Fluids and Electrolytes

Question 1

What percentage of body weight does each fluid account for: intracellular, interstitial, and intravascular?

Answer 1

Intracellular: 40%
Interstitial: 16%
Intravascular: 4%

Question 2

What is the normal serum concentration of Na, K, Ca, and Mg in mEq/L?

Answer 2

Na = 135 - 145
K = 3.5 - 4.5
Ca = 4.0 - 5.5
Mg = 1.5 - 2.5

Question 3

What is the normal serum concentration of Cl, CO2, and PO4 in mEq/L?

Answer 3

Cl = 95 - 105
CO2 = 24 - 30
PO4 = 2.5 - 4.5

Question 4

What is the daily requirement of Na, K, Ca, Mg, and PO4?

Answer 4

Na = 1 - 2 mEq/kg/day
K = 0.5 - 1 mEq/kg/day
Ca = 800 - 1200 mg/day
Mg = 300 - 400 mg/day
PO4 = 800 - 1200 mg/day

Question 5

How much Na, Cl, K, Ca, HCO3, and Glc is in plasma?

Answer 5

Na = 141
Cl = 103
K = 4-5
Ca = 5
HCO3 = 26
Glc = 0

Question 6

How much Na, Cl, K, Ca, HCO3, and Glc is in NS?

Answer 6

Na = 154
Cl = 154
K = 0 
Ca = 0
HCO3 = 0
Glc = 0

Question 7

How much Na, Cl, K, Ca, HCO3, and Glc is in D5W?

Answer 7

Na = 0
Cl = 0
K = 0
Ca = 0
HCO3 = 0
Glc = 50g

Question 8

How much Na, Cl, K, Ca, HCO3, and Glc is in LR?

Answer 8

Na = 130
Cl = 109
K = 4 
Ca = 3
HCO3 = 28
Glc = 0

Question 9

Why are most drugs made with NS or D5W?

Answer 9

Their concentrations can be adjusted while LR cannot.

Question 10

Describe the functions of aldosterone and ADH in urinary control.

Answer 10

Aldosterone: exchanges Na for K in distal tubule in response to volume reduction
ADH: increases tubular water reabsorption - released from posterior pituitary

Question 11

What fluid is best to replace losses from: sweat, gastric, biliary/pancreatic, SI, LI, 3rd space?

Answer 11

sweat: D5-1/4NS + 5mEq KCl/L
gastric: D5-1/2NS + 20mEq KCl/L
LR for the rest

Question 12

What should be done to a plasma protein binding drug dose if albumin is low?

Answer 12

Lower the dose

Question 13

Where is albumin made and what is the effect when this organ fails?

Answer 13

Liver –> liver failure decreases albumin and causes edema (ascites specifically)

Question 14

What results from serum acidosis (pH < 7.2)

Answer 14

dec response to catecholamines, dec cardiac function, arrhythmias, inc serum K.

Question 15

What are symptoms of hypoNa and what is greatest risk?

Answer 15

S/S: cramping, twitches, fasciculations. HypoNa patients are at inc risk for seizures.

Question 16

What is the first, then second indicator of decreased renal function and when is dialysis indicated?

Answer 16

1: increased creatinine
2: hyperkalemia –> dialysis needed

Question 17

What ECG changes are present in hyperK?

Answer 17

peaked Ts, long PR, lethal arrhythmias

Question 18

What are potential causes of hyperK?

Answer 18

Acidemia, hypoaldosteronism, some drugs, excess intake, WBC > 100,000, platelets > 600,000, bad blood draw, cell death (rhabdo, chemo, burns)

Question 19

What is the treatment for hyperK from least severe to most severe?

Answer 19

Sodium Polystyrene Sulfonate (Kayexalate)
D50 and Insulin (Glc takes K into cells when it enters)
Sodium Bicarbonate
Calcium Chloride

Question 20

Describe the relationship between K and pH.

Answer 20

Inverse relationship –> if K goes up pH decreases and vice versa.

Question 21

What is the fastest rate of K administration when treating hypoK?

Answer 21

10 mEq/hour IV