Validation of arterial blood pressures observed from the patient monitor; a tool for prehospital research

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Abstract

Objectives

For some time, the inaccuracies of non-invasive blood pressure measurement in critically ill patients have been recognised. Measurement difficulties can occur even in optimal conditions, but in prehospital transportation vehicles, problems are exacerbated. Intra-arterial pressures must be used as the reference against which to compare the performance of non-invasive methods in the critically ill patient population. Intra-arterial manometer data observed from the patient monitor has frequently been used as the reference against which to assess the accuracy of noninvasive devices in the emergency setting. To test this method’s validity, this study aimed to determine whether numerical monitor pressures can be considered interchangeable with independently sampled intra-arterial pressures.

Methods

Intensive Care Unit nurses were asked to document arterial systolic, diastolic and mean pressures numerically displayed on the patient monitor. Observed pressures were compared to reference intra-arterial pressures independently recorded to a computer following analogue to digital conversion. Differences between observed and recorded pressures were evaluated using the Association for the Advancement of Medical Instrumentation (AAMI) protocol. Additionally, two-level linear mixed effects analyses and Bland-Altman comparisons were undertaken.

Results

Systolic, diastolic and integrated mean pressures observed during 60 data collection sessions (n = 600) fulfilled AAMI protocol criteria. Integrated mean pressures were the most robust. For these pressures, mean error (reference minus observed) was 0.5 mm Hg (SD 1.4 mm Hg); 95% CI (two-level linear mixed effects analysis) 0.4–0.6 mm Hg; P < 0.001. Bland-Altman plots demonstrated tight 95% limits of agreement (−2.3 to 3.2 mm Hg), and uniform agreement across the range of mean blood pressures.

Conclusions

Integrated mean arterial pressures observed from a well maintained patient monitor can be considered interchangeable with independently sampled intra-arterial pressures and may be confidently used as the reference against which to test the accuracy of non-invasive blood pressure measuring methods in the prehospital or emergency setting.

Keywords

validation blood pressure monitoring prehospital non-invasive critical illness 
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Notes

Acknowledgments

The authors would like to express their gratitude and admiration to the patients and families who participated in this study. This study relied on the cooperation of the nurses in the Intensive Care Unit at Flinders Medical Centre, and they are thanked for their professional and enthusiastic participation. Thanks are also extended to the hospital’s Biomedical Engineers for their willingness to share their expertise. Philips Medical Systems Australasia provided a blood pressure module that incorporated an analogue output jack for use during bedside data collection.

