title: Non-invasive continuous arterial pressure monitoring with Nexfin does not sufficiently replace invasive measurements in critically ill patients.
abstract: BACKGROUND
  In this study, we tested the reliability of a non-invasive finger-cuff-based continuous arterial blood pressure monitoring device (Nexfin, BMEYE, Amsterdam, NL) in critically ill surgical patients.
  
  
  METHODS
  Invasive intra-arterial and non-invasive arterial pressure measurements from 25 patients during a 4-h period were compared at five time points. Correlation and linear regression analysis were used and mean bias, precision [sd of bias] and limits of agreement (LOA) [bias (2.0 sd)] were calculated using the Bland-Altman method.
  
  
  RESULTS
  Eight data pairs were excluded because of error message from the non-invasive technique, and thus a total of 117 data pairs were analysed. Overall, correlation between mean arterial pressure (MAP) was r(2)=0.50. Bias, precision, and LOA between invasive and non-invasive MAP were 6 (12) and -18 to +30 mm Hg. In patients requiring norepinephrine (83 data pairs), correlation was r(2)=0.28 and bias, precision, and LOA were 6 (13) and -20 to +32 mm Hg, whereas in patients not receiving norepinephrine (34 data pairs) r(2) was 0.80 and mean bias, precision, and LOA were 6 (11) and -16 to +28 mm Hg. In patients with peripheral oedema (49 data pairs), r(2) was 0.40 and mean bias, precision and LOA were 7 (15) and -23 to +37 mm Hg. In patients without oedema (64 data pairs), r(2) was 0.66 and mean bias, precision, and LOA were 5 (9) and -13 to +23 mm Hg.
  
  
  CONCLUSIONS
  Non-invasive blood pressure monitoring with Nexfin does not seem to be sufficiently accurate to replace intra-arterial invasive blood pressure measurements in critically ill patients.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Witten/Herdecke, Hospital Merheim, Cologne, Germany. hohna@web.de
authors.forename: A
authors.initials: A
authors.lastname: Hohn
authors.forename: J M
authors.initials: JM
authors.lastname: Defosse
authors.forename: S
authors.initials: S
authors.lastname: Becker
authors.forename: C
authors.initials: C
authors.lastname: Steffen
authors.forename: F
authors.initials: F
authors.lastname: Wappler
authors.forename: S G
authors.initials: SG
authors.lastname: Sakka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D062186:Arterial Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation / Q000379:methods; D015924:Blood Pressure Monitors; D002406:Catheterization, Peripheral / Q000379:methods / Q000706:statistics & numerical data*; D016638:Critical Illness; D005260:Female; D005385:Fingers / Q000098:blood supply; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D055815:Young Adult
keywords: equipment-Finapres; intensive care; monitoring-arterial pressure