title: Ultrasound-guided tranversus abdominis plane block for herniorrhaphy in children: what is the optimal dose of levobupivacaine?
abstract: BACKGROUND
  Regional anaesthesic techniques are commonly used for the management of pain following lower abdominal surgery in children. The transversus abdominis plane (TAP) block has shown promise for perioperative analgesia, but data on the optimal dose regimen are limited.
  
  
  OBJECTIVE
  To evaluate the optimal dose of levobupivacaine for successful ultrasound-guided TAP block in children.
  
  
  METHODS
  A dose finding prospective study using Dixon's up-and-down sequential method.
  
  
  METHODS
  University Hospital Paediatric Anaesthesia Unit.
  
  
  METHODS
  Twenty-seven consecutive children aged 1 to 5 years scheduled for day-case elective herniorrhaphy.
  
  
  METHODS
  After standardised induction of general anaesthesia, ultrasound-guided TAP block was performed with a fixed volume of 0.2  ml  kg(-1) of levobupivacaine solution. The dose of levobupivacaine was determined by Dixon's up-and-down method starting from 0.5  mg  kg(-1)with an interval of 0.1 mg   kg(-1). Block failure was defined as a 20% increase in heart rate or mean arterial pressure from baseline. Rescue analgesia consisted of intravenous remifentanil infusion during surgery and intravenous nalbuphine in the postanaesthetic care unit (PACU). Patients were assessed using the FLACC (face, legs, activity, cry and consolability) pain scale, the rescue analgesic consumption in the PACU and day-case unit and the postoperative pain measure for parents score at home.
  
  
  METHODS
  The mean effective dose of levobupivacaine resulting in an effective TAP block in 50% of cases (ED50) obtained by using Dixon's up-and-down sequential method. The ED50 and ED95 were further estimated by bootstrapping.
  
  
  RESULTS
  The ED50 according to the up-and-down staircase method was 0.22  mg   kg(-1) [95% confidence interval (CI) 0.19 to 0.25]. Bootstrap replicates of the original dataset resulted in ED50 and ED95 estimates of 0.16  mg    kg(-1) (95% CI 0.11 to 0.24) and 0.43 mg  kg(-1)(95% CI 0.30 to 0.57), respectively.
  
  
  CONCLUSIONS
  As part of a multimodal analgesia strategy, ultrasound-guided TAP block with 0.2  ml  kg(-1)of 0.2% levobupivacaine provides successful peroperative analgesia in 95% of children who underwent herniorrhaphy.
authors.affiliation: From the Department of Anaesthesia and Critical Care Medicine, Lapeyronie University Hospital (CS, CM, AR, OR, SB, XC, CD), Department of Biostatistics, Epidemiology and Medical Information, La Colombière University Hospital (SB, NM), and Department of Abdominal and Urological Surgery, Lapeyronie University Hospital, Montpellier, France (NK).
authors.forename: Chrystelle
authors.initials: C
authors.lastname: Sola
authors.forename: Cecilia
authors.initials: C
authors.lastname: Menace
authors.forename: Alain
authors.initials: A
authors.lastname: Rochette
authors.forename: Olivier
authors.initials: O
authors.lastname: Raux
authors.forename: Sophie
authors.initials: S
authors.lastname: Bringuier
authors.forename: Nicolas
authors.initials: N
authors.lastname: Molinari
authors.forename: Nicolas
authors.initials: N
authors.lastname: Kalfa
authors.forename: Xavier
authors.initials: X
authors.lastname: Capdevila
authors.forename: Christophe
authors.initials: C
authors.lastname: Dadure
mesh_terms: D000005:Abdomen; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D002675:Child, Preschool; D005260:Female; D059685:Herniorrhaphy / Q000379:methods*; D006801:Humans; D007223:Infant; D000077554:Levobupivacaine; D008297:Male; D009407:Nerve Block / Q000379:methods*; D059408:Pain Management / Q000379:methods; D019990:Perioperative Care / Q000379:methods; D011446:Prospective Studies; D017211:Treatment Failure; D018084:Ultrasonography, Interventional
chemical_list: D000779:Anesthetics, Local; D000077554:Levobupivacaine; D002045:Bupivacaine