emt 29 30 31

3 components of circulatory system

Heart (pump), vessels (pipes), blood (fluid)

Arteries function

Carry oxygenated blood AWAY from heart (high pressure)

Veins function

Return deoxygenated blood TO heart (low pressure, valves)

Capillaries function

Exchange oxygen, nutrients, waste with cellls

Perfusion vs hypoperfusion

• Perfusion = normal oxygen delivery

• Hypoperfusion = inadequate → shock

Definition of shock

Inadequate perfusion → cells don’t get oxygen → organ failure

4 causes of shock

1. Volume loss

2. Pump failure

3. Vessel dilation

4. Obstruction

Hypovolemic shock

Loss of blood or fluid → ↓ volume

Hemorrhagic shock

Specific type of hypovolemic shock from blood loss

Absolute vs relative hypovolemia

• Absolute = Actual loss of blood or fluid from the body

• Relative = Blood is still in the body, BUT vessels get bigger or fluid shifts out

Cardiogenic shock

Heart fails to pump effectively (MI, CHF)

Distributive shock

Blood vessels lose tone and dilate → pressure drops → blood isn’t effectively delivered to organs

Anaphylactic shock

Severe allergic reaction → vasodilation + permeability

Neurogenic shock

Shock caused by loss of nervous system control of blood vessels (usually from spinal cord injury)

• Low blood pressure (hypotension)

• Slow heart rate (bradycardia)

• Warm, dry skin (no sweating below injury)

Septic shock

A type of distributive shock caused by a severe infection → body-wide inflammatory response → vasodilation + leaky vessels

Obstructive shock

Shock caused by a physical blockage that prevents blood from moving through the heart/lungs (PE, tamponade, tension pneumo)

Which cells die fastest?

Brain + heart (minutes)

What happens during compensation?

Body tries to maintain perfusion

3 compensation methods

• Fluid retention (kidneys)

• Vasoconstriction

• ↑ HR + ↑ RR

What triggers compensation?

Baroreceptors + chemoreceptors

Fight-or-flight response effect

Epinephrine → ↑ HR, vasoconstriction, sweating

Compensated shock

Early stage of shock where the body is still maintaining blood pressure using compensation.

If BP is normal BUT:

• fast HR

• fast RR

• pale skin

Decompensated shock

The stage of shock where the body’s compensation fails → it can no longer maintain blood pressure or perfusion.

• HR may drop or become weak

• RR becomes irregular/slow

• BP ↓

Why compensation shock fails

Body runs out of oxygen + energy

Late signs of shock

• Hypotension

• Altered LOC

• Cyanosis

• Weak/slow pulse

Why skin is pale/cool in shock

Vasoconstriction shunts blood to core

Why nausea occurs in shock

Blood diverted from GI system

Narrowing pulse pressure meaning

Vasoconstriction → worsening shock

Pediatric shock difference

for kids:

• BP stays NORMAL until VERY late

• tachycardia

• pale skin

• delayed cap refill

• tachypnea

Best early indicator of shock

Vital sign trends (HR ↑, RR ↑)

Tachycardia (increased heart rate)

Arterial bleeding

Bright red, spurting, severe

Venous bleeding

Dark red, steady

Capillary bleeding

Slow ooze

Massive hemorrhage definition

Rapid, life-threatening blood loss

Junctional bleeding locations

Neck, armpit (axilla), groin

Why junctional bleeding is dangerous

Involves major vessels and cannot be easily controlled with a tourniquet

Bleeding control order

1. Direct pressure

2. Wound packing

3. Hemostatic agents

4. Tourniquet

How direct pressure works

Compresses vessels → allows clotting

Key rule with dressings

DON’T remove once applied

When to use wound packing

Deep wounds/junctional areas

Key technique for wound packing

Pack until FULL → then apply pressure

What hemostatic agents do

Speed up clotting

STILL need direct pressure

When to use tourniquet

Severe extremity bleeding not controlled

Improvised tourniquet rule

Must be wide (≥2 inches), never rope/wire

Elevation purpose

↓ blood pressure in limb

Cold application purpose

Vasoconstriction + ↓ bleeding

Head injury bleeding what u dont do vs what u do

DO NOT stop fluid from ears/nose

DO:

• Let fluid drain freely

• Place a loose sterile dressing to catch it

• DO NOT apply pressure

Nosebleed treatment

Lean forward + pinch nostrils

5 core treatments for shock

• Rapid transport

• Oxygen

• Control bleeding

• Keep warm

• Supine

Signs of internal bleeding

• Bruising

• Tender abdomen

• Vomiting blood

• Blood in stool

• Shock signs

Best clue for internal bleeding

Mechanism of injury

What are soft tissues?

