🖐️ Digital Vasospasm Attack Simulator

Baseline Digital Perfusion

Healthy resting blood flow keeps fingers warm and pink.

• 100%: Resting digital flow (normalized baseline)
• 34°C: Skin temperature (warm capillary bed)
• Relaxed: Vessel tone (normal sympathetic tone)
• ~5%: Raynaud prevalence (general population)

Normal digital circulation

Arterioles stay open, capillaries fully perfused, tissue oxygenated.

Sympathetic vascular tone

Baseline nerve signaling keeps vessel diameter steady and responsive.

Vasospasm Trigger — Cold or Stress Onset

Cold exposure or stress fires an exaggerated sympathetic vasospasm.

• <60s: Onset latency (cold-to-constriction)
• Hyperactive: Alpha-2 receptors (digital artery smooth muscle)
• Cold, stress: Common triggers (emotional or thermal)
• Rapid: Flow drop rate (seconds to minutes)

Sympathetic overdrive

Alpha-2c receptors overreact, clamping digital artery smooth muscle.

Rapid arterial narrowing

Vessel lumen narrows sharply, cutting inflow within seconds.

White Phase — Ischemic Pallor

Near-total flow cutoff leaves the finger pale and numb.

• <10%: Blood flow (of baseline)
• Chalk white: Skin color (ischemic pallor)
• Numbness: Sensation (reduced nerve perfusion)
• 2–10 min: Typical duration (severity dependent)

Arterial shutdown

Digital artery nearly closed, capillary bed drains of blood.

Ischemic symptoms

Pallor, coldness, and numbness follow the flow collapse.

Blue Phase — Cyanotic Pooling

Trapped deoxygenated blood stagnates, turning the finger blue.

• ~10–20%: Blood flow (sluggish, stagnant)
• Low: Oxygen saturation (deoxyhemoglobin dominant)
• Cyanotic blue: Skin color (venous stasis)
• Tingling: Sensation (partial reperfusion signals)

Venous stasis pooling

Residual trapped blood desaturates, deepening the cyanotic tint.

Tingling nerve signals

Partial capillary trickle sparks tingling as tissue starves.

Red Phase — Reactive Hyperemia

Vasospasm releases and blood surges back, flushing the finger red.

• 150–200%: Peak blood flow (rebound overshoot)
• Bright red: Skin color (reactive hyperemia)
• Throbbing pain: Sensation (reperfusion nerve firing)
• ~15–20 min: Recovery time (total attack duration)

Reflow surge

Vessel reopens fast, flooding tissue with oxygenated blood.

Return to baseline

Flow overshoot settles back to normal within minutes.