Fluids & Electrolytes

Question 1

Major cation intracellular and extracellular

Answer 1

outside: Na+
inside: K+

Question 2

Main anions in body fluids

Answer 2

PO4, Cl, bicarb

Question 3

What makes up total body water volume?

Answer 3

ICF

ECF: interstitial (80%) + plasma (20%)

Question 4

Water makes up what percent of body?

Answer 4

60%

Question 5

What is colloid typically composed of?

Answer 5

5% albumin in water

Question 6

Replace blood with ________.

Answer 6

blood

Question 7

Resuscitate with what fluid replacement?

Answer 7

isotonic fluid or colloid

Question 8

Replace ECF depletion with ________.

Answer 8

isontonic (NS or LR)

Question 9

Rehydrate with _________.

Answer 9

hypotonic (D5W)

Question 10

Net effect of IV normal saline

Answer 10

increase water and volume in the vascular and intersititial spaces, but NOT the intracellular space

Question 11

Net effect of IV whole blood

Answer 11

ONLY increase intravascular volume space; RBCs can’t across compartments

Question 12

Net effect of IV colloid (5% albumin)

Answer 12

increase water and volume in the vascular and intersititial spaces, but NOT the intracellular space

• same as NS, but stays in intravascular space a little longer

Question 13

Net effect of IV Dextrose 5%

Answer 13

small increase in ICF and ECF fluid

behaves like pure water flowing freely across all compartments

Question 14

Examples of hyperosmotic fluids that pull water from interstitial AND intercellular spaces to balance osmolality

Answer 14

Mannitol, D50, 25% albumin

Question 15

Do not use ______ for resuscitation.

Answer 15

hypotonic fluids

Question 16

Which type of fluids pull fluids from ICF to ECF to balance tonicity?

Answer 16

hypertonic fluids (3% saline)

Question 17

4cc, 2cc, 1cc rule for fluids

Answer 17

4 cc for the first 10 kg
2 cc for the next 10 kg
1 cc for each kg after

Question 18

What is cc/hr rate of fluids for a 70 kg adult who is euvolemic?

Answer 18

4 cc for the first 10 kg = 40cc
2 cc for the next 10 kg = 20cc
1 cc for each kg after = 50cc
110 cc/hr

Question 19

How to calculate daily maintenance fluid requirements?

Answer 19

0-10 kg: 100 ml/kg
10-20 kg: 1000 ml + 50 ml/kg for each kg over 10
20 kg: 1500 ml + 20 ml/kg for each kg over 20

Question 20

What are daily maintenance requirements of sodium, chloride, and potassium?

Answer 20

Na+ 3 meq/kg
Cl- 5 meq/kg
K+ 2 meq/kg

Question 21

A 70 kg male is 2 days post-colectomy. He is euvolemic, and he is NPO. His electrolytes are normal. His urine output is 63 ml/hour. He has a post-op drain with 100 ml serous output every 6-hours.

How much fluid does he need in the next 24 hours?

Answer 21

Insensible losses = 500 ml
63 ml/hr x 24 hours = 1500 ml
100 ml x 4 (four 6-hours in 24-hours) = 400 ml

His losses will be 2400 ml in 24 hours, so he needs 2400 ml, or 100 ml/hr

Question 22

A 70 kg male is 2 days post-colectomy needs 2400 ml/day because his is NPO. His electrolytes are normal.

What do his losses look like?

Answer 22

Insensible - water
Urine – water and some electrolytes (~1/2NS)
Drain - serum

Question 23

Which IV fluids have potassium?

Answer 23

LR and D51/2NS-20 K+

Question 24

Which IV fluids have glucose?

Answer 24

D5W, D5NS, D51/2NS

Question 25

cc in can of soda?

Answer 25

375 cc

Question 26

Which fluid type and how much is bolus dosing amount?

Answer 26

use isotonic fluids
bolus is 10-20 ml/kg in hypovolemia
10 kg child = 100-200 ml, 100 kg adult = 1-2 L

Question 27

Why do bolus dosing?

Answer 27

rapidly increase intravascular volume when there is evidence of dehydration and hypoperfusion

Question 28

How to treat hypokalemia?

Answer 28

Non-life threatening (K less than 2.5) or asymptomatic: oral KCl 20-40 mmol q4-6 hrs x 4 doses, redraw next morning

Life-threatening: IV KCl 40 mmol over 2 hrs via central catheter, redraw every 30 min

Question 29

How to treat hyperkalemia?

Answer 29

“C-Big-Kay-Di”

C – Calcium gluconate (stabilizes cardiac membrane)
B – Beta-2 agonists like nebulized albuterol or Bicarbonate (both shift K into cells)
IG – Insulin + Glucose (insulin shifts K into cells + glucose to avoid hypoglycemia)
K – Kayexalate (binds K in gut, excreted in feces lowering total body K stores)
DI – DIuretics (lasix) or DIalysis (if refractory to all other treatment options)

Question 30

Etiology of hyponatremia with hypovolemia and low FE Na and sodium urine output?

Answer 30

vomiting, diarrhea, fluid loss (third spacing)

Question 31

Etiology of hyponatremia with hypovolemia and high FE Na (> 1%) and sodium urine output?

Answer 31

Diuretics
Aldosterone deficiency
Renal tubular dysfunction

Question 32

Etiology of hyponatremia with hypervolemia and low FE Na?

Answer 32

CHF
Cirrhosis
Renal failure

Question 33

When to use hypertonic saline?

Answer 33

severe life-threatening symptoms of euvolemic hyponatremia - seizures, coma, impending respiratory distress

Question 34

Etiology of euvolemic hyponatremia?

Answer 34

Polydipsia if low urine osmolality

SIADH if high urine osmolality

Question 35

How to treat hyponatremia?

Answer 35

Hypovolemic - NS
Hypervolemic - treat underlying cause (eg. CHF)
Euvolemic - restrict water intake, NS or hypertonic saline

Question 36

Why must sodium levels be corrected slowly?

Answer 36

avoid central pontine myelinolysis (cerebral edema)

Question 37

Treatment of hypernatremia

Answer 37

NS if hemodynamically unstable

Hypotonic fluid if stable - drink water, IV fluids

Question 38

Rate of correction for acute vs chronic hypernatremia

Answer 38

Acute 1 mmol/L/h

Chronic 0.5 mmol/L/h

Question 39

How to manage hyperglycemic syndromes?

Answer 39

Fluids: crystalloids, add glucose when 250-300 mg/dL
Regular insulin
Electrolytes: K if less than 3.3 mmol/L

Question 40

What glucose range is the goal for hyperglycemic patient who is critically illness?

Answer 40

140-180 mg/dL

Question 41

Give _____ for hyperkalemia with ECG changes.

Answer 41

calcium

Question 42

Limit increase in serum Na to _______ in first 24 hours in symptomatic hyponatremia.

Answer 42

8-12 mmol/L

Question 43

Patients with hypernatremia and hemodynamic instability should have __________ administered.

Answer 43

normal saline

Question 44

Potassium should be added to fluids in hyperglycemic syndromes as soon as K ________ and urine output is adequate.

Answer 44

K less than 5 mmol/L

Question 45

Why should D5W (hypotonic) not be given to infants or patients with a head injury?

Answer 45

may cause cerebral edema