Photoplethysmography hand-perfusion study
Palmar Arch Test / AV Fistula
The palmar arch test is an objective, PPG-based version of the modified Allen test: it occludes the radial and ulnar arteries and watches the digit pulse return to confirm the hand's collateral supply — the same hand-perfusion check that guides arterial cannulation and dialysis-access planning.
Place the PPG sensor
A photoplethysmography sensor on a finger tracks the digit pulse supplied through the palmar arch.
Occlude both arteries
The radial and ulnar arteries are compressed at the wrist and the operator marks the start of occlusion — the digit pulse flattens.
Release one & read recovery
One artery is released; a prompt, full return of the pulse confirms that vessel and the arch can supply the hand on their own.
The hand is normally fed by two arteries — the radial and the ulnar — joined by the palmar arches, so that either vessel can supply the hand on its own. The palmar arch test checks that collateral pathway before anything that depends on a single artery: radial-artery cannulation or harvest, arterial line placement, or planning and following a dialysis access.
- Non-invasive and painless
- Confirms the hand's collateral (palmar-arch) supply
- An objective PPG reading in place of the subjective Allen test
VasoGuard runs the test with photoplethysmography (PPG) rather than relying on the examiner's eye. A PPG sensor on a finger records the digit pulse while the operator compresses both the radial and ulnar arteries at the wrist — marking the begin-occlusionpoint — and the waveform flattens as inflow stops. One artery is then released, marking the end-occlusion point.
How the digit pulse comes back tells the story. A prompt, full return of the waveform means that artery and the palmar arch can perfuse the hand on their own. A pulse that stays flat, returns slowly, or recovers only partially points to an incomplete arch or a diseased vessel. The system displays the waveform with the begin- and end-occlusion cursors and reports heart rate, pulse amplitude, and rise time for the recovery.
- Digital PPG waveform at the fingertip
- Operator-marked begin- and end-occlusion cursors
- Heart rate, pulse amplitude, and rise-time readouts
The same digit-PPG perfusion signal supports dialysis-access work on both ends of the timeline:
- Before access creation— documenting the hand's arterial supply and palmar-arch collateral, so a fistula or graft can be sited without compromising the hand.
- After access creation— screening for access-related hand ischemia (“steal”) by recording the digit pulse while the access, radial, or ulnar artery is compressed in turn — the physiologic basis of the digital-brachial index used to grade steal.
This is a physiologicassessment of hand perfusion. It does not measure access flow volume (Qa) or grade an anastomotic or outflow stenosis — those are the province of duplex ultrasound surveillance under the KDOQI guidelines, which the PPG study complements rather than replaces.
Palmar-arch / hand-perfusion testing supports:
- Confirming collateral hand supply before radial-artery cannulation, arterial-line placement, or radial harvest
- Assessing hand circulation before dialysis-access creation
- Screening for access-related hand ischemia after a fistula or graft is in place
- Documenting hand perfusion objectively, with a saved waveform for the record
Replacing the subjective “watch the hand flush” read with a recorded PPG waveform makes the result objective, repeatable, and reportable.
VasoGuard's Palmar Arch study runs as a guided protocol:
- Digital PPG waveform with operator-marked begin- and end-occlusion cursors
- Heart-rate, pulse-amplitude, and rise-time readouts for the recovery
- Multi-finger sites, high-resolution waveform display, and report export
Pair it with VasoGuard's upper-extremity and segmental pressure studies for digital pressures and the digital-brachial index.