title: Nonopioid additives to local anaesthetics for caudal blockade in children: a systematic review.
abstract: BACKGROUND
  Caudal epidural injection with local anaesthetics is a popular regional technique used in infants and children. A disadvantage of caudal blockade is the relatively short duration of postoperative analgesia. Opioids have traditionally been added to increase the duration of analgesia but have been associated with unacceptable side-effects. A number of nonopioid additives have been suggested to increase the duration of analgesia.
  
  
  METHODS
  A systematic review was conducted to identify randomized control trials comparing the use of local anaesthetic to local anaesthetic with nonopioid additives for caudal blockade in children. The increase in duration of analgesia and side-effects were compared.
  
  
  RESULTS
  The addition of clonidine to the local anaesthetic solution produces an increase in the duration of analgesia following caudal blockade in children (pooled weighted mean difference of 145 min with 95% confidence interval of 132-157 min). Side-effects include sedation and the potential for neonatal respiratory depression. Ketamine and midazolam further increase the duration of analgesia, however, the potential for neurotoxicity remains a concern.
  
  
  CONCLUSIONS
  The evidence examined shows an increased duration of analgesia with clonidine, ketamine and midazolam. However, we are not convinced that the routine use of these adjuvants in the setting of elective outpatient surgery shows improved patient outcome. It is unclear if the potential for neurotoxicity is outweighed by clinical benefits. Further testing, including large clinical trials, is required before recommending routine use of nonopioid additives for caudal blockade in children.
authors.affiliation: Department of Anesthesia, British Columbia's Children's Hospital, Vancouver, Canada. anserminos@yahoo.com
authors.forename: Mark
authors.initials: M
authors.lastname: Ansermino
authors.forename: Rahul
authors.initials: R
authors.lastname: Basu
authors.forename: Christine
authors.initials: C
authors.lastname: Vandebeek
authors.forename: Carolyne
authors.initials: C
authors.lastname: Montgomery
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000009:adverse effects / Q000627:therapeutic use*; D000763:Anesthesia, Caudal / Q000009:adverse effects / Q000379:methods*; D000779:Anesthetics, Local / Q000009:adverse effects / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D010149:Postoperative Pain / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data
chemical_list: D018712:Analgesics, Non-Narcotic; D000779:Anesthetics, Local