Heart, blood pressure and stroke in Casualties: Unknown

Heart rate basics

A healthy heart sits around 70 bpm and adjusts itself to hold blood pressure near 120/80. Pain, adrenaline, low stamina, heat, thick blood and fibrillation push it up; opiates and cold pull it down. Above 200 bpm fibrillation starts. Below 20 bpm the heart stops.

Fibrillation

Fibrillation is an abnormal rhythm that climbs about 1% per second while any cause is present, and 4% per second above 280 bpm (since demo 6.1). Each 1% adds 1 bpm and lowers breathing. At 60% the injury alarm plays and you hear your heartbeat outside the panel; at 100% the heart stops.

Moodles: arrhythmia above 15%, ventricular tachycardia above 50%, ventricular fibrillation above 75%. A shock resets fibrillation to 0 but it comes back if the cause remains. Amiodarone lowers it over time. Touching a coil also resets it.

Defibrillators: AED vs manual

Use either on the upper torso. Both start a minigame. Always check the battery first: players often find their AED empty at the worst moment. A wrench takes batteries out.

The rule from the community wiki: the right power is twice the fibrillation percentage. Each joule off costs 2.5% success, and 40 J or more off never works. The device shows an estimated range that narrows with INT: about 140 J wide at INT 10, 90 J at INT 15, 0 to 10 J at INT 23 or more. Restart the minigame to reroll the estimate and intersect the ranges. Community wiki

Cardiac arrest

A flat ECG, 0 bpm and the dying drone. Without circulation, brain health falls fast. If you are still conscious:

1. Put on an auto-pump: it pumps blood when pressure gets low and keeps oxygen moving.
2. Shock with a defibrillator. Any power works for arrest; use low power to save battery. Each successful shock has a 20% chance to restart the heart.
3. Or take epinephrine: each tick has a 3% chance to restart the heart (at 50% fibrillation). Injected epinephrine lasts 6 ticks per ml, drunk 1. Too much (over 240 ticks) makes fibrillation worse.
4. Once restarted, shock again if needed to clear the fibrillation, then fix the cause.

Restarting a stopped heart unlocks Dead Man Walking, one of the rarest achievements at about 1.5% of players.

Blood pressure

What moves pressure: blood volume (the biggest factor), viscosity, heart rate, temperature (3/2 per °C away from 37), thirst above 100 or below 40, weight, opiates (lower), sepsis (lower), vasopressin (higher) and sodium nitroprusside (lower).

Stroke

A stroke is bleeding in the brain. It starts with a 2% chance per second while systolic pressure is over 180, or rarely from eating a browncap, then grows by about 8 per minute. Each point costs blood and brain health.

• Above 20: stuttering speech.
• Up to about 50: the left arm weakens, then becomes unusable; you lose vision behind you.
• Above 50: the health panel button flashes. Above 70: the moodle finally appears.
• Above 90: fibrillation is forced.

Fix: any amount of braingrow clears a stroke over 100 seconds. Procoagulant reduces it fast. A neural booster, mindwipe or last stand sets it to 0. Then bring your pressure down so it does not happen again.

Pulmonary embolism

With blood viscosity above 90 you can develop a pulmonary embolism, which damages the thorax muscle until lung failure in about 2 minutes 40 seconds from full health. A bruise kit or L.R.D. buys time. It ends once viscosity drops below 50. In Unchipped you only notice it from dialogue or the fur on your chest.