Fluid And Electrolytes

Question 0

Clinical manifestations of slow hypernatremia versus rapid hypernatremia?

Management?

Answer 0

Volume depletion versus confusion, lethargy, coma

D5 1/2NS

versus

D5 1/3NS or even D5W

Question 1

Estimated water loss based on hypernatremia?

Answer 1

Every 3 mEq/L of hypernatremia represents 1 L of water lost

Question 2

Rule of thumb for treating hypernatremia?

Answer 2

Rapidly correct the hypovolemia, but slowly correct the tonicity

Question 3

Major causes of hyponatremia? Management?

Answer 3

1. Inappropriate ADH secretion (post-Op water intoxication, tumors)
2. Loss of large amounts of isotonic fluids (from G.I. tract)

#If rapid, hypertonic saline.
#If slow, water restriction
#If from G.I. fluid loss – isotonic fluid

Question 4

Why does G.I. fluid loss cause hyponatremia?

Answer 4

1. Loss of isotonic fluid

2. Retention of water to maintain correct volume

Question 5

Hypokalemia – typical causes? Management?

Answer 5

1. G.I. tract losses
2. Urine losses (direct, aldosterone)

10 mEq per hour

Question 6

Hyperkalemia – typical causes?

Management options - ultimate? Fastest? Others?

Answer 6

1. Kidney cannot excrete potassium (renal failure, aldosterone antagonist)
2. Dumping of potassium into blood (acidosis, crush injuries, necrosis)

#Ultimate therapy – hemodialysis
#Fastest - Ca 
#Push potassium into cells – dextrose and insulin, B-2 agonists, Bicarb 
#Suck/neutralize potassium out of G.I. tract – (NG suction, Kayexalate)

Question 7

Metabolic acidosis – general causes?

Answer 7

#Production of fixed acids (DKA, low flow states)
#Loss of buffers (blocks of bicarb)
#Inability to eliminate acids (renal failure)

Question 8

Metabolic acidosis – in addition to fixing base deficit, be prepared to replace?

Answer 8

Potassium

Question 9

Metabolic alkalosis – most cases will correct with administration of? Rarely need?

Answer 9

KCl – 5-10 mEq per hour

Ammonium chloride or .1 N HCL