Meds for Fluid and Electrolyte Imbalances Flashcards
Recall the percentage of the body’s total fluid that is inside the cells
60%
What are the 2 groups of extracellular fluids
interstitial fluid
intravascular fluid
What is the normal plasma osmolarity?
about 300 mOsm/L
Define hypotonic IV solution & its potential risk
Hypotonic = less than 300 mOsm/L
Fluid shifts into cells
Elevated ICP
Risk for cardiovascular collapse
Third spacing (edmea)
Define hypertonic solution & its potential risk
Hypertonic = greater than 300 mOsm/L
Fluid shifts out of cells
Dehydrated cells
Patients with diabetic ketoacidosis (DKA) especially at risk
Recall the goal of administering an isotonic solution
To expand the intravascular compartment
What should you watch out for when administering isotonic solution
Watch for fluid overload
–> risk for HTN or CHF
What is the most common type of isotonic IV solution
0.9% normal saline
**0.9% NS is crystalloid, meaning that it does not carry oxygen or protein
Indications for NS administration
To increase circulating volume:
shock, DKA, blood transfusions, hyponatremia, metabolic alkalosis, hypercalcemia
**watch out for hypernatremia, especially patients with renal diseases/glucocorticoids
Effects & indications for Lactated Ringer’s
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)
When should you not use Lactated Ringer’s
Patients with liver disease or in alkalosis should not receive lactated ringer’s
Recall what happens to the tonicity of 5% dextrose in water (D5W) after it is administered
D5W is isotonic in the bag –> becomes hypotonic (after dextrose is metabolized)
Indications for D5W
can be used for dehydration, hypernatremia, and hypoglycemia (restore blood glu level)
When should you not use D5W
Patients with elevated ICP, CHF, or early post-op (surgical stress may cause increase in ADH)
2 other isotonic solutions which are not often used
Hetastarch (310 mOsm/L)
Normosol (295 mOsm/L)
Recall commonly used hypotonic solution
0.45% saline (aka 1/2 NS or “half normal saline”)
Indications for hypotonic IV solution
- 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
When should you not use hypotonic solutions
Patients with burns, liver disease, or trauma
What are 2 major indications for hypertonic solutions
- Post-op patients - reduce risk of edema, stabilize BP, and regulate urine output
- Used to replace electrolyte
Discuss 3 ways surgical procedures may affect fluid balance within the body
- Big risk of edema
- Fluids are moving back and forth –> drop in blood pressure
- Kidneys not as perfused –> urine output drops
Select the most appropriate solution to administer postoperatively to improve edema, hypotension, and renal perfusion
D5 1/2 NS
**helps to minimize effects of drastic decrease in serum osmolarity (cerebral edema and hypoglycemia)
3 indications for D5 NS
- hypotonic dehydration
(possible causes: diuretics, impaired kidneys) salt loss is greater than water loss - SIADH
- Addisonian crisis
Decrease in serum osmolarity!
Discuss the pathophysiology of syndrome of inappropriate antidiuretic hormone (SIADH)
The body keeps too much water and the serum Na level drops
Contraindications for D5NS
Do not use with renal or CHF patients
(risk of fluid overload, HF, or pulmonary edema)
Indications for D5LR
Given as a fluid and electrolyte replenisher
