What shock is
Shock is inadequate perfusion. Perfusion is blood reaching the cells with oxygen and taking waste away. To perfuse you need three things: a working pump (the heart), enough fluid (blood), and a container of the right size (the blood vessels). Break any one of those and the cells begin to starve. Every type of shock is one of those three failing.
How the body fights back, and why that creates the signs
The moment perfusion falls, the nervous system floods the body with adrenaline. Everything you see in early shock is that response:
- Fast pulse. The heart beats faster to move what blood is left.
- Cool, pale, clammy skin. The vessels in the skin clamp down to send blood inward to the brain and heart. Cold skin is the body's triage decision.
- Fast breathing. The body tries to load more oxygen onto the blood it has.
- Anxiety, restlessness, thirst. The brain is the first organ to notice it is being short-changed.
- Normal blood pressure. Because the compensation is working. This is the trap.
This stage is compensated shock: the body is holding pressure by effort. When the effort fails, blood pressure falls, the mental status drops, the pulse goes weak and thready, and the skin goes mottled. That is decompensated shock, and the window to fix it is closing. Past that is irreversible shock: organs have been without oxygen long enough that they will not recover.
A fast pulse with cool, pale, clammy skin is shock until proven otherwise, and a normal blood pressure does not prove otherwise.
The four types
| Type | Which part failed | Examples | The tell |
|---|---|---|---|
| Hypovolemic | Fluid: not enough blood or plasma | Bleeding, severe burns, vomiting and diarrhea, dehydration | The classic picture: fast weak pulse, cold clammy skin, an obvious or hidden source of loss |
| Cardiogenic | Pump: the heart cannot move the blood | Heart attack, severe rhythm problems | Chest pain or cardiac history, often fluid in the lungs, may have a slow or irregular pulse |
| Distributive | Container: vessels open too wide | Anaphylaxis, sepsis, spinal cord injury (neurogenic) | Warm, flushed skin at first in anaphylaxis and sepsis; in neurogenic shock, a slow pulse with low pressure and warm dry skin below the injury |
| Obstructive | Flow is blocked mechanically | Tension pneumothorax, cardiac tamponade, massive pulmonary embolism | Distended neck veins, breathing difficulty, collapse out of proportion to the story |
Notice that distributive shock breaks the pattern: the skin can be warm because the vessels are wide open rather than clamped. If you only memorized "cold and clammy" you will miss anaphylaxis and sepsis. If you learned the mechanism, you will not.
What an EMT does about it
- Recognize it early, from the pulse and skin, not the cuff.
- Fix what you can fix. Stop the bleeding: direct pressure, wound packing, tourniquet. Open the airway. Give oxygen. Epinephrine for anaphylaxis. Manage the rhythm and pain in a cardiac patient within your protocols.
- Keep them warm. A cold patient clots poorly and the heart works worse. Blankets are a treatment.
- Position. Lying flat, unless breathing is the problem; then let them sit up.
- Move. Rapid transport to the right hospital, with early notification. The definitive treatment for most shock, blood or surgery or a catheter lab, is not on the ambulance.
- Reassess every five minutes. The trend tells you whether you are winning.
Anchors that stick
- Pump, fluid, container. Every shock is one of the three.
- Cold skin is a decision: the body chose the brain over the fingers.
- Pressure is the last thing to fall.
- Warm and in shock means the container opened: think allergy, infection, spine.
Questions people ask
What are the early signs of shock?
A fast pulse and cool, pale, clammy skin, often with anxiety, restlessness, thirst and faster breathing, while the blood pressure is still normal. Those are the body's compensation. Falling blood pressure is a late sign.
What are the four types of shock?
Hypovolemic (not enough fluid, such as bleeding), cardiogenic (the heart cannot pump), distributive (the vessels open too wide: anaphylaxis, sepsis, neurogenic), and obstructive (flow is mechanically blocked: tension pneumothorax, tamponade, pulmonary embolism).
How does an EMT treat shock?
Recognize it early, stop bleeding, manage the airway and give oxygen, treat the specific cause within protocol (for example epinephrine for anaphylaxis), keep the patient warm, position them appropriately, transport rapidly with early hospital notification, and reassess every five minutes.