Canadian Journal of Anesthesia

, Volume 46, Issue 5, pp 488–496 | Cite as

Accuracy of radial artery blood pressure determination with the Vasotrac™

  • Kumar G. Belani
  • Joseph J. Buckley
  • Marius O. Poliac



To evaluate the accuracy of a new non-invasive method (Vasotrac™) to measure blood pressure (BP) with accompanying arterial wave-form and pulse-rate display when compared with BP and waveform measured invasively.


Healthy volunteers (n=53) served as subjects for the study. Blood pressures and waveforms obtained via a radial artery catheter (IABP) were compared with non-invasive measurements obtained every 12–15 beats by the new system (Vasotrac BP) from the opposite radial artery. In a sub-group of volunteers (n= 11), BP was acutely increased and decreased with isoproterenol, phenylephrine and sodium nitroprusside. Data were analyzed by determining correlation and agreement between the two systems of measurement. Waveforms obtained by the two systems were qualitatively examined.


Non-invasive BP measured every 12–15 beats by the Vasotrac correlated with IABP (systolic r2 = 0.89; diastolic r2 = 0.88; mean r2 = 0.94). The actual values obtained by the two methods agreed closely with > 90% of readings being within 2SDs when plotted by the Bland Altman method. This was also true during vasoactive drug infusion when BP changed acutely and swiftly. During this dynamic period, Vasotrac BP accurately tracked the changes in IABP with correlations (systolic r2= 0.82; diastolic r2 = 0.89; mean r2 = 0.95) and close agreement (> 90% of readings were within 2 SDs in the Bland Altman plot). Waveforms displayed by the two systems were qualitatively very similar. Pulse rates measured by the two systems were identical.


The Vasotrac system displayed an arterial waveform which was similar to that obtained directly and measured BP and pulse rate accurately. It should be a convenient device to measure BP continually in a non-invasive fashion.


Radial Artery Vasoactive Drug Blood Pressure Reading Arterial Waveform Ulnar Neuropathy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Évaluer l’exactitude d’une nouvelle méthode non effractive de mesure (Vasotrac™) de la tension artérielle (TA), avec les graphiques qui l’accompagnent montrant les ondes artérielles et les fréquences de pouls, en la comparant avec une méthode effractive et ses graphiques.


Des volontaires en santé (n = 53) ont participé à l’étude. Les tensions artérielles et les courbes artérielles obtenues au moyen d’un cathéter de l’artère radiale (TAIA) ont été comparées aux mesures non effractives obtenues à tous les 12–15 battements de l’artère radiale opposée avec le nouveau système (TA Vasotrac). Chez des volontaires (n = 11) d’un sous-groupe, on a provoqué une hausse et une baisse soudaines de la TA avec de l’isoprotérénol, de la phényléphrine et du nitroprussiate de sodium. Les données ont été analysées en déterminant la corrélation et la concordance entre les deux systèmes de mesure. On a examiné les caractéristiques des graphiques obtenus des deux systèmes.


Les mesures non effractives de TA faites tous les 12–15 battements avec le Vasotrac sont en corrélation avec celles du système de TAIA(r2 systolique = 0,89; r2 diastolique = 0,88; moyenne de r2 = 0,94). Les tracés, d’après Bland Altman, des valeurs provenant des deux systèmes concordaient étroitement, indiquant > 90% des mesures qui se situent à l’intérieurs de 2 écarts-types. Il y a eu la même corrélation pendant la perfusion de médicament vasoactif. Pendant cette période dynamique, la TA Vasotrac a suivi avec précision les changements de la TAIA avec des mesures correspondantes (r2 systolique = 0,82; r2 diastolique = 0,89; moyenne de r2 = 0,95) et d’étroites concordances (> 90% à l’intérieur de 2 écarts-types). Les graphiques produits par les deux systèmes étaient qualitativement très similaires. Les fréquences de pouls étaient identiques.


Le système Vasotrac a permis de visualiser des ondes artérielles similaires à celles qui ont été obtenues directement, et a mesuré la TA et la fréquence de pouls avec précision. C’est un appareil qui peut être pratique pour mesurer continûment la TA d’une manière non effractive.


