Ultrasound assessment of the upper extremity - PowerPoint Presentation

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Ultrasound assessment of the upper extremityHarry Hulbert Holdorf PhD, MPA, RDMS, RVT, LRT(AS)Slide2

ContentsVascular Technology

Lecture 6Ultrasound Assessment of the Upper ExtremityAnatomy of the upper extremity including palmar archesDoppler Segmental Pressures of the upper extremityThe Allen TestDuplex/Color Flow Imaging (UE)

Upper Extremity Arterial Doppler ProtocolSlide3

Upper extremity arterial examination. Point of originSlide4

Arteries of the Upper ExtremitySlide5

Arteries of the Upper extremitySlide6

Arteries of the Upper ExtremitySlide7

Upper Extremity Arteries1. Subclavian artery

Runs laterally to outer border of 1st rib becoming the axillary arterySome branches: vertebral, thyrocervical, costocervical.2. Axillary arteryAfter giving off several branches, becomes brachial artery3. Brachial arteryBranches into the radial and ulnar arteries a the inner aspect of the elbow (AKA the antecubital fossa)Slide8

4. Radial arteryTravels down lateral side of forearm into hand, branching to form:Superficial palmer (volar) arch

Terminates in deep palmer arch by joining deep branch of ulnar artery5. Ulnar arteryTravels down medial side of forearm into hand, branching to form:Deep palmar (volar) branchTerminates in superficial palmar archPredominate source of blood flow to the handSlide9

6. Superficial palmar (volar) arch includes:Distal portion of the ulnar arteryBranch of the radial artery7. Deep palmar arch includes:

Deep palmar arch of the ulnar arteryDistal portion of the radial artery8. Digital arteries arise from the palmar arches and extend into the fingers dividing into lateral and medial branches.Slide10
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Doppler Segmental Pressures of the upper extremityPatient positioning:

Supine with arms relaxed at the patient’s sideCuffs should be on snug, but not too tight.Technique: 12 x 40 cm cuff placed snugly on the upper arm: 10 x 40 cuff on the forearm bilaterallyBrachial artery used to obtain upper arm BP; Radial and ulnar arteries used to obtain the forearm pressure.Slide12

Pressures are combined with Doppler velocity wave forms from the sites previously describe.Slide13

upper extremity segmental pressure

1)   Bilateral brachial arm pressures no more than 20 mmHg2)   Finger/Brachial Index  a. Normal    >0.75  b. Abnormal <0.753)   Pressure measurements between adjacent cuff sites on the same arm should 

not differ by more than 10 mmHg (brachial and forearm)

4)   Pressure measurements differences at the same cuff level on opposite arms 

should not exceed 20 mmHg

5)   The pressures in the radial and ulnar arteries should be within 5-10 mmHg of one 

another. A pressure difference  >= 20mmHG indicates obstruction in the vessel with 

the lower pressureSlide14

What mm/Hg difference from arm to arm constitutes an abnormal upper extremity segmental pressure?Pressure measurements differences at the same cuff level on opposite arms should not exceed 20

mmHg.Slide15

Doppler Segmental Pressures of the Upper Extremity

 What is the Allen Test and how is it performed?The test is performed to estimate palmar arch patency. A technologist compresses the radial artery while patient closes ipsilateral fist to cause pallor, but in the meantime, this action will increase resistance.

What mm/Hg difference from arm to arm constitutes an abnormal upper extremity segmental

pressure?

The differences of pressure measurements at the cuff level on the other arms should not go over than 20 mmHg.Slide16

The Allen TestOnly done to evaluate patency of the palmer archSlide17

The Allen test The

hand is normally supplied by blood from the ulnar and radial arteries. The arteries undergo anastomosis  in the hand. Thus, if the blood supply from one of the arteries is cut off, the other artery can supply adequate blood to the hand. A

small amount of people lack this dual blood supply

.

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1) The hand is elevated and the patient/person is asked to make a fist for about 30 seconds.2) Pressure is applied over the ulnar and the radial arteries so as to occlude both of them.3) Still elevated, the hand is then opened. It should appear blanched (pallor can be observed at the finger nails).

4) Ulnar pressure is released and the color should return in 7 seconds.Inference: Ulnar artery supply to the hand is sufficient and it is safe to cannulate/prick the radialIf color does not return or returns after 7–10 seconds, the test is considered positive and the ulnar artery supply to the hand is not sufficient. The radial artery therefore cannot be safely pricked/cannulated.Slide20

Allen Test InterpretationsNormalReappearance of the normal color to indicate the ulnar artery is providing flow to the palmar arch

AbnormalColor does not reappear to indicate an ulnar artery occlusion or palmar arch obstructionSlide21

Allen Test LimitationsExcessive dorsiflexion of wrist may compress radial and ulnar arteries leading to a false positive test.

