Meds for Fluid and Electrolyte Imbalances

Question 1

Recall the percentage of the body’s total fluid that is inside the cells

Answer 1

60%

Question 2

What are the 2 groups of extracellular fluids

Answer 2

interstitial fluid
intravascular fluid

Question 3

What is the normal plasma osmolarity?

Answer 3

about 300 mOsm/L

Question 4

Define hypotonic IV solution & its potential risk

Answer 4

Hypotonic = less than 300 mOsm/L

Fluid shifts into cells

Elevated ICP
Risk for cardiovascular collapse
Third spacing (edmea)

Question 5

Define hypertonic solution & its potential risk

Answer 5

Hypertonic = greater than 300 mOsm/L

Fluid shifts out of cells

Dehydrated cells
Patients with diabetic ketoacidosis (DKA) especially at risk

Question 6

Recall the goal of administering an isotonic solution

Answer 6

To expand the intravascular compartment

Question 7

What should you watch out for when administering isotonic solution

Answer 7

Watch for fluid overload
–> risk for HTN or CHF

Question 8

What is the most common type of isotonic IV solution

Answer 8

0.9% normal saline

**0.9% NS is crystalloid, meaning that it does not carry oxygen or protein

Question 9

Indications for NS administration

Answer 9

To increase circulating volume:
shock, DKA, blood transfusions, hyponatremia, metabolic alkalosis, hypercalcemia

**watch out for hypernatremia, especially patients with renal diseases/glucocorticoids

Question 10

Effects & indications for Lactated Ringer’s

Answer 10

Liver converts lactate into bicarbonate (base)

Given as a fluid and electrolyte replenisher (used to rapidly restore circulating blood volume in victims of burns and trauma)

Question 11

When should you not use Lactated Ringer’s

Answer 11

Patients with liver disease or in alkalosis should not receive lactated ringer’s

Question 12

Recall what happens to the tonicity of 5% dextrose in water (D5W) after it is administered

Answer 12

D5W is isotonic in the bag –> becomes hypotonic (after dextrose is metabolized)

Question 13

Indications for D5W

Answer 13

can be used for dehydration, hypernatremia, and hypoglycemia (restore blood glu level)

Question 14

When should you not use D5W

Answer 14

Patients with elevated ICP, CHF, or early post-op (surgical stress may cause increase in ADH)

Question 15

2 other isotonic solutions which are not often used

Answer 15

Hetastarch (310 mOsm/L)
Normosol (295 mOsm/L)

Question 16

Recall commonly used hypotonic solution

Answer 16

0.45% saline (aka 1/2 NS or “half normal saline”)

Question 17

Indications for hypotonic IV solution

Answer 17

• Used to replace water for hypertonic dehydration (water loss is greater than salt loss)

includes gastric fluid loss from long-term NG suctioning or intractable vomitting

• treatments for DKA

Question 18

When should you not use hypotonic solutions

Answer 18

Patients with burns, liver disease, or trauma

Question 19

What are 2 major indications for hypertonic solutions

Answer 19

1. Post-op patients - reduce risk of edema, stabilize BP, and regulate urine output
2. Used to replace electrolyte

Question 20

Discuss 3 ways surgical procedures may affect fluid balance within the body

Answer 20

• Big risk of edema
• Fluids are moving back and forth –> drop in blood pressure
• Kidneys not as perfused –> urine output drops

Question 21

Select the most appropriate solution to administer postoperatively to improve edema, hypotension, and renal perfusion

Answer 21

D5 1/2 NS

**helps to minimize effects of drastic decrease in serum osmolarity (cerebral edema and hypoglycemia)

Question 22

3 indications for D5 NS

Answer 22

1. hypotonic dehydration
   (possible causes: diuretics, impaired kidneys) salt loss is greater than water loss
2. SIADH
3. Addisonian crisis

Decrease in serum osmolarity!

Question 23

Discuss the pathophysiology of syndrome of inappropriate antidiuretic hormone (SIADH)

Answer 23

The body keeps too much water and the serum Na level drops

Question 24

Contraindications for D5NS

Answer 24

Do not use with renal or CHF patients
(risk of fluid overload, HF, or pulmonary edema)

Question 25

Indications for D5LR

Answer 25

Given as a fluid and electrolyte replenisher