References

  1. 1.
    Bruner JM, Krenis LJ, Kunsman JM, et al. Comparison of direct and indirect methods of measuring arterial blood pressure, part III. Med Instrum. 1981;15:182–8.PubMedGoogle Scholar
  2. 2.
    Davis RF. Clinical comparison of automated auscultatory and oscillometric and catheter-transducer measurements of arterial pressure. J Clin Monit. 1985;1:114–9.CrossRefPubMedGoogle Scholar
  3. 3.
    Gloyna DF, Huber P, Abston P, et al. A comparison of blood pressure measurement techniques in the hypotensive patient (Abstract). Anesth Analg. 1984;63:222.Google Scholar
  4. 4.
    Gourdeau M, Martin R, Lamarche Y, et al. Oscillometry and direct blood pressure: a comparative clinical study during deliberate hypotension. Can J Anaesth. 1986;33:300–7.CrossRefGoogle Scholar
  5. 5.
    van Bergen FH, Weatherhead DS, Treloar AE, et al. Comparison of indirect and direct methods of measuring arterial blood pressure. Circulation. 1954;10:481–90.Google Scholar
  6. 6.
    van Egmond J, Hasenbos M, Crul JF. Invasive v. non-invasive measurement of arterial pressure. Comparison of two automatic methods and simultaneously measured direct intra-arterial pressure. Br J Anaesth. 1985;57:434–44.CrossRefPubMedGoogle Scholar
  7. 7.
    Venus B, Mathru M, Smith RA, et al. Direct versus indirect blood pressure measurements in critically ill patients. Heart Lung. 1985;14:228–31.PubMedGoogle Scholar
  8. 8.
    Low RB, Martin D. Accuracy of blood pressure measurements made aboard helicopters. Ann Emerg Med. 1988;17:604–12.CrossRefPubMedGoogle Scholar
  9. 9.
    Morley AP. Prehospital monitoring of trauma patients: experience of a helicopter emergency medical service. Br J Anaesth. 1996;76:726–30.PubMedGoogle Scholar
  10. 10.
    Runcie CJ, Reeve W, Reidy J, et al. A comparison of measurements of blood pressure, heart-rate and oxygenation during inter-hospital transport of the critically ill. Intensive Care Med. 1990;16:317–22.CrossRefPubMedGoogle Scholar
  11. 11.
    Runcie CJ, Reeve WG, Reidy J, et al. Blood pressure measurement during transport. A comparison of direct and oscillotonometric readings in critically ill patients. Anaesthesia. 1990;45:659–65.CrossRefPubMedGoogle Scholar
  12. 12.
    SunTech Medical. Evaluation of a non-invasive blood pressure monitoring technology during emergency transport conditions as compared to the ProPaq LT. Morrisville, NC, USA; 2008. 82-0066-00 rev A.Google Scholar
  13. 13.
    Hewlett Packard. An algorithm for reduction of respiratory artifact in pulmonary artery pressure measurements. Application Note; 5953–7352; 1989.Google Scholar
  14. 14.
    Glantz SA, Tyberg JV. Determination of frequency response from step response: application to fluid-filled catheters. Am J Physiol. 1979;236:H376–8.PubMedGoogle Scholar
  15. 15.
    Kleinman B, Powell S, Kumar P, et al. The fast flush test measures the dynamic response of the entire blood pressure monitoring system. Anesthesiology. 1992;77:1215–20.CrossRefPubMedGoogle Scholar
  16. 16.
    Muecke S, Bersten AD, Plummer J. The Mean Machine; accurate non-invasive blood pressure measurement in the critically ill patient. J Clin Monit Comp 2009; 23: 283–297.Google Scholar
  17. 17.
    Agilent Technologies. Agilent component monitoring system & V24 and V26. Concepts Guide. USA: Agilent Technologies, Inc.; 2000. M1046-9301L.Google Scholar
  18. 18.
    AAMI. ANSI/AAMI SP10:2002 & ANSI/AAMI SP10:2002/A1:2003. American National Standard. Manual, electronic, or automated sphygmomanometers; 2002.Google Scholar
  19. 19.
    Bland JM, Altman DG. Measuring agreement in method comparison studies. Stat Methods Med Res. 1999;8:135–60.CrossRefPubMedGoogle Scholar
  20. 20.
    Vangeneugden T, Laenen A, Geys H, et al. Applying linear mixed models to estimate reliability in clinical trial data with repeated measurements. Control Clin Trials. 2004;25:13–30.CrossRefPubMedGoogle Scholar
  21. 21.
    Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1(8476):307–10.PubMedGoogle Scholar
  22. 22.
    Glantz SA. Primer of biostatistics. 6th ed. USA: McGraw-Hill; 2005.Google Scholar
  23. 23.
    Bur A, Hirschl MM, Herkner H, et al. Accuracy of oscillometric blood pressure measurement according to the relation between cuff size and upper-arm circumference in critically ill patients. Crit Care Med. 2000;28:371–6.CrossRefPubMedGoogle Scholar
  24. 24.
    Gibbs NM, Larach DR, Derr JA. The accuracy of Finapres noninvasive mean arterial pressure measurements in anesthetized patients. Anesthesiology. 1991;74:647–52.CrossRefPubMedGoogle Scholar
  25. 25.
    Hirschl MM, Binder M, Herkner H, et al. Accuracy and reliability of noninvasive continuous finger blood pressure measurement in critically ill patients. Crit Care Med. 1996;24:1684–9.CrossRefPubMedGoogle Scholar
  26. 26.
    Walia S, Sutcliffe AJ. The relationship between blood glucose, mean arterial pressure and outcome after severe head injury: an observational study. Injury. 2002;33:339–44.CrossRefPubMedGoogle Scholar
  27. 27.
    Ream AK. Systolic, diastolic, mean or pulse: which is the best measurement of arterial pressure? In: Gravenstein JS, Newbower RS, Ream AK, et al., editors. Essential noninvasive monitoring in anesthesia. USA: Grune & Stratton; 1980. p. 53–74.Google Scholar
  28. 28.
    Runciman WB, Ilsley AH, Rutten AJ. Systemic arterial blood pressure. Anaesth Intensive Care. 1988;16:54–7.PubMedGoogle Scholar
  29. 29.
    Falsetti HL, Mates RE, Carroll RJ, et al. Analysis and correction of pressure wave distortion in fluid-filled catheter systems. Circulation. 1974;49:165–72.PubMedGoogle Scholar
  30. 30.
    Gardner RM. Direct blood pressure measurement-dynamic response requirements. Anesthesiology. 1981;54:227–36.CrossRefPubMedGoogle Scholar
  31. 31.
    Runciman WB, Rutten AJ, Ilsley AH. An evaluation of blood pressure measurement. Anaesth Intensive Care. 1981;9:314–25.PubMedGoogle Scholar
  32. 32.
    Wellnhofer E, Combe V, Oswald H, et al. High fidelity correction of pressure signals from fluid-filled systems by harmonic analysis. J Clin Monit Comput. 1999;15:307–15.CrossRefPubMedGoogle Scholar
  33. 33.
    Hansen AT. Pressure measurement in the human organism. Acta Physiol Scand Suppl. 1949;19:11–231.Google Scholar
  34. 34.
    Kleinman B. Understanding natural frequency and damping and how they relate to the measurement of blood pressure. J Clin Monit. 1989;5:137–47.CrossRefPubMedGoogle Scholar
  35. 35.
    Cohn JN. Blood pressure measurement in shock. Mechanism of inaccuracy in auscultatory and palpatory methods. JAMA. 1967;199:118–22.CrossRefPubMedGoogle Scholar
  36. 36.
    Cohn JN, Daddario RC. Mechanism of disappearance of Korotkoff sounds in clinical shock. Circulation. 1965;31–32:69.Google Scholar
  37. 37.
    Cohn JN, Luria MH. Studies in clinical shock and hypotension. The value of bedside hemodynamic observations. JAMA. 1964;190:113–8.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Department of Critical Care MedicineFlinders UniversityAdelaideAustralia
  2. 2.Intensive and Critical Care UnitFlinders Medical CentreAdelaideAustralia
  3. 3.Pain Management UnitFlinders Medical CentreAdelaideAustralia

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