  1. 1.
    ASA Standards, Guidelines and Statements, October 1997. The American Society of Anesthesiologists, 1997: 2–3.Google Scholar
  2. 2.
    Eichhorn JH, Cooper JB, Cullen DJ, Maier WR, Philip JH, Seeman RG. Standards for patient monitoring during anesthesia at Harvard Medical School. JAMA 1986; 256: 1017–20.PubMedCrossRefGoogle Scholar
  3. 3.
    Kenner T. Arterial blood pressure and its measurement. Basic Res Cardiol 1988; 83: 107–21.PubMedCrossRefGoogle Scholar
  4. 4.
    French Society of Anesthesia and Intensive Care. Arterial catheterisation and invasive measurement of blood pressure in anaesthesia and intensive care in adults. (French) Ann Fr Anesth Reanim 1995; 14: 444–53.Google Scholar
  5. 5.
    Gorback MS, Quill TJ, Graubert DA. The accuracy of rapid oscillometric blood pressure determination. Biomed Instrum Technol 1990; 24: 371–4.PubMedGoogle Scholar
  6. 6.
    American National Standard for Interchangeability and Performance of Resistive Bridge Type Blood Pressure Transducers. The Association for the Advancement of Medical Instrumentation. 1986: 31–8.Google Scholar
  7. 7.
    Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: 307–10.PubMedGoogle Scholar
  8. 8.
    Siegel LC, Broek-Utne JG, Brodsky JB. Comparison of arterial tonometry with radial artery catheter measurements of blood pressure in anesthetized patients. Anesthesiology 1994; 81: 578–84.PubMedCrossRefGoogle Scholar
  9. 9.
    Sy WP. Ulnar nerve palsy possibly related to use of automatically cycled blood pressure cuff. Anesth Analg 1981; 60: 687–8.PubMedCrossRefGoogle Scholar
  10. 10.
    Bause GS, Weintraub AC, Tanner GE. Skin avulsion during oscillometry. J Clin Monit 1986; 2: 262–3.PubMedCrossRefGoogle Scholar
  11. 11.
    Showman A, Betts EK. Hazard of automatic noninvasive blood pressure monitoring (Letter). Anesthesiology 1981; 55: 717–8.PubMedCrossRefGoogle Scholar
  12. 12.
    Zylicz Z, Nuyten FJJ, Notermans SLH, Koene RAP. Postoperative ulnar neuropathy after kidney transplantation. Anaesthesia 1984; 39: 1117–20.PubMedCrossRefGoogle Scholar
  13. 13.
    Hutton P, Dye J, Prys-Roberts C. An assessment of the Dinamap 845. Anaesthesia 1984; 39: 261–7.PubMedCrossRefGoogle Scholar
  14. 14.
    Kemmotsu O, Ueda M, Otsuka H, Yamamura T, Winter DC, Eckerle JS. Arterial tonometry for noninvasive, continuous blood pressure monitoring during anesthesia. Anesthesiology 1991; 75: 333–40.PubMedCrossRefGoogle Scholar
  15. 15.
    Wesseling KH. Finger arterial pressure measurement with Finapres. Z Kardiol 1996; 85(Suppl 3): 38–44.PubMedGoogle Scholar
  16. 16.
    Gmvenstein JS, Paulus DA, Feldman J, Mclaughlin G. Tissue hypoxia distal to a Penaz finger blood pressure cuff. J Clin Monk 1985; 1: 120–5.CrossRefGoogle Scholar
  17. 17.
    Stokes DN, Clutton-Brock T, Paul C, Thompson JM, Hutton P. Comparison of invasive and non-invasive measurement of continuous arterial pressure using the Finapres. Br J Anaesth 1991; 67: 26–35.PubMedCrossRefGoogle Scholar

Copyright information

© Canadian Anesthesiologists 1999

Authors and Affiliations

  • Kumar G. Belani
    • 1
  • Joseph J. Buckley
    • 1
  • Marius O. Poliac
    • 2
  1. 1.Department of AnesthesiologyUniversity of Minnesota Medical SchoolMinneapolis
  2. 2.Medwave Inc.Arden HillsUSA

Personalised recommendations