title: Alpha-2 adrenoceptor agonists as adjuncts to peripheral nerve blocks in children: a meta-analysis.
abstract: BACKGROUND
  Adult meta-analyses have verified that adjunct use of alpha-2 adrenoceptor agonists (A2AA) together with local anesthetics (LA) will prolong the duration of peripheral nerve blocks. The standard use of A2AAs for peripheral nerve blockade has recently been recommended also in children, but the evidence base in support of this suggestion has to date been equivocal. The purpose of this meta-analysis was to produce evidence-based data regarding the effect in children.
  
  
  METHODS
  Following a thorough literature search, five randomized controlled trials were included in a meta-analysis. Raw data from all studies were gathered and aggregated into patients randomized to receive plain LA (Group PLA) or LA mixed with either adjunct clonidine or dexmedetomidine (Group ADJ). The main outcome parameter was block duration (time to first administration of supplemental analgesic based on predetermined pain scores) analyzed by survival statistics. The total number of supplemental analgesic doses during the first 24 postoperative hours and serious side effects were included as secondary outcomes.
  
  
  RESULTS
  Pooling of the study data generated 141 patients in Group PLA and 142 patients in Group ADJ (overall n = 283; age: 0.8-13 years; weight 8-47 kg). Block duration was significantly prolonged (9.75 h vs 3.75 h) compared to the use of plain LA. Survival statistics verified a beneficial effect of using adjunct A2AAs [the log rank (Mantel-Cox) test (P = 0.0078), Gehan-Breslow-Wilcoxon test (P = 0.0027), and hazard ratio (1.653; 95% CI: 1.142 to 2.395)]. The number of patients that needed ≥ 2 doses of supplemental analgesics was higher in Group PLA (n = 19) compared to Group ADJ (n = 6) (P = 0.0088). No serious side effects were reported.
  
  
  CONCLUSIONS
  This meta-analysis provides evidence-based support for the use of adjunct alpha-2 adrenoceptor agonists when performing peripheral nerve blocks in children.
authors.affiliation: Department of Paediatric Anaesthesia & Intensive Care, Karolinska University Hospital, Stockholm, Sweden.|Department of Physiology & Pharmacology, Section of Anaesthesiology & Intensive Care, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Märit
authors.initials: M
authors.lastname: Lundblad
authors.affiliation: Faculty of Medicine, Department of Anaesthesia and Intensive Care, Children Hospital Bechir Hamza, University of Tunis El Manar, Tunis, Tunisia.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Trifa
authors.affiliation: Faculty of Medicine, Department of Anaesthesia and Intensive Care, Kassab Orthopedic Institute, University of Tunis El Manar, Tunis, Tunisia.
authors.forename: Olfa
authors.initials: O
authors.lastname: Kaabachi
authors.affiliation: Faculty of Medicine, Department of Anaesthesia and Intensive Care, Children Hospital Bechir Hamza, University of Tunis El Manar, Tunis, Tunisia.
authors.forename: Sonia
authors.initials: S
authors.lastname: Ben Khalifa
authors.affiliation: Faculty of Medicine, Department of Anaesthesia and Intensive Care, Children Hospital Bechir Hamza, University of Tunis El Manar, Tunis, Tunisia.
authors.forename: Amjed
authors.initials: A
authors.lastname: Fekih Hassen
authors.affiliation: Department of Anaesthesia, Royal Aberdeen Children's Hospital, Aberdeen, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Engelhardt
authors.affiliation: Childhood Cancer Research Unit Q6:05, Department of Women's and Children's Health, Karolinska Institutet, Astrid Lindgren Children's Hospital, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: Staffan
authors.initials: S
authors.lastname: Eksborg
authors.affiliation: Department of Paediatric Anaesthesia & Intensive Care, Karolinska University Hospital, Stockholm, Sweden.|Department of Physiology & Pharmacology, Section of Anaesthesiology & Intensive Care, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Per-Arne
authors.initials: PA
authors.lastname: Lönnqvist
mesh_terms: D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004359:Drug Therapy, Combination; D006801:Humans; D007223:Infant; D009407:Nerve Block / Q000379:methods*; D010525:Peripheral Nerves / Q000187:drug effects*; D016032:Randomized Controlled Trials as Topic; D013997:Time Factors
chemical_list: D000316:Adrenergic alpha-Agonists; D000779:Anesthetics, Local
keywords: adrenergic alpha-2 receptor agonists; child; local anesthetics; nerve block