title: The learning process of the hydrolocalization technique performed during ultrasound-guided regional anesthesia.
abstract: BACKGROUND
  Because poor echogenicity of the needle remains a safety issue, we decided to analyze the learning process of the hydrolocalization technique (Hloc) performed to continuously identify needle-tip anatomical position during many ultrasound-guided regional anesthesia procedures.
  
  
  METHODS
  Ten senior anesthesiologists naïve to the Hloc agreed to participate in the study. They were requested to perform 40 out-of-plane (OOP) approach ultrasound-guided axillary blocks (AB) each using the Hloc. The Hloc, which is a needle-tip localization principle, was performed by means of repetitive injections of a small amount of a local anesthetic solution (0.5-1 ml) under an ultrasound beam. Details of the learning process and skill acquisition of the Hloc were derived from the following parameters: the duration of block placement, a measure of the perceived difficulty of needle-tip visualization, a measure of block placement difficulty, and the amount of local anesthetics solution required for the technique.
  
  
  RESULTS
  Four hundred ABs were performed. The success rate of an ultrasound-guided AB was 98%. The Hloc was successful in all patients. Skill acquisition over time of the Hloc was associated with a significant reduction of both the duration and the perceived difficulty of ABs placement. Apprenticeship data revealed that 20 blocks were required to successfully place AB within 5 min in most cases using the Hloc.
  
  
  CONCLUSIONS
  The Hloc performed during the OOP approach of ultrasound-guided regional anesthesia is a simple technique with a relatively short learning process feasible for efficient placement of ABs.
authors.affiliation: Claude Galien Private Hospital, Quincy-Sous-Sénart, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Bloc
authors.forename: L
authors.initials: L
authors.lastname: Mercadal
authors.forename: T
authors.initials: T
authors.lastname: Dessieux
authors.forename: T
authors.initials: T
authors.lastname: Garnier
authors.forename: J-P
authors.initials: JP
authors.lastname: Estebe
authors.forename: A
authors.initials: A
authors.lastname: Le Naoures
authors.forename: B
authors.initials: B
authors.lastname: Komly
authors.forename: P
authors.initials: P
authors.lastname: Leclerc
authors.forename: B
authors.initials: B
authors.lastname: Morel
authors.forename: C
authors.initials: C
authors.lastname: Ecoffey
authors.forename: G
authors.initials: G
authors.lastname: Dhonneur
mesh_terms: D000765:Anesthesia, Conduction / Q000295:instrumentation / Q000379:methods*; D000776:Anesthesiology / Q000193:education* / Q000295:instrumentation; D000779:Anesthetics, Local / Q000008:administration & dosage; D001365:Axilla; D001826:Body Fluids / Q000000981:diagnostic imaging*; D002983:Clinical Competence; D004558:Electric Stimulation; D006801:Humans; D007858:Learning; D009339:Needles; D009407:Nerve Block; D010525:Peripheral Nerves / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D000779:Anesthetics, Local