title: Intrathecal clonidine added to a bupivacaine-morphine spinal anesthetic improves postoperative analgesia for total knee arthroplasty.
abstract: Postoperative pain after total knee arthroplasty (TKA) is severe and can complicate early physical therapy. We tested the hypothesis that intrathecal clonidine would improve postoperative analgesia for TKA using a hyperbaric bupivacaine spinal anesthetic. In a double-blinded, placebo-controlled protocol, 81 ASA physical status I-III patients undergoing either a single or bilateral TKA were randomized into 4 groups with the following 2-mL solutions added to 15 mg of hyperbaric bupivacaine: 1) sterile saline, 2) morphine (250 microg), 3) morphine (250 microg) with clonidine (25 microg), and 4) morphine (250 microg) with clonidine (75 microg). At 1, 2, 4, 6, 12, and 24 h postoperatively, we measured visual analog scales (VAS), cumulative IV morphine consumption, hemodynamics, nausea, ancillary drugs, and side effects. Our primary comparison was between the clonidine with morphine groups versus the morphine group. We found that the combined administration of intrathecal clonidine and morphine decreased 24 h IV morphine consumption by 13 mg (P = 0.028) when compared with intrathecal morphine alone. This corresponded to a decrease in the VAS score of 1.3 cm at 24 h postoperatively (P = 0.047). Adverse side effects were similar among all groups with the exception of more relative hypotension in the clonidine groups through postoperative hour 6. We conclude that the coadministration of intrathecal clonidine and morphine decreases the 24-h IV morphine consumption and improves the 24-h VAS score when compared with intrathecal morphine alone.
  
  
  CONCLUSIONS
  In this prospective, randomized, double-blinded, and placebo-controlled trial, we identify an effective postoperative analgesic approach in total knee replacement surgery. Intrathecal morphine (250 microg) combined with clonidine (25 or 75 microg) provided superior analgesia compared with intrathecal morphine alone.
authors.affiliation: Departments of Anesthesiology, *Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; and †Central Vermont Medical Center, Berlin, Vermont.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Sites
authors.forename: Michael
authors.initials: M
authors.lastname: Beach
authors.forename: Russell
authors.initials: R
authors.lastname: Biggs
authors.forename: Christopher
authors.initials: C
authors.lastname: Rohan
authors.forename: Christopher
authors.initials: C
authors.lastname: Wiley
authors.forename: Athos
authors.initials: A
authors.lastname: Rassias
authors.forename: Janice
authors.initials: J
authors.lastname: Gregory
authors.forename: Gilbert
authors.initials: G
authors.lastname: Fanciullo
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000009:adverse effects; D000368:Aged; D016058:Analgesia, Patient-Controlled; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D000775:Anesthesia, Spinal / Q000009:adverse effects; D000779:Anesthetics, Local / Q000009:adverse effects; D019645:Arthroplasty, Replacement, Knee; D002045:Bupivacaine / Q000009:adverse effects; D003000:Clonidine / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy*; D011446:Prospective Studies
chemical_list: D000316:Adrenergic alpha-Agonists; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D003000:Clonidine; D002045:Bupivacaine