title: Dose minimization study of single-dose epidural morphine in patients undergoing hip surgery under regional anesthesia with bupivacaine.
abstract: BACKGROUND
  In order to decrease the rate of adverse effects, we aimed to identify the lowest analgesic dose of epidural morphine administered to patients undergoing hip surgery.
  
  
  METHODS
  Forty-five ASA I-II children undergoing surgical correction of hip dysplasia under caudal or epidural anesthesia with bupivacaine were randomized to receive epidural morphine 11.2, 15 or 20 microg.kg(-1) (groups 1, 2 and 3, respectively; 15 patients per group) immediately after completion of surgery. Postoperative pain control, sedation, motor block, urinary retention, pruritus and vomiting were evaluated.
  
  
  RESULTS
  In the recovery room, 46.7% of patients from group 1, 33.3% from group 2, and 93.3% from group 3 were sleeping but were easy to arouse (x(2) = 12.2; P < 0.005). The rest of the patients from each respective group were completely asleep. The cardiovascular and respiratory parameters were within normal limits. The ability to move the legs returned approximately 1 h after surgery in all three groups. Seven patients (46.7%) from group 1, nine (60%) from group 2, and 13 patients (86.7%) from group 3 vomited (x(2) = 5.4; P = 0.06). One patient receiving 20 microg.kg(-1) morphine experienced urinary retention. One patient receiving 15 microg.kg(-1) morphine suffered from pruritus. The duration of analgesia was similar, 12-14 h, in all three groups.
  
  
  CONCLUSIONS
  In patients undergoing hip surgery under regional anesthesia with bupivacaine, epidural morphine at a dose of 11.2 microg.kg(-1) administered immediately after completion of the procedure resulted in adequate pain relief for more than 12 h. Explanation of the high rate of patients vomiting (>45%) remains to be elucidated.
authors.affiliation: Department of Anaesthesia and Respiratory Therapy, Hospital Infantil de Mèxico Federico Gómez, México DF. caszam2002@yahoo.com.mx
authors.forename: Carlos
authors.initials: C
authors.lastname: Castillo-Zamora
authors.forename: Luz Antonia
authors.initials: LA
authors.lastname: Castillo-Peralta
authors.forename: Alejandro A
authors.initials: AA
authors.lastname: Nava-Ocampo
mesh_terms: D000293:Adolescent; D015360:Analgesia, Epidural; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000627:therapeutic use*; D000762:Anesthesia Recovery Period; D000765:Anesthesia, Conduction; D000779:Anesthetics, Local; D002045:Bupivacaine; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006801:Humans; D007223:Infant; D008297:Male; D016343:Monitoring, Intraoperative; D009020:Morphine / Q000008:administration & dosage* / Q000627:therapeutic use*; D019637:Orthopedic Procedures; D010149:Postoperative Pain / Q000188:drug therapy* / Q000453:epidemiology; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology / Q000517:prevention & control; D011537:Pruritus / Q000453:epidemiology / Q000517:prevention & control; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D002045:Bupivacaine