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Interpreting toe and ankle pressure curves and results when using PeriFlux 6000


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The aim of this document is to provide an
understanding for the interpretation of the curves
generated during toe and ankle pressure measurements using PeriFlux 6000.

Published in: Health & Medicine
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Interpreting toe and ankle pressure curves and results when using PeriFlux 6000

  1. 1. Interpreting Curves and Results PeriFlux 6000 | peripheral pressure made intelligent 44-00316-01
  2. 2. Disclaimer The information contained in this document is intended to provide general information only. It is not intended to be, nor does it constitute, medical advice. Under no circumstances is the information contained in this document to be interpreted as a recommendation for a particular treatment for specific individuals. In all cases it is recommended that clinicians perform their own interpretations of data in conjunction with the clinical assessment of their patient. Due to Perimed’s commitment to continuous improvement of our products, all specifications are subject to change without notice. All information and content in this document is protected by copyright. All rights are reserved. Users are prohibited from modifying, copying, distributing, transmitting, displaying, publishing, selling, licensing, creating derivative works, or using any information available in or through the document for commercial or public purposes. All responsibility for any liability, loss or risk, personal or otherwise, which is incurred as a consequence, directly or indirectly, of the use and application of any of the material in this document is specifically disclaimed.
  3. 3. • Diagnosing Peripheral Arterial Disease (PAD), Critical Limb Ischemia (CLI) and Non- healing Wounds • Hands on, Tips and Tricks • Interpreting Curves and Results • Maintenance and Calibration
  4. 4. Introduction The aim of this document is to provide an understanding for the interpretation of the curves generated during pressure measurements.
  5. 5. All curves are not as perfect as this one …
  6. 6. Look for a Change in Perfusion • Baseline perfusion > 20 PU • Use local heating feature • Hold pressure until the pulsatile signal disappears Pressure (mmHg) Note that healthy controls can have a “high” occluded perfusion even though the vessels are closed. It is important is observe a clear change in perfusion. • Good occlusion PU < 20. • Clear difference between occluded vessels and return of flow. Perfusion(PU) Arm Ankle ∆ ∆ ∆ ∆
  7. 7. Recording without heat ∆ low change Pressure (mmHg) Pressure (mmHg) Perfusion(PU) Perfusion(PU) Recording with heat ∆ big change Local heat in laser Doppler probes: • Increase the signal • Facilitate interpretation • Standardize measurements Graphs recorded on the same patient without and with local heating. Standardize Measurements with Heat 0 100 50 0 100 50 Thermostatic probe 457 on toe.
  8. 8. • Calcified vessels are stiff and difficult to occlude • Common in diabetics, renal patients and patients with critical limb ischemia Incompressible Arteries Normal patient – ankle pressure 105 mmHg Pressure (mmHg) Perfusion(PU) Diabetic patient with calcified arteries Pressure (mmHg) Perfusion(PU) Arterial calcification Falsely elevated ABI ABI > 1.4 Falsely elevated ankle pressures Underestimation of PAD / CLI Clear pulsations at occlusion pressure Occlusion
  9. 9. Measure the Toe Pressure Instead • “Trust ABI when low but not when high.” • Toe pressures have proven to be an excellent option for the diagnosis of PAD in patients at risk for falsely elevated ABI >1.4 values. • Toe arteries are smaller and more easy to occlude. • Accurate toe pressures require sensitive techniques such as laser Doppler. International Consensus on the Diabetic Foot and Practical Guidelines on the Management and Prevention of the Diabetic Foot, International Working Group on the Diabetic Foot, 2012
  10. 10. Right foot: Ankle pressure = 146 mmHg ABI = 1.22 Toe pressure = 42 mmHg Baseline tcpO2 = 43 mmHg Combine Several Vascular Tests Example: Male with painful left foot and amputated toes. Results from several tests will give a better overview of the limb circulation. Here : Patient with clear PAD but no CLI. Left foot: Ankle pressure = incompressible arteries Toe pressure = no toes Baseline tcpO2 = 42 mmHg Normal Ankle Pressure and ABI. Is this really reliable or the beginning of media sclerosis and falsely elevated ABIs?
  11. 11. Adjusting Pressure Markers?
  12. 12. Standard Recording Pressure markers are automatically set at the return of flow
  13. 13. Toe pressure BloodPerfusion Time (s) Sometimes Adjustments are Required • Laser Doppler probes are sensitive to motion • Artifacts may trigger a faulty pressure registration
  14. 14. Biphasic Patterns upon Re-flow C. HØyer. et al., Reliability of laser Doppler flowmetry curve reading for measurements of toe and ankle pressures: intra- inter-observation variation, European Journal of Vascular Endovascular Surgery, 2014, in press Clear distinction between phases Overlap between phases Time (s) Perfusion(PU) 0 100 200 Time (s) Perfusion(PU) 0 100 200 Two phase (“bumps”) in the curves are: • Arterial inflow (A) – veins are closed • Unrestricted flow (V) – all vessels are open • Place pressure marker at A
  15. 15. Exclude Measurements There is always a possibility to exclude a measurement if necessary.
  16. 16. Best Practice – 3 Repetitions • Always perform three (3) consecutive measurements • Maximum variation between two pressures < 10 mmHg • If the variation is more than 10 mmHg, perform another measurement 1 145 2 146 3 128 4 143 Four consecutive ankle pressures. The 3rd pressure differs more than 10 mmHg compared to the other pressures and is discarded.
  17. 17. Summary Be consistent. Develop your own internal rules. Perform multiple measurements. Think physiologically!
  18. 18. Thank You! PeriFlux 6000 | peripheral pressure made intelligent