Fluid and Electrolytes Flashcards
Which has more water, the intracellular space or the extracellular space?
Intracellular volume (40%) -Extracellular volume has 20%
What is extracellular volume (ECV) made up of?
Interstitial fluid
Plasma
3:1 ratio of IF to plasma
What electrolytes are in ECV?
Na
Cl
HCO3
What electrolytes are in ICV?
K, PO4, SO4
What is the most important osmotically active colloid in ECV?
Albumin
4 g/L in serum vs. 1 g/L in serum
What is the target concentration of Na in the body?
140 mg/dL
What is the target concentration of Cl in the body?
100 mg/dL
What is the target concentration of K in the body?
4 mg/dL
What is the target concentration of Alb in the body?
4 g/L
What is the 4-2-1 rule?
- First 10 kg: 40 cc
- Next 10 kg: 20 cc
- I cc for every kg after that
What does D5 mean as it pertains to fluids?
5 g of dextrose per 100 ml of fluid
What does normal mean as it pertains to fluids?
- Refers to osmolarity
- We want same in fluid as in body
What is third spacing?
Leaking of fluid into interstitial space between skin and fascia; normally this area is not filled with fluid.
What is ideal urinary output?
1 cc/kg/hr
Hemolysis can cause false high readings of what electrolyte?
K
What situations can cause hypernatremia?
When we lose water without salt:
- Burns
- Fever
- Hyperventilation
What situations can cause hyponatremia?
When we lose water with salt:
- Diuretics
- NGT
- Hypoproteinism (cirrhosis, nephrotic syndrome, malnutrition)
What conditions can cause hypokalemia?
Vomiting, diarrhea
NGT
Renal losses
Prolonged NPO
Why is vomiting so bad for potassium losses?
While we are losing K from vomiting, our kidneys excrete extra K to hold on to H+ and Na+
What is the primary danger of having low potassium?
Cardiac arrhythmias
What are usual signs if hypokalemia?
Weakness
Ileus
What will an EKG show in hypokalemia?
Flattened T waves
Low magnesium can cause what other electrolyte change?
Hypokalemia
Most important electrolyte imbalance to consider in surgery patients?
Hypokalemia
What are some effects of hyperkalemia?
Spiked T-waves
Arrhythmias
Sudden death!
What are four treatments for hyperkalemia?
IV calcium gluconate
Glucose, insulin, sodium bicarbonate
Potassium-binding resins
Dialysis
How does calcium gluconate treat hyperkalemia?
Antagonizes effects at cell membrane
Works in seconds to minutes
How do glucose, insulin, and sodium bicarbonate treat hyperkalemia?
Move K back into cells
Works in 30-60 mins
How do potassium binding resins work?
Bind and hasten excretion of K into colon
Works in 1-6 hours (faster rectally)
Where is most calcium found?
Bones
Where is calcium that’s not in bones found?
Bound to albumin
Where is calcium absorbed?
Duodenum
What does calcium do?
- Muscle contractions
- Nerve conduction
- Coagulation
What are the usual causes of hypercalcemia?
Parathyroid problem
Malignancy
What are the symptoms of hypercalcemia?
- Muscle weakness
- Fatigue
- Depression
- Anorexia
- Arrhythmias
Treatment for hypercalcemia?
Lasix
Vigorous NS
Calcitonin
Bisphosphonates
What are symptoms of hypocalcemia?
- Paresthesias
- Muscle spasms
- Tetany
What are usual causes of hypocalcemia?
Parathyroid surgery
Pancreatitis
Low albumin
What is often the hidden reason why other electrolytes can’t be normalized?
Low Mg
-Target is 2.0
When is PO4 often high?
In renal failure
What are indications for dialysis?
- Acidosis
- Uremia w/ symptoms
- Hyperkalemia
- Volume
