title: Supplementation of retrobulbar block with clonidine in vitreoretinal surgery: effect on postoperative pain.
abstract: OBJECTIVE
  To evaluate the effect of clonidine when added to local anesthetics on duration of postoperative analgesia during retrobulbar block.
  
  
  METHODS
  Prospective, randomized controlled trial.
  
  
  METHODS
  Operating room and Postanesthesia Care Unit of a university-affiliated hospital.
  
  
  METHODS
  80 ASA physical status 1, 2, and 3 patients undergoing vitreoretinal surgery with or without scleral buckling.
  
  
  METHODS
  Patients in the control group (n = 40) received a retrobulbar block with 4.5 mL of lidocaine-bupivacaine and 0.5 mL of saline. Clonidine group patients (n = 40) received 4.5 mL of lidocaine-bupivacaine and 0.5 μg/kg of clonidine in a 0.5 mL volume.
  
  
  METHODS
  The time to first analgesic request, frequency of postoperative pain, and number of postoperative analgesic requests per patient were assessed.
  
  
  RESULTS
  37 patients in the control group (92.5%) versus 24 patients (60%) in the clonidine group reported pain postoperatively (P = 0.001), with a shorter time to first analgesic request noted in the control group (4.9 ± 3 vs 11.9 ± 5.3 hrs; P < 0.001). The median number of postoperative analgesic requests per patient during the first 24 hours was higher in the control group than the clonidine group [2 (0-3) vs. 1 (0-3); P < 0.001].
  
  
  CONCLUSIONS
  The addition of clonidine 0.5 μg/kg to the local anesthetics of a retrobulbar block for vitreoretinal surgery decreases the frequency of postoperative pain and prolongs the time of analgesia.
authors.affiliation: Department of Anesthesiology, Rizk Hospital, Beirut, Lebanon.
authors.forename: Vanda G
authors.initials: VG
authors.lastname: Yazbeck-Karam
authors.forename: Sahar M
authors.initials: SM
authors.lastname: Siddik-Sayyid
authors.forename: Elie L
authors.initials: EL
authors.lastname: Abi Nader
authors.forename: Daisy E
authors.initials: DE
authors.lastname: Barakat
authors.forename: Hoda S
authors.initials: HS
authors.lastname: Karam
authors.forename: Georges M
authors.initials: GM
authors.lastname: Cherfane
authors.forename: Jalal N Hajj
authors.initials: JN
authors.lastname: Hussein
authors.forename: Marie T
authors.initials: MT
authors.lastname: Aouad
mesh_terms: D000368:Aged; D019162:Anesthetics, Combined / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage; D002045:Bupivacaine / Q000008:administration & dosage; D003000:Clonidine / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008012:Lidocaine / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010149:Postoperative Pain / Q000517:prevention & control*; D011446:Prospective Studies; D013997:Time Factors; D057586:Vitreoretinal Surgery / Q000379:methods*
chemical_list: D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D008012:Lidocaine; D003000:Clonidine; D002045:Bupivacaine