Digit Plethysmography and Pressures Flashcards
Capabilities of digital plethysmography and pressures?
- help detect presence of arterial disease
- differentiate fixed arterial obstruction from vasospasm
- assess effects of treatment
Limitations of digital plethysmography and pressures?
- Quality of tracings greatly affected by vascoconstrictions (cold, smoking, nervous)
- With VOLUME plethysmography, cuffs applied too tightly, can obliterate or diminish the pulse waves
- With PHOTO plethysmography improper contact with skin surface will cause poor results
- bandages, ulcerations, gangrene, tremors
Patient positioning with digital plethysmography and pressures?
Toe evaluation: supine with some elevation of head
Finger evaluation: sitting with arms resting on pillow placed on patients lap
Toe technique with digital plethysmography and pressures?
- Patient should be kept as warm as possible
- Done in combination of complete LE arterial exam, or a limited version such as an ABI
What is the appropriate sized toe cuff?
width at least 1.2 times that of the toe
What is the method for digital plethysmography and pressures?
- digit cuff is placed at base of great toe
- photocell securely attached to plantar side of toe using double-stick tape or velcro strap
- pulses recorded; paper speed is slowed to 5mm/sec
- while pulsations are recorded, cuff is inflated to 20-30 mmHg above highest brachial P.
- no pulsations should be seen
- cuff is slowly deflated, watching for return of first pulse to define the pressure level
- can also be with volume plethysmography
Technique for fingers without cold stress:
- Upper extremity arterial study is completed initially
- Evaluate doppler signals and obtain pressures
- Doppler exam of the palmar arch, to verify patency
- Apply finger cuffs
- Pressures and waveforms obtained
What is a finger cuff size?
2 - 2.5 cm
Why would fingers be evaluated with cold stress?
Performed in cases of symptoms occurring due to cold sensitivity
Technique for fingers with cold stress:
- After resting study is performed, hands are immersed in ice cold water for 3 minutes if possible
- Following cold stress, waveforms and pressures are obtained: immediately after and five minutes after
- Document patient symptoms, skin color observations and other pertinent findings on the report form
Normal waveform qualities:
- sharp upstroke during peak systole
- prolonged down-stroke with notch approximately half way down
- amplitude is usually greater than toe tracings
Abnormal obstructive waveform qualities:
- occlusion located anywhere proximal to the tip of the finger causes the pulse to assume an “obstructive” form
- slow upslope to rounded peak
- downslope that bows away from baseline
Abnormal peaked waveform qualities:
- upslope is lower than normal
- sharp, (anacrotic) notch is present
- reflected wave located high on the downslope
- has characteristics of both normal and obstructive waveforms
What does organic (fixed) obstructive disease display?
Abnormal doppler arterial signals, systolic pressures and PPG tracings
What does functional (intermittent) obstructive disease display?
Normal doppler arterial signals, systolic pressures, and/or PPG tracings; but abnormal findings after cold stimulation
