title: Comparison of the non-invasive Nexfin® monitor with conventional methods for the measurement of arterial blood pressure in moderate risk orthopaedic surgery patients.
abstract: OBJECTIVE
  Continuous invasive arterial blood pressure (IBP) monitoring remains the gold standard for BP measurement, but traditional oscillometric non-invasive intermittent pressure (NIBP) measurement is used in most low-to-moderate risk procedures. This study compared non-invasive continuous arterial BP measurement using a Nexfin® monitor with NIBP and IBP monitors.
  
  
  METHODS
  This was a single-centre, prospective, pilot study in patients scheduled for elective orthopaedic surgery. Systolic BP, diastolic BP and mean arterial blood pressure (MAP) were measured by Nexfin®, IBP and NIBP at five intraoperative time-points. Pearson correlation coefficients, Bland-Altman plots and trending ability of Nexfin® measurements were used as criteria for success in the investigation of measurement reliability.
  
  
  RESULTS
  A total of 20 patients were enrolled in the study. For MAP, there was a sufficient correlation between IBP/Nexfin® (Pearson = 0.75), which was better than the correlation between IBP/NIBP (Pearson = 0.70). Bland-Altman analysis of the data showed that compared with IBP, there was a higher percentage error for MAPNIBP (30%) compared with MAPNexfin® (27%). Nexfin® and NIBP underestimated systolic BP; NIBP also underestimated diastolic BP and MAP. Trending ability for MAPNexfin® and MAPNIBP were comparable to IBP.
  
  
  CONCLUSIONS
  Non-invasive BP measurement with Nexfin® was comparable with IBP and tended to be more precise than NIBP.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Balzer
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany.
authors.forename: Marit
authors.initials: M
authors.lastname: Habicher
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Universitätsklinikum Giessen und Marburg GmbH, Rudolf-Buchheim-Straße, Giessen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Sander
authors.affiliation: Department of Internal Medicine, Klinikum Starnberg, Oßwaldstraße, Starnberg, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Sterr
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Scholz
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany.
authors.forename: Aarne
authors.initials: A
authors.lastname: Feldheiser
authors.affiliation: Centre for Musculoskeletal Surgery, Campus Charité Mitte and Campus Virchow-Klinikum, Charité- Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Müller
authors.affiliation: Centre for Musculoskeletal Surgery, Campus Charité Mitte and Campus Virchow-Klinikum, Charité- Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Perka
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Charitéplatz, Berlin, Germany sascha.treskatsch@charite.de.
authors.forename: Sascha
authors.initials: S
authors.lastname: Treskatsch
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation* / Q000379:methods*; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D019637:Orthopedic Procedures; D012307:Risk Factors
keywords: Blood pressure; Nexfin® Trial registration: ClinGov. NCT01263990; invasive arterial pressure; monitoring; non-invasive arterial pressure