Intraoperative Hemostasis: Bleeding Control Simulator

Vessel Setup

Vessel diameter 3.0 mm

Interventions

Active bleeding — apply an intervention.

Patient Vitals

Hemorrhagic shock class: I

Blood loss

0 mL

Bleed rate

0 mL/min

Heart rate

75 bpm

Systolic BP

120 mmHg

How it works

Bleed rate follows a simplified Poiseuille relation: flow through a vessel scales with the fourth power of radius and with the driving pressure. Here we approximate cross-sectional scaling with vessel diameter², scaled by the patient's current blood pressure (a falling BP itself slows bleeding — a real physiological feedback loop):

Q ≈ k · d² · (BP / BP₀) · (1 − tamponade)

Direct pressure builds a tamponade factor toward 1.0 the longer it's held, throttling flow but reversing if released. Electrocautery reliably seals small vessels (real electrosurgery denatures collagen to seal ≲3 mm vessels) but is unreliable on larger ones — attempting it on a wide vessel here has a real chance of failing and causing a brief re-bleed spike. A clamp stops flow immediately but is temporary; ligation (simulated suturing, needs ~3 s uninterrupted while clamped) seals the vessel permanently.

Vitals follow a simplified ATLS hemorrhagic shock classification driven by % of ~5,000 mL total blood volume lost:

Class I   <15%   HR <100   BP normal
Class II  15–30%  HR 100–120 BP low-normal
Class III 30–40%  HR 120–140 BP reduced
Class IV  >40%   HR >140   BP critically low

Every liter of unstopped hemorrhage pushes the patient one class further — the same table trauma teams use to decide when to transfuse.

Active bleeding Tissue bed Surgical clamp

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