Fluid Balance

Question 1

What is the body’s fluid balance dependent on?

Answer 1

Homeostasis is dependent on fluid, electrolyte, & acid-base balance

Question 2

What can disrupt fluid balance?

Answer 2

1. Surgery
2. Illness
3. Injury

Question 3

How is fluid gained?

Answer 3

1. GI tract
   A. Food
   B. Liquids

Question 4

How is fluid lost?

Answer 4

1. Skin
2. Lungs
3. Intestines
4. Urinary tract

Question 5

What are the body fluid compartments?

Answer 5

Total body fluid (TBF) = extracellular fluid (ECF) + intracellular fluid (ICF)

Question 6

Define ICF

Answer 6

Fluid w/in individual cells of body

Question 7

Define ECF

Answer 7

All body fluids NOT contained in cells

Question 8

What are the subcategories of ECF?

Answer 8

Includes intravascular & interstitial fluid

Question 9

Define intravascular fluid

Answer 9

Fluid w/in plasma & lymph system

Question 10

Define interstitial fluid

Answer 10

Fluid in tissues that fills spaces between cells

Question 11

Define hypovolemia

Answer 11

1. Low blood volume
   A. Body loses both water & electrolytes from ECF
   B. ↓ Plasma / ↓ Na

Question 12

Define dehydration

Answer 12

1. Water loss w/out accompanying electrolyte loss

A. ↑ K /↑ Na

Question 13

What can cause hypovolemia?

Answer 13

1. Abnormal GI loss
A. V/D/NG 
2. Abnormal renal loss
A. Diuresis/DI, Addison’s Dz
3. Plasma loss (3rd spacing)
A. Peritonitis, intestinal obstruction, ascites, burns, vasodilation w/edema
4. Blood loss
A. Int. or ext. hemorrhage

Question 14

What can cause dehydration?

Answer 14

1. Hyperventilation
2. DKA
3. Insufficient water intake
4. Abnormal skin loss
   A. Diaphoresis

Question 15

How does the body compensate for fluid loss?

Answer 15

1. Sympathetic Nervous System
   A. Increased thirst
   B. ADH release
   C. Aldosterone release

Question 16

What are the sxs of hypovolemia?

Answer 16

1. Dizziness/faint
2. Confusion
3. Weakness
4. Fatigue
5. Nausea
6. Thirst
7. Tachycardia
8. Tachypnea
9. Hypotension
10. Oliguria
11. Orthostasis
12. Poor cap refill
13. Pallor

Question 17

What are the sxs of dehydration?

Answer 17

1. Thirst
2. Headache
3. ↓ Appetite
4. Dry skin
5. Confusion
6. Fatigue
7. Irritability
8. Constipation
9. Hypotension
10. Orthostasis
11. Tachypnea
12. Tachycardia
13. Oliguria

Question 18

What are the diagnostic studies for fluid loss?

Answer 18

1. Hgb & Hct
A. Dehydration: up
B. Hypo: down
2. Serum osmolality
A. Dehydration: up
B. hypoV: down
3. Serum albumin
A. Dehydration: up
B. hypoV: equal or down
4. Urine SG
A. Dehydration: up
B. HypoV: equal or down
5. Serum Na
A. Dehydration: up
B. HypoV: Down
6. Central venous pressure (CVP)
A. Dehydration: down
B. hypoV: down by a lot
7. Pulmonary wedge pressures (PWP)
A. Dehydration:
B. HypoV:

Question 19

What does CVP measure?

Answer 19

1. Direct measurement of BP in the right atrium & vena cava
   A. Normal CVP is 2-6 mm Hg
2. Assesses right ventricular function & systemic fluid status

Question 20

Where does the CVP catheter measure the pressure?

Answer 20

Tip of central venous multi-lumen catheter rests in the lower 1/3 of SVC

Question 21

What is the pulmonary wedge pressure?

Answer 21

1. Pressure measured by wedging a pulmonary catheter w/ inflated balloon into a small pulmonary arterial branch
2. Provides indirect measurement ofleft atrialpressure
   A. Normal 2-15 mmHg

Question 22

What are the other names for pulmonary wedge pressure?

Answer 22

1. Pulmonary arterial wedge pressure (PAWP)
2. Pulmonary capillary wedge pressure (PCWP)
3. Pulmonary venous wedge pressure (PVWP)
4. Pulmonary artery occlusion pressure (PAOP)

Question 23

What is PWP used for?

Answer 23

Used to diagnose severity of LVF & mitral stenosis

Question 24

What is the gold standard for diagnosing acute pulmonary edema?

Answer 24

1. PWP

A. PWP of >20mmHg indicates edema

Question 25

What are the implications of hypovolemia?

Answer 25

1. Decreased cardiac output 2. Ineffective tissue perfusion 3. Deficient fluid volume

Question 26

What are the complications of hypovolemia?

Answer 26

Hypovolemic Shock | Vital organ hypoxia

Question 27

What is over hydration?

Answer 27

Water replacement w/out electrolyte replacement

Question 28

What is hypervolemia?

Answer 28

1. Chronic stimulus to kidneys to conserve Na & water 2. Abnormal renal function/renal failure 3. Fluid shifts from interstitium to plasma 4. Excessive Na intake

Question 29

How does the body compensate for excess body fluid?

Answer 29

1. Increase release of natriuretic peptides A. ↑ Na & water loss by kidneys B. ↓ aldosterone release

Question 30

What are the sxs of hypervolemia?

Answer 30

1. Confusion 2. SOB 3. Orthopnea 4. Tachycardia 5. HTN 6. Edema 7. Weight gain 8. Crackles/rales 9. JVD

Question 31

What are the dx studies for overhydration?

Answer 31

1. Overhydration A. ↓ Hb & Hct B. ↓ Serum osmolality C. ↓ Serum Na

Question 32

What are the dx studies for hypervolemia (renal)?

Answer 32

1. ↑ Lytes 2. ↑ BUN Creatinine w/ CKD 3. BNP A. less than 100 pg/mL suggests cardiac cause is unlikely

Question 33

What are the implications of hypervolemia?

Answer 33

1. Impaired gas exchange A. Hypoxia 2. Excess fluid volume 3. Impaired skin integrity

Question 34

How is hypervolemia treated?

Answer 34

1. Monitor ABG’s for hypoxemia & respiratory alkalosis 2. Continuous PaO2 3. Telemetry 4. Administer oxygen as needed 5. Administer loop diuretics 6. Monitor daily I & O 7. Limit fluids & Na

Question 35

What are the complications for hypervolemia?

Answer 35

1. Pulmonary Edema | A. Ascending crackles, dyspnea at rest, confusion

Question 36

How is Pulmonary edema treated?

Answer 36

1. IV Morphine 2. IV Diuretic 3. Prepare for possible intubation & mechanical ventilation