Fluid and Electrolytes 2 Flashcards
What are a major cause of electrolyte abnormalities?
Diuretics
What are two conditions that no abnormality exists so there is no need to treat?
Pseudohyperkalemia from RBC lyses
Hypocalcemia from hypoalbumenia
What is used for K+ replacement?
No bolus of IV doses
Infusion rate should not exceed 10-20 Eq/hr
Usually have limitations on concentration for peripheral infusion (max 60 mEq/L)
When should IV calcium be used?
If cardiac sx exist for hyperkalemia or hypermagnesemia
When do low serum concentrations of K+, Mg2+, and PO4+?
Low serum concentrations can occur with refeeding syndrome, add higher than standard doses to PN and glucose containing IV solution if patient at risk
When do high serum concentrations of K+, Mg2+, and PO4+?
High serum concentrations can occur in renal failure, use reduced doses in PN and IV fluids
What occurs when calcium and phosphorous are mixed PN?
- Increased risk for calcium-phosphorous precipitation if PN mixed with
- Sodium bicarbonate when treating hyperkalemia
- Infusions of calcium or phosphorous when treating deficiencies
What are the laboratory electrolyte tests?
Chem 7
Chem 10
Electrolyte panel
Need to order ionized calcium seperate
What drugs lead to hyperkalemia?
K+ sparing diuretics
ACE-I, NSAIDS
Beta-antagonists
Not drug related but be aware of the possibility of pseudohyperkalemia (lysis of RBC during collection)
What drugs lead to hypokalemia?
Diuretics (except K+ sparing)
Insulin, refeeding syndrome, treatment of DKA
Beta-agonist, glucocorticoids
Amphotericin B, aminoglycosides
What drugs lead to hypermagnesia?
Lithium
What drugs lead to hypomagnesemia?
Diuretics Amphotericin B, aminoglycosides Cyclosporin, alcohol Digoxin Laxative abuse Refeeding syndrome
What drugs lead to hypercalcemia?
Thiazide diuretics (but not loop or K+ sparing) Lithium, Vitamin A and D toxicity, calcium
What drugs lead to hypocalcemia?
Loop diuretics
Oral Phosphorus
Phenytoin, barbituates
Vitamin D deficiency
What drugs lead to hyperphosphatemia?
Phosphate- containing enemas
IV phosphorous to treat hypercalcemia
What drugs lead to hypophosphatemia?
Diuretics
Insulin, dextrose, refeeding syndrome, treatment of DKA
Sucralfate, antacids, calcium salts
What type of symptoms and treatment is associated with electrolyte abnormalities with a slow and chronic onset?
Electrolyte abnormalities with a slow and chronic onset usually have less severe symptoms and can be gradually corrected
What type of symptoms and treatment is associated with electrolyte abnormalities with an acute onset?
Electrolyte abnormalities with an acute onset may have more severe symptoms and should be treated more aggressively
What are the treatment goals of electrolyte abnormalities?
- Treat or prevent severe life-threatening signs and symptoms
- Improve or correct serum electrolyte concentration to within normal values
- Do not overcorrect
- Avoid undesirable effects of treatment
- Correct cause for abnormality
- Factors to consider: Presence and severity of symptoms, Acuteness of onset
What is the most abundant cation in the ICF?
Potassium
Is the serum K+ a good measure of total body potassium?
Intracellular; serum K+ not good measure of total body potassium
Clinical manifestations correlate well with serum potassium
What are the cardiac abnormalities associated with hyperkalemia?
Ventricular fibrillation
Asystole
ECG: peaked T waves
**Life threatening
What are the muscle abnormalities associated with hyperkalemia?
Weakness
Paralysis
What is hyperkalemia defined as?
Defined as serum K+ >5mEq/L
What are the causes of hyperkalemia?
Increased potassium intake (be aware of potassium sparing diuretics)
Decreased potassium excretion
Potassium release from intracellular space
What are the treatment goals of hyperkalemia?
Antagonize adverse cardiac effects (only needs to be done if having cardiac effects, needs to be done first)
Reverse other sx
Return serum concentrations to normal
What are the treatment approaches for hyperkalemia?
Antagonism of K+ if cardiac abnormalities exist (only if cardiac effects are present)
Promote intracellular redistribution
Remove K+ from the body
If cardiac effects are present (peaked T-waves, widened QRS) what are the treatment options?
