Double-blind randomized placebo-controlled trial of the effect of ketamine on postoperative morphine consumption in children following appendicectomy.
BACKGROUND
Ketamine has an opioid sparing effect following surgery in adults. This study investigated whether a similar effect is seen following appendicectomy in paediatric patients.


METHODS
Seventy-five ASA 1 or 2 children aged 7-16 years were recruited, and randomly allocated to one of three groups. Following a standard anaesthetic for appendicectomy, all were prescribed patient controlled analgesia (PCA) morphine with paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDS) as required for postoperative analgesia. In addition the control group received a saline infusion postoperatively, the ketamine bolus group received 500 micro g.kg-1 intravenous (i.v.) ketamine preincision and a saline infusion postoperatively, and the ketamine infusion group received 500 micro g.kg-1 i.v. ketamine preincision and a ketamine infusion at 4 micro g.kg-1 min-1 postoperatively. Morphine consumption, rescue analgesia requirement and side-effects were recorded postoperatively.


RESULTS
There was no difference in morphine consumption between the groups. The ketamine infusion group required more doses of rescue analgesia and reported more side-effects than the control group. Five patients, all in the ketamine infusion group, reported hallucinations.


CONCLUSIONS
In this paediatric population intravenous ketamine did not have a morphine sparing effect. The increased incidence of side-effects, especially hallucinations, reported by patients given a ketamine infusion may limit the further use of postoperative ketamine in children.
Dix
P
P
Department of Anaesthesia, RD & E Hospital (W), Exeter, UK. philippa@dixracwil.demon.co.uk
Martindale
S
S
Stoddart
P A
PA
D000293:Adolescent; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001062:Appendectomy; D002648:Child; D004311:Double-Blind Method; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000188:drug therapy* / Q000453:epidemiology; D016896:Treatment Outcome
D000701:Analgesics, Opioid; D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine; D009020:Morphine