title: Ondansetron given before induction of anesthesia reduces shivering after general anesthesia.
abstract: The neurotransmitter pathways involved in the mechanism of postanesthetic shivering (PAS) are poorly understood. Meperidine, clonidine, and physostigmine are all effective treatments, indicating that opioid, alpha(2)-adrenergic, and anticholinergic systems are probably involved. We investigated the effect of ondansetron, a 5-HT(3) antagonist used to treat postoperative nausea and vomiting, on intraoperative core and peripheral temperatures and PAS. Eighty-two patients (age, 18-60 yr) undergoing orthopedic, general, or urological surgery were randomized into three groups in this double-blinded, placebo-controlled, study: Group O4 (n = 27) received ondansetron 4 mg IV, Group O8 (n = 27) received ondansetron 8 mg IV, and Group C (n = 28) received saline IV immediately before the anesthetic induction. Core (tympanic) and fingertip temperature (dorsum of middle finger) were recorded. Anesthesia was induced with IV fentanyl 1 microg/kg and propofol 2.0-2.5 mg/kg and maintained with 1 minimum alveolar anesthetic concentration isoflurane in 70% nitrous oxide/oxygen. The occurrence of shivering was documented clinically during recovery by nursing staff, who were unaware of the group assignment. PAS occurred in 16 of 28 (57%) patients in Group C, compared with 9 of 27 (33%) in Group O4 (P = 0.13) and 4 of 27 (15%) patients in Group O8 (P = 0.003). Within each group, core temperature decreased and peripheral temperature increased significantly, but there were no significant differences among the groups at any time interval. We conclude that ondansetron 8 mg IV given during the induction of anesthesia prevents PAS without affecting the core-to-peripheral redistribution of heat during general anesthesia. This suggests that serotonergic pathways have a role in the regulation of PAS.
  
  
  CONCLUSIONS
  In a randomized, double-blinded, placebo-controlled, clinical study, ondansetron 8 mg IV, given just before the induction, reduced the incidence of postanesthetic shivering compared with saline. The anticipated core-to-peripheral redistribution of body temperature during general anesthesia was not affected. This implies that ondansetron probably acts by a central inhibitory mechanism, and that 5-hydroxytryptaminergic pathways have a role in regulating postanesthetic shivering.
authors.affiliation: University Department of Anaesthesia, Leicester University, Leicester, United Kingdom.
authors.forename: R M
authors.initials: RM
authors.lastname: Powell
authors.forename: D J
authors.initials: DJ
authors.lastname: Buggy
mesh_terms: D000328:Adult; D000768:Anesthesia, General / Q000009:adverse effects*; D000932:Antiemetics / Q000627:therapeutic use*; D001831:Body Temperature / Q000187:drug effects; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D017294:Ondansetron / Q000627:therapeutic use*; D012768:Shivering / Q000187:drug effects*; D012881:Skin Temperature / Q000187:drug effects
chemical_list: D000932:Antiemetics; D017294:Ondansetron