IV calcium gluconate
IV calcium gluconate
- Only restores normal conduction of heart
- Does not reduce or redistribute serum K+
- Onset 1-2 minutes; duration 10-30 minutes
- May need to repeat dose if symptoms return
- Calcium gluconate 10% (1 ampule) over 5-10 minutes, repeat every 30-60 minutes until ECG normalizes
What is the first line therapy of hyperkalemia treament for the correction of intracellular redistribution as long as acidosis is not present?
Regular insulin
5-10 units IV or SubQ
Onset 30 minutes; duration 2-6 hours
If not hyperglycemic, give dextrose D10W, 1L over 1-2 hours D50W, 50ml over minutes Insulin promotes cellular uptake of K+ Glucose enhances exogenous insulin release and prevents hypoglycemia
What is the second line therapy for hyperkalemia treatment for the correction of intracellular redistribution?
Albuterol (B2-agonist) is second line therapy
Use if patient unresponsive to insulin/glucose after 30-60 minutes
10-20mg (high dose) nebulized over 10 minutes
Onset 30 min; duration 1-2 hours
What is the treatment used for hyperkalemia due to acidosis for correction of intracellular redistribution?
Sodium Bicarbonate
Use only when hyperkalemia due to acidosis
50-100 mEq IV over 2-5 minutes
Onset 30 min; duration 2-6 hours
Do not infuse through same IV line as parenteral nutrition or other calcium & phosphorous solution
What are the treatment options for removal of K+ from the body in a patient with hyperkalemia?
Furosemide (Lasix) if normal renal function
20-40 mg IV
Sodium polystyrene sulfonate (Kayexalate)
15-60 grams orally or rectally
Oral route more effective and better tolerated
Onset 1 hour or more; duration variable
Exchanges Na+ for K+
This could potentially lead into another problem. Depends on sodium levels of the patient.
Hemodialysis
What are the cardiac abnormalities associated with hypokalemia?
EKG changes- flattened T waves, presence of U wave Bradycardia PVCs Heart Block Atrial flutter/ventricular fibrillation
What are the muscle abnormalities associated with hypokalemia?
Myalgia
Muscle weakness
Cramps
Paralysis
What are the causes of hypokalemia?
GI losses (V/D, NG suction)
Inadequate K+ intake
Alkalosis
Meds
What are the meds that can cause hypokalemia?
Cellular redistribution- these are options for treating hyperkalemia so remember they can then cause hypokalemia.
B2-agonists
Insulin
Renal wasting
Loop and thiazide diuretics (not sparing but dumping it out)
High dose antibiotics ie PCN
Depletion of magnesium diminishes intracellular K+ -> K+ wasting
AmphoB, foscarnet
When should you treat hypokalemia?
- Any low serum K+ if patient symptomatic
- Underlying cardiac conditions that predisposes them to arrhythmias (cardiac therapies arent used unless there are cardiac sx)
- Receiving digoxin therapy
- Consider for patients receiving diuretics
- Laxative abuse
- Any patient with serum K+ < 3.0 mEq/L
What are the dietary sources that can be used for non-pharmacologic therapy?
Fresh fruits
Vegetables
Meats
A condition that causes a loss of potassium might also cause a loss of?
Chloride
Caused by: Diuretic therapy, vomiting, diarrhea
What are the non-pharmacologic therapy options for hypokalemia?
- some salt substitutes
- Dietary sources- fresh fruits, vegetables, and meats
- Dietary potassium is usually in form of potassium phosphate versus potassium chloride
- Most conditions cause loss of potassium and chloride so both need replacing
What is involved with pharmacologic therapy for hypokalemia?
- Pharmacological replacement therapies should accompany dietary potassium
- Administration orally in divided doses over several days until replete
- Fatalities have occurred from IV potassium replacement
- Caution with dosing in patients with renal insufficiency
Oral potassium
- Oral potassium is available as chloride, phosphate, and bicarbonate salts
- -KCl most commonly used
- -KPO4 used if depleted in both K+ and PO4-
- -KHCO3 if patient acidotic (otherwise not usually used)
- Available as elixir, effervescent tablet, microencapsulated particles, wax-matrix extended release
- -Microencapsulated particles preferred because better taste and GI tolerability
What are the oral doses involved with hypokalemia treatment?
- Prevent hypokalemia with 20 mEq/day (Good prophylaxis dose. Used if starting a patient on something like digoxin.)
- Treat mild hypokalemia with 40-100 mEq total dose
- Treat severe deficiency with 120 mEq total dose
When should IV treament be used for treatment of hypokalemia?
If oral route not feasible or life-threatening symptoms