee arthroscopy with a more rapid recovery profile than 45 mg mepivacaine.
  
  
  OBJECTIVE
  This randomized controlled trial compared plain mepivacaine to three reduced doses of mepivacaine with 10 μg fentanyl for spinal anesthesia.
  
  
  METHODS
  Following written informed consent, subjects undergoing outpatient knee arthroscopy were prospectively randomized into one of four groups: mepivacaine 37.5 mg (M37.5); mepivacaine 30 mg plus fentanyl 10 μg (M30/F10); mepivacaine 27 mg plus fentanyl 10 μg (M27/F10); and mepivacaine 24 mg plus fentanyl 10 μg (M24/F10). The spinal was evaluated by the blinded anesthetist and surgeon. In the post-anesthesia care unit, sensory and motor block resolution was assessed. Subjects rated their satisfaction with the overall experience.
  
  
  RESULTS
  Group M30/F10 (n = 6) had two "fair" anesthetics, and group M27/F10 (n = 10) had one "fair" and one "inadequate" anesthetic. Both groups were eliminated from further enrollment per study protocol. The recovery profiles showed little difference between groups M37.5 and M30/F10, except for motor block resolution (median (25th percentile, 75th percentile): 171 (135, 195) and 128 (120, 135), respectively). Groups M27/F10 and M24/F10 demonstrated recovery profiles that were faster than group M37.5. Patient satisfaction was 10/10 for all groups.
  
  
  CONCLUSIONS
  Adding fentanyl 10 μg to a lower dose of mepivacaine 1.5% can lead to quicker recovery profiles. However, this advantage of a quicker recovery must be weighed against the likelihood of an incomplete anesthetic.
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Kahn
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Bae
authors.affiliation: Healthcare Research Institute, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Kara
authors.initials: K
authors.lastname: Fields
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: John G
authors.initials: JG
authors.lastname: Muller
authors.affiliation: Department of Orthopedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: John D
authors.initials: JD
authors.lastname: MacGillivray
authors.affiliation: Department of Orthopedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Howard A
authors.initials: HA
authors.lastname: Rose
authors.affiliation: Department of Orthopedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Riley J
authors.initials: RJ
authors.lastname: Williams
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Jacques T
authors.initials: JT
authors.lastname: YaDeau
keywords: arthroscopy; fentanyl; mepivacaine; spinal anesthesia