Sodium Worksheet

What are the components of the BMP/Chem7?

Na / Cl/ BUN

K / HCO₃ / creatinine ——> glucose

What are the normal values of the BMP?

140 / 104/ 12/

4.3 / 24 / 0.8

What does Na measure

Salt in blood

What does Cl measure?

Control fluid balance

What does BUN (blood urea nitrogen) measure?

Checks kidney function

What does K measure

How muscles and heart work

What does HCO₃ measure

Shows acid/base balace

What does glucose measure

Sugar in blood

What does hyponatremia mean?

You have too much water, and low levels of sodium (120 mEq/L)

What does hypernatremia mean?

You have too little/not enough water, and an abnormally high level of sodium in the blood

What is Antidiuretic Hormone?

Also known as vasopressin

Where is ADH made

A hormone made in the hypothalamus of the brain

What are the functions of ADH?

1. To restrict loss of water in urine

2. To cause vasoconstriction in order to raise the blood pressure

What does ADH do in the kidney?

Causes increased aquaporin channels in collecting duct cells so water can reabsorb out of the urinary filtrate and back into the blood stream

ADH is secreted by the hypothalamus in response to

Increased osmolality and decreased blood volume as detected at the hypothalamus.

What is the action for ADH?

Fast action at the cells to retain water and decrease diuresis

What does serum Na⁺ concentration tell us about the total amount of sodium in the body?

Reflects total body water; water follows sodium around the body, wherever there is sodium, water will also be there

What does the serum sodium tell us?

The amount that has been sent to the serum compartment. It does not reflect the total amount of sodium in the body.

Because water moves freely across all body compartments, and water always follows sodium

A change in the serum docium reflects the total amount of water in the body

What does it mean if the serum sodium is low?

Hyponatremia- the total body water is in excess

What does it mean if the serum sodium is high?

Hypernatremia- the total body water is deficient

Too little water relative to salt

Hypernatremia

Too much salt + water

Edema

Too little salt

Volume depletion

Too much water relative to salt.

Hyponatremia

How would you fix hyponatremia?

1. Stop drinking water

2. Stop administering water

3. Increase diuresis

4. Turn off ADH with medications

How would you fix hypernatreia?

1. Drink water

2. Administer water

3. Decrease diuresis

4. Turn off ADH with medications

How would you fix edema

1. Decrease salt intake

2. Administer a diuretic —> pee out more salt

3. Increase pain water intake

How would you fix volume depletion?

1. Increase salt intake and water

2. Administer salt in the form of 0.9% normal saline

What do you see in volume depletion?

“bag of salt water” is too small, this will manifest as hypotension, poor skin turgor

How will your ADH levels manifest in volume depletion?

ADH levels will be high due to volume depletion, and low blood pressure (as detected in the aortic arch baroreceptors and reported to the hypothalamus.

How does hypoosmolality affect ADH levels?

Hypoosmolality decreases ADH, but volume depletion overrides osmolality as a stimulus for ADH release

Why would you see high sodium?

If the patient lost water (by not drinking for hours), but didn’t lose salt (so blood became more concentrated/saltier)

Why would BP be normal even tho the PT is dehydrated?

Because the water that the pt does have is staying with the sodium in their blood vessels, keeping the blood volume enough to maintain BP

What is a “free water deficit”?

Not enough total body water - the body is “dry” but total sodium amount is ok

When blood sodium is high, what happens to ADH?

It increases

What is the difference between dehydration and volume depletion?

• Dehydration = not enough water (free water loss).

• Volume depletion = not enough blood volume (water + salt loss).
  (Mr. Smith is dehydrated, but not volume depleted.)

What signs in Mr. Smith’s physical exam show dehydration?

Dry tongue, hot dry skin, good skin turgor, fever