If hand is opened, fingers forcibly extended; the skin over palm can be stretched, which could lead to pallor due to compression of small vesselsSlide22

Allen Test documentationUse a PPG (photoplethysomography) on the index finger to document arterial pulsations before and after the “clinched fist”.

Although more difficult to compress, the ulnar artery can be evaluated similarly to assess radial artery flow.Slide23

Duplex Color Flow Imaging (UE)Capabilities

Localize stenosis/occlusion; evaluate degree of stenosisDetermine the presence/absence of aneurysmPost-op study: hemodialysis access or arterial bypass graftDirect Artero- Venous fistula (AVF) or other unusual abnormalitySlide24

LimitationsLimited access to extremity (e.g.,) dressings, skin staples or sutures, open wounds IV site…Pertaining to hemodialysis access grafts:

Graft angulationDifficult to adequately evaluate the outflow vein in an obese patientPatient positioningPatient is supine with small pillow under headExtremity close to examinerArm is at a 45 degree angle from the body, and extremity rotated “Pledge Position”Slide25

Physical PrinciplesDuplex scanning: combination of real-time B-mode imaging (gray scale evaluation) and Doppler spectral analysisDoppler Color Flow Imaging: Doppler information is displayed on image after evaluated for phase (direction toward or away from the transducer) and its frequency content (hue or shade of the color)

Sample size for acquiring pulsed Doppler information is usually 1-1.5mm. Size is increased incrementally if needed.Slide26

Technique: Native ArteriesUtilize a 7 or 5 MHz linear array transducerNeck vessels identified with attention to innominate artery on the right. The LCCA braches off the Arch.

Color / duplex scanning is also used to evaluate the following:SubclavianAxillaryBrachialRadialUlnarPalmar arch (if needed)Slide27

Example of an UE Arterial SignalSlide28

NOTE: It is uncommon for arteries in the upper extremities to become stenotic. Main indication for ultrasound assessment is for evaluation of dialysis access grafts.Slide29

Dialysis access is an entranceway into the bloodstream that lies completely beneath

the skin and is easy to use. The access is usually in the arm, but sometimes in the leg, and allows blood to be removed and returned quickly, efficiently, and safely during dialysis or, less commonly, for other procedures requiring frequent access to the circulation.Slide30
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Access Grafts Technique Hemodialysis AccessAuscultate the access for bruit and or palpate for a “thrill” (vibration). A patent dialysis access, as well as a stenotic one can produce a “thrill.”

Utilize a 7 or 5 MHz linear array transducerSlide32

Evaluate dialysis access grafts as follows:Inflow artery

Arterial anastomosisContinue through the body of the graftObserve of aneurysm, puncture sites, peri-graft fluidIf color available, observe the image for flow changes, turbulence, flow channel changesVenous anastomosisOutflow veinSlide33

NOTE: Dialysis access (e.g. Brescia-Cimino fistula) assessment sites include: inflow artery, anastomosis, outflow veinSlide34

Brescia-Cimino AccessSlide35

Upper Extremity Arterial DopplerProtocol

Includes an evaluation of bilateral extremity arterial waveforms of the common carotid, subclavian, brachial, ulnar, and radial arteries utilizing spectral Doppler. The goal is to document any hemodynamic changes related to vessel narrowing or stenosisSlide36

Patient Prep: NonePatient is instructed to remove clothing from the waist up- gown open in the frontTransducer:

The highest frequency linear transducer possible- usually 5 to 15 MHz.Continuous wave “Pencil-Probe is transducer of choice.Paperwork: Fill out Upper Extremity Arterial Doppler Worksheet completely (Department specific). Document reason for exam and all pertinent history.

Record all measurements and fill in comments. Obtain reports of previous exams or other pertinent studies.Slide37

ProtocolPatient is instructed to relax spine on the bed. A blood pressure cuff is placed above the brachial artery on the upper arm. The cuff is inflated and a systolic pressure of the brachial artery is obtained. This number is documented. The brachial artery spectral waveform is evaluated for flow characteristics (Triphasic, biphasic, or monophasic). Pressure differences are compared segmentally and contra laterally.Slide38

A blood pressure cuff is placed on the forearm and systolic pressures are obtained of the radial and ulnar arteries. Once again, flow characteristics are evaluated and ratios are calculated using the brachial pressure.Examination is repeated on the contralateral arm.Slide39

Doppler Waveform AnalysisThe following spectral Doppler images must be obtained during the procedure:

Right CarotidRight SubclavianRight AxillaryRight BrachialRight RadialRight UlnarWaveform analysis is repeated on the left arm