title: A prospective comparison of ultrasound-guided and blindly placed radial arterial catheters.
abstract: BACKGROUND
  Arterial cannulation for continuous blood-pressure measurement and frequent arterial-blood sampling commonly are required in critically ill patients.
  
  
  OBJECTIVE
  To compare ultrasound (US)-guided versus traditional palpation placement of arterial lines for time to placement, number of attempts, sites used, and complications.
  
  
  METHODS
  This was a prospective, randomized interventional study at a Level 1 academic urban emergency department with an annual census of 78,000 patients. Patients were randomized to either palpation or US-guided groups. Inclusion criteria were any adult patient who required an arterial line according to the treating attending. Patients who had previous attempts at an arterial line during the visit, or who could not be randomized because of time constraints, were excluded. Enrollment was on a convenience basis, during hours worked by researchers over a six-month period. Patients in either group who had three failed attempts were rescued with the other technique for patient comfort. Statistical analysis included Fisher's exact, Mann-Whitney, and Student's t-tests.
  
  
  RESULTS
  Sixty patients were enrolled, with 30 patients randomized to each group. Patients randomized to the US group had a shorter time required for arterial line placement (107 vs. 314 seconds; difference, 207 seconds; p = 0.0004), fewer placement attempts (1.2 vs. 2.2; difference, 1; p = 0.001), and fewer sites required for successful line placement (1.1 vs. 1.6; difference, 0.5; p = 0.001), as compared with the palpation group.
  
  
  CONCLUSIONS
  In this study, US guidance for arterial cannulation was successful more frequently and it took less time to establish the arterial line as compared with the palpation method.
authors.affiliation: Section of Emergency Ultrasound, Department of Emergency Medicine, Medical College of Georgia, Augusta, GA, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Shiver
authors.forename: Michael
authors.initials: M
authors.lastname: Blaivas
authors.forename: Matthew
authors.initials: M
authors.lastname: Lyon
mesh_terms: D001794:Blood Pressure; D002406:Catheterization, Peripheral / Q000379:methods*; D004636:Emergency Service, Hospital; D006801:Humans; D010173:Palpation; D011446:Prospective Studies; D017534:Radial Artery / Q000000981:diagnostic imaging*; D014463:Ultrasonography