EMT Course Principles of Pathophysiology (Ch. 7)

What are electrolytes

Substances which separate into dissolve particles once dissolved in water

What regulates homeostasis

The Hypothalamus and Medulla Oblongata

What’s FiO₂ ?

Fraction of inspired oxygen, or the concentration of oxygen in the air we breathe.

What things can interrupt epinephrine or norepinephrine? What effect can this have?

Addison’s Disease which reduces the production and medications like Beta Blockers which decrease the effects of epinephrine or norepinephrine.

These can impair compensation because they decrease the activation of the sympathetic nervous system.

What is a patent airway?

An open airway

What are some things which can interrupt having a patent airway?

1. Choking

2. Infection (such as a child with Croup)

3. Trauma

4. Burns which can cause the soft tissue of the larynx to swell

What is Tidal Volume?

The volume of air moved in one in and out cycle of breathing.

What is the respiratory rate

Breaths per minute

What is the minute volume?

The amount of air that gets in and out of the lungs in a minute

What is the air which doesn’t reach gas exchange called? Like the air that only makes it in between the mouth and the alveoli?

Dead Air Space

What are the causes of respiratory dysfunction?

1. Medulla Oblongata Disruption (can be due to drugs and intracranial hypertension, as well as typical causes for brain dysfunction)

2. Disruption of Pressure between the lungs and chest wall. Requires negative pressure to stick and function.

3. Disruption of Lung Tissue. (also includes bad alveoli exchange). Leads to hypoxia and hypercapnia.

What is the area between the lungs and the chest called?

Pleural Space

What is the force pulling water into the blood stream? Where does it come from?

It’s Plasma Oncotic Pressure, and it comes from the large proteins in the plasma.

What pressure pushes fluids into cells?

Hydrostatic pressure, or water pressure, that is created when the heart beats.

What is something that can lead to disruption of water balance?

Liver failure. Since the liver makes Albumin, a plasma protein, liver failure can lead to water accumulating in body cells.

Blood Dysfunction

1. Bleeding

2. Dehydration

3. Anemia

4. Liver failure → lack of Albumin → water accumulation in cells → decrease in volume of the blood

What are the sensors in blood vessels? What do they do?

Stretch receptors, which can detect the internal pressure and signal the brain.

What’s notable about child compensation (2 things)? What’s a byproduct of this and how do we tell if this compensation has occurerd?

1. Children’s vasoconstriction is strong enough to maintain pressure with severe loss of volume. Because of this pressure cannot be used to recognize hypovolemia.

2. Children have less heart muscle, so they will rely. more heavily on heart rate for compensation.

Since this also causes shunting, or the redirection of blood flow from it’s usual path, away from the skin. We can detect this by pressing down on the fingernail bed—or palm for really small patients—and see how quickly the color gets restored.

And we can also look at the heart rate.

Children are also more prone to mental status changes due to their brain taking up more relatively to them.

Skin is thinner so it’s important to cover with blankets to prevent hypothermia.

Children also deteriorate very quickly after compensation fails.

What’s pallor

Pale appearance. Consequence of shock.

What are some types of blood pressure dysfunction?

1. Loss of tone, blood vessels can’t control their diameter. Can be due to:

   1. Nervous system injury

   2. Infection

   3. Allergic Reaction

2. Excessive permeability. Can lead to pulmonary edema.

   1. Sepsis

   2. High altitude

   3. Disease

3. Hypertension

4. Interruptions to Compensation such as due to spinal injury.

What’s the force the heart needs to pump against called?

This is called Systemic Vascular Resistance or SVR. Raised by hypertension.

Stroke Volume and average.

How much blood is ejected per squeeze. Average 70 mL

Preload

How much blood is returned to heart prior to each contraction

Contractility

Strength of heart to contract

Afterload

The force the left ventricle needs to overcome to eject blood through the aorta.

Cardiac Output

The per minute total volume the heart pumps.

What are the types of shock

1. Hypovolemic Shock. Lack of volume.

2. Distributive Shock. Loss of blood vessel tone.

3. Cardiogenic Shock. Heart fails to pump blood.

4. Obstructive Shock. Blood is physically presented from moving.

Compensated Shock

Steps which the body takes to compensate in response to shock.

Brain activates SNS, does everything we’ve talked abt along w kidney stops eliminating fluid, bone marrow produces more RBCs

What are physical symptoms of compensated shock

1. Change in mental status

2. Change in heart and breathing rate

3. Delayed capillary refill time (due to shunting!)

4. Pale skin

5. Sweat

Compensation can sometimes be prevented by whatever caused the shock in the first place. Obviously for MI heart rate won’t increase.

Decompensated Shock

Refers to when compensation for shock fails

Irreversible Shock

When organs die due to hypoperfusion

What are the three places water is distributed in the body? Percentages as well.

70% Intracellular

5% Intravascular

25% Interstitial (water between cells and blood vessels)

Edema

Swelling associated with movement of water. Seen in dependent parts of the body.

What are dependent parts of the body

Parts of the body which are more dependent on gravity

What are the three types of endocrine dysfunction?

1. Too many hormones. Grave’s Disease leading to thyroid overproduction.

2. Too little hormones. Type 1 Diabetes

3. Adrenal insufficiency. Typically caused by medication sometimes disease though.

Hypersensitivity

Allergic Reaction. Histamine can cause edema and narrow airways. Other chemicals can dilate blood vessels leading to distributive shock.

EMT Treatment of Shock

Nonrebreather mask with 100% oxygen if the patient can breathe, if they have a very low or no breathing on their own then use a BVM (Bag Valve Mask)

Children one breath every 2-3 seconds

Adult every 5-6 seconds

Why is supine used for shock? When is it not used?

Supine is used to make it so where the blood doesn’t have to fight gravity to perfuse the brain.

If the patient is uncomfortable in the supine position (such as with breathing problems).

Why blanket

Because the shunting of blood away from the surface of skin will lead it to being cold, triggering the temperature sensors in the body to think the body is freezing leading to shivering which wastes energy.