title: Invasive arterial blood pressure monitoring in an out-of-hospital setting: an observational study.
abstract: BACKGROUND
  Non-invasive arterial blood pressure measurement is often inaccurate in emergency unstable patients. A study was undertaken to assess the feasibility of out-of-hospital intra-arterial catheterisation in haemodynamically unstable patients and to evaluate the correlation between invasive and non-invasive arterial pressure values.
  
  
  METHODS
  In this prospective 2-year observational study conducted by mobile emergency medical units, the success rate of arterial catheterisation was calculated and blood pressure values measured invasively and non-invasively after successful catheterisation were compared.
  
  
  RESULTS
  94 patients were included. The success rate for catheterisation (44 radial access, 50 femoral access) was 86% (95% CI 79% to 93%). Bias and precision in invasive versus non-invasive comparisons were -0.1, 38 mm Hg for systolic pressure and 4.2, 27 mm Hg for diastolic pressure. Values differed by more than 20 mm Hg in over 40% of patients. Invasive measurement led to 79 changes in vasoactive treatment in 51 patients.
  
  
  CONCLUSIONS
  Emergency out-of-hospital invasive arterial blood pressure monitoring in haemodynamically unstable patients is highly feasible. Discrepancies between invasive and non-invasive measurements are common and highlight the value of early out-of-hospital monitoring.
authors.affiliation: Service d'Anesthésie Réanimation et SAMU 94, Henri Mondor University Hospital, Créteil, France.
authors.forename: J
authors.initials: J
authors.lastname: Sende
authors.forename: P
authors.initials: P
authors.lastname: Jabre
authors.forename: B
authors.initials: B
authors.lastname: Leroux
authors.forename: C
authors.initials: C
authors.lastname: Penet
authors.forename: E
authors.initials: E
authors.lastname: Lecarpentier
authors.forename: M
authors.initials: M
authors.lastname: Khalid
authors.forename: A
authors.initials: A
authors.lastname: Margenet
authors.forename: J
authors.initials: J
authors.lastname: Marty
authors.forename: X
authors.initials: X
authors.lastname: Combes
mesh_terms: D000368:Aged; D001795:Blood Pressure Determination / Q000379:methods*; D001930:Brain Injuries / Q000628:therapy; D002406:Catheterization, Peripheral / Q000379:methods*; D016009:Chi-Square Distribution; D004632:Emergency Medical Services / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006323:Heart Arrest / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D020521:Stroke / Q000628:therapy