title: Randomized study of teaching ultrasound-guided vascular cannulation using a phantom and the freehand versus needle guide-assisted puncture techniques.
abstract: OBJECTIVE
  The task of ultrasound-guided vessel cannulation can be technically difficult. Needle guides have been designed to facilitate vessel puncture. We aimed to identify and compare the learning curves of participants performing vessel puncture with conventional freehand (FH) and needle guide-assisted (NG) techniques.
  
  
  METHODS
  Thirty-six participants were randomly allocated to either the FH or the NG group. They were asked to consecutively perform as many as 30 vessel punctures on a simulated phantom model. Quantitative metrics (time taken and number of skin and posterior-wall punctures) were recorded and compared between the two groups. The cumulative sum and moving F-test statistical methods were used to delineate the learning curves.
  
  
  RESULTS
  There was a significantly lower rate of posterior-wall punctures in the NG group than in the FH group (15% versus 26%; p < 0.0001). Participants in the NG group also performed significantly fewer skin punctures than did those in the FH group (mean, 405 versus 515; p < 0.0001). Cumulative sum statistical method analysis showed that participants in the NG group surmounted the learning curve earlier (13 attempts; interquartile range, 10.3-17.0) than did those in the FH group (19 attempts; interquartile range, 15.0-27.5). The number of attempts to surmount the learning curve was significantly less for the FH group (7.2 versus 16 attempts; p = 0.007) when using the moving F-test.
  
  
  CONCLUSIONS
  The NG puncture allows a greater number of trainees to cross the learning threshold and offers the advantages of fewer posterior-wall punctures and skin punctures. The use of NG puncture may result in a shorter path to proficiency, allowing trainees to attempt needle puncture earlier and with a greater degree of safety.
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London, W12 0HS, UK.
authors.forename: Usman
authors.initials: U
authors.lastname: Jaffer
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London, W12 0HS, UK.
authors.forename: Pasha
authors.initials: P
authors.lastname: Normahani
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London, W12 0HS, UK.
authors.forename: Prashant
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London, W12 0HS, UK.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Aslam
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London, W12 0HS, UK.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Standfield
mesh_terms: D002405:Catheterization, Central Venous / Q000379:methods*; D002983:Clinical Competence; D005260:Female; D006801:Humans; D008297:Male; D008348:Manikins; D009339:Needles; D019047:Phantoms, Imaging; D011677:Punctures; D018084:Ultrasonography, Interventional / Q000379:methods*; D006113:United Kingdom; D055815:Young Adult
keywords: education; learning curve; puncture; ultrasonography; vascular; venous access