RT Journal Article SR Electronic T1 Invasive arterial blood pressure monitoring in an out-of-hospital setting: an observational study JF Emergency Medicine Journal JO Emerg Med J FD BMJ Publishing Group Ltd and the British Association for Accident & Emergency Medicine SP 210 OP 212 DO 10.1136/emj.2008.060608 VO 26 IS 3 A1 J Sende A1 P Jabre A1 B Leroux A1 C Penet A1 E Lecarpentier A1 M Khalid A1 A Margenet A1 J Marty A1 X Combes YR 2009 UL http://emj.bmj.com/content/26/3/210.abstract AB 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.Conclusion: 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.