title: Use of sterile saline as a conduction agent for ultrasound visualization of central venous structures.
abstract: OBJECTIVE
  To determine whether sterile saline as a conduction agent provides adequate visualization of anatomic structures to attempt ultrasound-guided vascular access.
  
  
  METHODS
  This prospective study involved a convenience sample of adult patients (18 years and older) who presented to an urban academic ED during a 3-month study period. Each patient had three six-second ultrasound video clips obtained of the right internal jugular vein and surrounding structures utilizing three different conduction agents, water-based gel (the control), sterile saline or no conduction agent. Video clips were randomized and assigned a numeric code to blind reviewers to the conduction agent. They were then independently reviewed by two experts who determined whether anatomic structures were visualized with enough detail to perform ultrasound-guided vascular access. The reviewers also rated the overall image quality of each video clip using a 100 mm visual analogue scale (VAS).
  
  
  RESULTS
  Forty-seven patients were included in the final analysis. The raw agreement was 100% (95% confidence intervals [CI]: 93-100%) with a kappa of 1.0 between the two reviewers in assessing whether they would be able to perform vascular access using the images obtained using saline as a conduction agent. The median VAS for gel across both reviewers was 92 (95% CI: 90-93) and the median VAS differences for saline and no medium were -3 (95% CI: -1 to -3) and -46 (95% CI: -22 to -61), respectively.
  
  
  CONCLUSIONS
  The use of sterile saline as a conduction agent allows adequate visualization of anatomic structures to attempt ultrasound-guided vascular access.
authors.affiliation: Department of Emergency Medicine, Nelson Hospital, Nelson, New Zealand. ryan.windish@nmhs.govt.nz
authors.forename: Ryan
authors.initials: R
authors.lastname: Windish
authors.forename: Todd
authors.initials: T
authors.lastname: Ungar
authors.forename: Brandon
authors.initials: B
authors.lastname: Backlund
authors.forename: Jason S
authors.initials: JS
authors.lastname: Haukoos
authors.forename: John
authors.initials: J
authors.lastname: Kendall
mesh_terms: D000046:Academic Medical Centers; D000293:Adolescent; D000328:Adult; D001315:Australia; D002405:Catheterization, Central Venous; D003287:Contrast Media; D005260:Female; D006801:Humans; D007601:Jugular Veins / Q000000981:diagnostic imaging*; D008297:Male; D011446:Prospective Studies; D012965:Sodium Chloride; D018084:Ultrasonography, Interventional / Q000379:methods*; D019037:Urban Health Services; D014741:Video Recording
chemical_list: D003287:Contrast Media; D012965:Sodium Chloride