Skin, fat, muscles, vessels, nerves, connective tissue, glands

3 layers of skin

Epidermis → outer, no blood vessels → less bleeding

Dermis → blood vessels + nerves → pain + bleeding

Subcutaneous → fat layer → insulation + shock absorption

Epidermis characteristics

No blood vessels or nerves → superficial injuries less severe

Why is dermis injury serious?

Dermis has blood vessels + nerves → bleeding + pain + infection risk

Subcutaneous layer function

Insulation + shock absorption

Closed wound definition

Skin intact, internal damage

Types of closed wounds

Contusion, hematoma, crush injury, blast injury

Contusion

A closed soft-tissue injury where the skin is intact but underlying blood vessels are damaged, causing bleeding into the tissues

• Assess ABCs

• Treat for possible internal injury/shock if MOI is significant

• Cold pack (not directly on skin)

• Monitor

Why swelling happens

Blood + inflammation

Hematoma

A localized collection of blood under the skin or in tissue from a damaged blood vessel (usually a closed injury).

• ABCs, assess MOI

• Consider internal injury/shock if large or high-risk location

• Cold pack (not directly on skin)

• Splint if associated with extremity injury

• Monitor

Key difference contusion vs hematoma

Contusion = small vessel bleeding (flat bruise)

Hematoma = larger vessel bleeding (raised blood collection)ore severe bleeding

Crush injury

Injury caused by strong compressive force that damages internal tissues/organs (with or without breaking the skin).

Why crush injuries are dangerous

Internal bleeding + organ rupture

Closed wound care priorities

• ABCs

• Treat for shock

• Splint

• Cold packs

• Rapid transport

Open wound definition

Skin broken → infection risk

Abrasion

A superficial open wound where the top layer of skin is scraped off

Scrape (high infection risk, painful)

Laceration

A cut or tear in the skin caused by a sharp or blunt object (can damage vessels/tendons)

Puncture wound

Deep penetration → small outside, severe inside

Why punctures are dangerous

Internal bleeding + infection + hidden damage

Avulsion

A wound where skin or tissue is torn away (partially or completely)

Rule for impaled objects

DO NOT remove

When can you remove impaled object in cheek?

If it passes through AND both ends visible

Steps for open wound care

1. Expose

2. Control bleeding

3. Prevent contamination

4. Dress + bandage

5. Treat shock

Always check PMS (pulse, motor, sensation) distal to injury

Biggest mistake with wounds

Focusing on gross wound → missing ABCs

Dressing

Covers wound (sterile)

Bandage

Holds dressing in place

Pressure dressing

Tight bandage to control bleeding

Occlusive dressing

A dressing that creates an airtight seal over a wound (chest, neck, abdomen)

Universal dressing

Large bulky dressing

3 ways to classify burns

• Agent/source

• Depth

• Severity

Burn agents

Thermal, chemical, electrical, radiation, light

Superficial burn

Epidermis only → red, painful, no blisters

Partial thickness burn

Epidermis + dermis → blisters, very painful

Full thickness burn

All layers → charred/white, NO pain (nerve damage)

High-risk burn locations

Face, hands, feet, genitalia, joints

Why circumferential burns dangerous

(Burns that go all the way around a body part (arm, leg, chest, etc.))

Restrict circulation/breathing

Rule of nines

Body divided into 9% sections (adult)

Rule of palm

Patient palm = 1% body surface

Burns requiring burn center

10% partial thickness

ANY full thickness

Face/hands/feet/genitals

Electrical

Inhalation

First step thermal burn

Stop burning process

What NOT to do for burns

• No ice

• No ointments

• Don’t pop blisters

Key treatment for burns

• Dry sterile dressing

• Oxygen

• Treat shock

Signs of airway burn

• Hoarse voice

• Soot

• Burned hair

• Stridor

Why airway burns dangerous

Swelling → delayed airway closure

Main treatment for chemical burns

Flush with water (≥20 min)

Do NOT use neutralizers (like vinegar/baking soda)

Exception chemical burns (dry chemicals)

Brush off first, THEN flush

Why alkali burns worse

Alkalis penetrate deeper and keep destroying tissue

Why electrical injuries dangerous

Small outside, massive internal damage

Electrical injury signs

• Entry/exit wounds

• Arrhythmias

• paralysis

• fractures