title: Intraoperative loading attenuates nausea and vomiting of tramadol patient-controlled analgesia.
abstract: OBJECTIVE
  To evaluate the adverse effect profile of tramadol by patient-controlled analgesia (PCA) with administration of the loading dose either intraoperatively or postoperatively.
  
  
  METHODS
  Sixty adult patients scheduled for elective abdominal surgery were enrolled into this prospective, randomized, double blind study. The patients were anesthetized in a similar manner. At the beginning of wound closure, the patients were randomly allocated to receive 5 mg x kg(-1) tramadol (Group 1) or normal saline (Group 2). In the post-anesthesia care unit (PACU), when patients in either group complained of pain, 30 mg x ml(-1) tramadol i.v. were given every three minutes until visual analogue scale (VAS) 3, followed by tramadol PCA with bolus dose of 30 mg and five minute lockout interval. Pain control and adverse effect assessments were done in the PACU and every six hours for 48 hr post drug by an independent observer.
  
  
  RESULTS
  The loading dose was 290 +/- 45 mg in Group 1 and 315 +/- 148 mg in Group 2. In PACU, more nausea/vomiting both in terms of incidence (13/30, 43% vs 2/30, 6.6%, P < 0.05) and severity (nausea/vomiting score 2.5 +/- 2.0 vs 0.2 +/- 0.6, P < 0.05) was observed in patients with postoperative loading than in those with intraoperative loading of tramadol.
  
  
  CONCLUSIONS
  Administering the loading dose of tramadol during surgery decreases the nausea/vomiting associated with high dose of tramadol and improves the quality of tramadol PCA in the relief of postoperative pain.
authors.affiliation: Department of Anesthesia, Show-Chwan Memorial Hospital, Changhua, Taiwan, ROC. eddie@show.org.tw
authors.forename: W W
authors.initials: WW
authors.lastname: Pang
authors.forename: M S
authors.initials: MS
authors.lastname: Mok
authors.forename: S
authors.initials: S
authors.lastname: Huang
authors.forename: C P
authors.initials: CP
authors.lastname: Hung
authors.forename: M H
authors.initials: MH
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D016058:Analgesia, Patient-Controlled / Q000009:adverse effects*; D000701:Analgesics, Opioid / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy*; D020250:Postoperative Nausea and Vomiting / Q000517:prevention & control*; D011446:Prospective Studies; D014147:Tramadol / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol