Foundations

Water and charged minerals run every nerve, muscle, and heartbeat — and small derangements in either direction can stop the heart.

Four ways plasma pH goes wrong, two organs racing to fix it — and the stepwise ABG read that tells you which patient is in trouble.

Whatever the cause — lost volume, failed pump, lost vessel tone, or blocked flow — shock is the same event: tissues starving for oxygen while the vital signs still look deceptively normal.

A dysregulated response to infection that injures the body’s own organs — it contributes to 1 in 3 hospital deaths, and recognition in the first hour drives survival.

One nonspecific defence that produces every local sign a nurse inspects, every marker a nurse interprets, and — if it fails to switch off — the fibrosis and the chronic disease that kill three of every five people.

The vocabulary layer for the rest of the course: how cells adapt to stress (atrophy, hypertrophy, hyperplasia, metaplasia), how some adaptations slide toward cancer (dysplasia, carcinoma in situ), and how injured cells die — by inflammatory necrosis or silent apoptosis.

How a harmful stimulus becomes the experience of pain — transduction, transmission, perception and modulation — and how nurses measure it: self-report first, a validated behavior tool when the patient cannot speak, reassessment timed to the drug and route, and sedation checks because sedation comes before opioid respiratory depression.

Heat illness runs from heat cramps and heat exhaustion — water and salt loss with heavy sweating — to heat stroke, where thermoregulation fails and a high core temperature injures the brain, kidneys, liver, muscle and clotting system. Central nervous system dysfunction marks heat stroke. Call 911 and cool immediately — ice-water immersion is fastest — without waiting for transport; antipyretics and dantrolene do not help. Prevention, hydration without over-drinking, and medication review protect those at risk.

Hypothermia is a core temperature below 35 °C: shivering and clumsiness give way to confusion, bradycardia, dysrhythmias and coma as the body cools. Measure core temperature with a low-reading probe, handle the patient gently, remove wet clothing and rewarm the trunk — passive, then active external, then internal or extracorporeal methods by severity — and start CPR even if the person appears dead. Frostbite is tissue freezing: rewarm rapidly in 37–39 °C water only when refreezing will not happen, never rub, give analgesia, update tetanus, and refer deep injury promptly.

Drowning is the process of respiratory impairment from submersion or immersion in liquid; it can be fatal or nonfatal. Hypoxia is the main insult, so rescue focuses on airway and breathing first — 5 initial rescue breaths before chest compressions. The cervical spine is immobilized only after trauma such as diving, the Heimlich maneuver is not used, and hypothermia is managed alongside. Well patients are observed for 4 to 8 hours; rare, fulminant pulmonary edema can develop within 12 hours. Most drowning is preventable.

Mammal bites inject mouth flora into tissue: cat bites are deep punctures with the highest infection rate, dog bites crush and tear, and a human "fight bite" over a knuckle can seed the joint. Care is irrigation, amoxicillin-clavulanate for bites that break the skin, tetanus by wound type and vaccine history, and rabies postexposure prophylaxis when indicated. Venomous snakebites need emergency care — no tourniquet, ice, cutting or suction — with antivenom for progressive envenomation. Black widow venom causes pain and cramping; brown recluse venom causes necrosis and, in children, hemolysis.