UltrasoUnd Physics & instrUmentation - Pegasus Lectures

1.2 Power .........................................................................................................................................826
1.3 Why Electrical Principles Matter to Vascular Principles ...........................................................827
2. Relating Electrical Signals to Physical Parameters .............................................................................827
2.1 Information Display ...................................................................................................................827
2.1.1 The Cathode Ray Tube (CRT) .....................................................................................827
2.1.2 Strip Chart ....................................................................................................................827
2.1.3 Calibration of a strip chart ...........................................................................................828
3. Two-Wire vs. Four-Wire Measurements and Calibration ...................................................................828
3.1 AC vs. DC Coupling ..................................................................................................................829
3.1.1 AC (alternating current) ...............................................................................................829
3.1.2 Direct Current ..............................................................................................................829
3.1.3 Choosing the Appropriate Coupling for Indirect Arterial and Venous Testing ............830
4. Plethysmography .................................................................................................................................831
4.1 Displacement (pneumatic cuff) Plethysmography: ...................................................................831
4.2 Strain-gauge Plethysmography ..................................................................................................831
4.3 Impedance Plethysmography (IPG)...........................................................................................831
4.4 Inflow and Outflow Studies ......................................................................................................832
4.4.1 Venous Capacitance/Venous Outflow (VO/VC) ..........................................................832
4.5 Photoplethysmography ..............................................................................................................833
4.5.1 Venous Reflux Testing .................................................................................................833
4.5.2 Arterial Testing with Photoplethysmography ..............................................................835
5. Pressure Measurements .......................................................................................................................837
5.1 Methods of Pressure Measurements ..........................................................................................837
5.1.1 Palpatory method ........................................................................................................837
5.1.2 Ausculatory method .....................................................................................................837
5.1.3 Flow Meter (Doppler) ..................................................................................................838
5.2 The Correct Cuff Size ................................................................................................................838
6. Arterial Pressure Measurements ..........................................................................................................839
6.1 Lower Extremity Segmental Pressures ......................................................................................839
6.2 Upper Extremity Arterial Pressures ...........................................................................................841
7. Reactive Hyperemia ............................................................................................................................842
8. Skin Temperature and Skin Changes ...................................................................................................842
9. Occlusion Pressures .............................................................................................................................843
10. Oculoplethysmography (OPG) ...........................................................................................................843
11. Miscellaneous ......................................................................................................................................845
11.1 Arteriovenous Fistula ................................................................................................................845
11.2 Autogenous Arteriovenous Fistulae...........................................................................................845
11.3 Pseudoaneurysm ........................................................................................................................845
12. Transcutaneous Oximetry ....................................................................................................................845
13. Transcranial Doppler ...........................................................................................................................846
13.1 General.......................................................................................................................................846
13.2 Identifying Vessels .....................................................................................................................847
13.3 Technical Limitations: ...............................................................................................................848
aPPenDIX b: Cardiovascular Principals
Introduction ................................................................................................................................................849
1. The Circulatory System .......................................................................................................................849
1.1 Pulmonary vs. Systemic Circulatory Components ....................................................................850
1.2 Pulmonary vs. Systemic Circulation .........................................................................................850
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Pegasus Lectures, Inc.