Fluids and Electrolytes

Question 1

normal serum osmolality

Answer 1

285-295

Question 2

meds that can cause SIADH

Answer 2

LOOK AT SLIDE

Question 3

goal rate of correction for hyponatremia that is asymptomatic

Answer 3

increase of Na+ by less than or equal to 0.5 mEq/hour

less than 10-12 mEq/day

Question 4

goal rate of correction for hyponatremia that is symptomatic (seizures, altered mental status)

Answer 4

increase in Na+ by 1-2 mEq/h for first few hours

no more than 12 mEq/day

Question 5

hypotonic hypovolemic treatment

Answer 5

Correct underlying cause if possible
IV 0.9% NS
(if severe sx, then consider 3% saline but be careful with rate of correction –> hourly serum Na monitoring)

Question 6

hypotonic euvolemic treatment

Answer 6

• Correct underlying cause if possible (D/C meds)
• Fluid restriction (less than 1000 mL/day)
• Severe sx= consider IV 3% NS +/- loop diuretic (avoid in HF pts)
• Demeclocycline= long term
• Urea= C/I in pts with renal or hepatic failure
• AVP receptor antagonists (“-vaptans”)= C/I in hypovolemic pts

Question 7

brand name for conivaptan

Answer 7

Vaprisol

Question 8

brand name for tolvaptan

Answer 8

Samsca

Question 9

treatment for hypotonic hypervolemic hyponatremia

Answer 9

• treat underlying condition
• HF= ACEI/ARB, digoxin
• Diuretics in HF, cirrhosis
• fluid restriction (less than 1000 mL/day
• AVP receptor antagonists

Question 10

goal rate of correction for chronic (or unknown length of time) hypernatremia

Answer 10

decrease Na+ by less than or equal to 0.5 mEq/h

less than 10-12 mEq/day

Question 11

goal rate of correction for acute (developed over several hours) hypernatremia

Answer 11

decrease Na+ by 1-2 mEq/h for first few hours (no more than 10-12 mEq/day)

Question 12

treatment for hypovolemic hypernatremia

Answer 12

0.9% NS 200-300 mL/h continuous infusion until hemodynaically stable –> 0.45% NS or D5W (to correct water deficit)

Question 13

treatment for euvolemic hypernatremia- Central Diabetes Insipidus

Answer 13

Desmopressin (ADH replacement)

other agents= chlorpropamide, carbamazepine, clofibrate

Question 14

treatment for euvolemic hypernatremia- Nephrogenic Diabetes Insipidus

Answer 14

need to correct underlying disorder (does not respond to ADH treatment)
may utilize thiazide diuretics and salt restriction

Question 15

treatment for hypervolemic hypernatremia

Answer 15

• loop diuretics (furosemide 20-40 mg)

- consider D5W based on water deficit

Question 16

hypokalemia assessment

Answer 16

determined by urine K+

• less than 20= extrarenal (diarrhea, laxatives)
• > 20= renal losses (drugs, renal tubular acidosis, vomiting)

Question 17

most common causes of hypokalemia

Answer 17

1. ) drug-induced
2. ) diarrhea
3. ) vomiting

Question 18

For every 1 mEq/L drop in K+ below 3.6 is a total body deficit of ___

Answer 18

100-400 mEq/L

Question 19

which oral K+ supplement is good for diuretic and diarrhea-induced hypokalemia

Answer 19

potassium chloride

Question 20

which oral K+ supplement is good for decreased phosphorus?

Answer 20

potassium phosphate

Question 21

which oral K+ supplement is good for pts with metabolic acidosis?

Answer 21

potassium bicarbonate

Question 22

max rate of administration for peripheral vein

Answer 22

10 mEq/hour

Question 23

max rate of administration for central line

Answer 23

40 mEq/hour

Question 24

other hypokalemia treatment

Answer 24

correct Mg deficiency (PO preferred)

Question 25

hyperkalemia treatment

Answer 25

• Ca IV bolus over 2-3 min to stabilize cardiac membrane
• insulin therapy (give 10 units with 50 mL of D50 and omit dextrose if hyperglycemic)
• nebulized B2 agonists (albuterol)= gives additive effect to insulin
• sodium bicarb= increases blood pH
• ion exchange resins (sodium polysterene)= given w/sorbitol
• dialysis=most effective