Fluids

Question 1

Extracellular fluid compartment

Answer 1

1. Intravascular = fluid component of blood
2. Interstitial = fluid surrounding cells 3rd spacing
3. Transcellular = CSF, pericardium, synovial fluid

Question 2

Principal Extracellular Fluid Electrolytes

Answer 2

Sodium
Bicarbonate
Chloride

Question 3

Principal Intracellular Fluid Electrolytes

Answer 3

Potassium
Magnesium
Calcium

Question 4

Intracellular Fluid (ICF) Calculations

Answer 4

2/3 of TBW

Question 5

Extracellular Fluid (ECF) Calculations

Answer 5

1/3 of TBW*

a. Interstitial = 3/4 x total ECF
b. Intravascular = 1/4 x total ECF

Question 6

Two factors that regulate total body volume

Answer 6

1. Osmolality

2. Total Body Water

Question 7

Baroreceptors sense change in what compartment of the body for fluid volume regulation?

Answer 7

Intravascular

Question 8

T/F: Osmolality always overrides effective blood volume

Answer 8

False; Other way! (Think about Edema)

Question 9

Osmolality Critical Values:

Answer 9

<260 =

>330 =

Question 10

Must look at both serum [Osm] and ___________ in the patient to assess fluid balance.

Answer 10

total fluid volume

Question 11

What can cause a low serum [Osm] but does not indicate excess water in the patient?

Answer 11

Loss of electrolytes, especially Na+

Question 12

Hydrostatic pressure pushes fluids ___________ of cell and the interstitial space and ______________ of circulation. Oncotic pressure pushed fluid _________ of cells and the interstitial space and _________ of circulation.

Answer 12

Inside; Out

Ouside; Into

Question 13

Hypovolemia

Answer 13

Loss of body fluid in the intrastitial and/or intravascular space

Question 14

Two types of hypovolemia:

Answer 14

1. Total body water loss

2. Intravascular hypovolemia - fluid not appropriately distributed

Question 15

Symptoms of Dehydration

Answer 15

1. Rapid weightloss (fluid v fat)
2. Decreased skin turgor
3. Oliguria (decreased output)
4. Concentration urine
5. Weak, RAPID pulse
6. Decreased BP (<90/<60), orthostasis (Diastolic drop 10 mmHg; Systolic drops 20 mmHg)
7. Prolonged capillary filling time - Finger nail bed test
8. Sensation of thirst, weakness, dizziness, muscle cramps

Question 16

Lab Findings for dehydration

Answer 16

1. High [Osm] due to lots of fluid loss
2. Low [Osm] due to lots of SODIUM loss
3. Blood: High HCT, BUN:Cr ratio > 20:1
4. Urine: High osmolality {>300 mOsm/kg)

Question 17

How do you establish severity of dehydration?

Answer 17

Look at weight loss
Mild: 2%
Moderate: 6%
Severe: 10%

Question 18

How do you implement fluid replacement in patients?

Answer 18

Must include: Maintenance + Deficit + Ongoing loss

1. Replace 1/2 of deficit in the first 24 hours
2. Replace remaining deficit in the next 48 hours
3. Replace ongoing fluid loss mL/mL

Question 19

What types of fluids can we use for fluid replacement and where do they go?

Answer 19

1. D5W = Intravascular space; Behaves like water (Even distribution)
2. 1/2 NS = Hypotonic solution acting as 1/2 free water and 1/2 NS in the body
3. NS = Expands to ECF
4. 3% sodium chloride

Question 20

Need to increase blood pressure, which fluid replacement option would you use?

a. D5W
b. 1/2 NS
c. NS
d. 3% sodium chloride

Answer 20

Normal Saline due to increased fluid to interstitial space

Question 21

Low blood volume and normal sodium content fluid replacement:

a. D5W
b. 1/2 NS
c. NS
d. 3% sodium chloride

Answer 21

a. D5W

Question 22

Hypervolemia

Answer 22

Thirdspacing of fluid resulting in Edema and Ascities

Question 23

Symptoms of hypervolemia

Answer 23

1. Decreased output
2. Increased HR
3. Decreased BP
4. Rapid Weight increase
5. Pitting edema: Location, bilateral? and how high
6. hematoma

Question 24

Bilateral versus Unilateral edema

Answer 24

Bilateral = ORGAN FAILURE
Unilateral = some other disease pathway

Question 25

How do we manage hypervolemia?

Answer 25

1. Treat underlying disease 2. Restrict fluid replacement 3. Administer diuretics/colloids

Question 26

Best recipient of colloid infusion?

Answer 26

Patient with low albumin levels to increase colloid pressure

Question 27

Patient is dehydrated, which fluid replacement should you use to expand volume? a. D5W b. 1/2 NS c. 25% colloid infusion d. 3% sodium chloride e. 5% colloid infusion f. NS

Answer 27

e. 5% colloid infusion = iso-oncotic

Question 28

Patient has edema and low albumin levels, which fluid replacement option should you use? a. D5W b. 1/2 NS c. 25% colloid infusion d. 3% sodium chloride e. 5% colloid infusion f. NS

Answer 28

c. 25% colloid infusion

Question 29

What defines oliguria?

Answer 29

< 400 mL of urine output in 24 H (for adults)

Question 30

What defines orthostasis?

Answer 30

>20 mmHg change in systolic BP with sitting & standing BP >10 mmHg change in diastolic BP with sitting & standing BP

Question 31

Serum Osm when water loss >> Na loss

Answer 31

Hyperosmolarity > 330 mmol/L (hypovolemia)

Question 32

Serum Osm when water loss << Na loss

Answer 32

Hyposmolarity < 260 mmol/L (hypovolemia)

Question 33

What lab values increase with hypovolemia?

Answer 33

``` HCT Proteins Electrolytes (sometimes!! Complex...) BUN: Creatinine > 20:1 Urine osmolality (>300 mOsm/kg, concentrated urine) ```

Question 34

Mild dehydration (weight loss only, know that symptoms can add urgency)

Answer 34

2% weight loss (acute)

Question 35

Moderate dehydration (know that symptoms add urgency)

Answer 35

6% weight loss (acute)

Question 36

Severe dehydration (know that symptoms add urgency)

Answer 36

10% weight loss (acute)

Question 37

0-10 kg patient fluid needs

Answer 37

100 mL/kg

Question 38

10-20 kg patient fluid needs

Answer 38

1000 mL + 50 mL/kg over 10

Question 39

>20 kg patient fluid needs

Answer 39

1500 mL + 20 mL/kg over 20

Question 40

Adults fluid needs "rule of thumb"

Answer 40

30-35 mL/kg/day

Question 41

Fluid replacement strategy and time line:

Answer 41

Day 1: replace 1/2 of the deficit lost in first 24 hours (PLUS MAINTENANCE NEEDS, 1 kg lost = 1 L water) Day 2/3: replace remaining deficit in the next 48 hours (plus maintenance needs) Replace ongoing fluid loss mL/mL

Question 42

Cautions in replacing fluid loss with hypovolemic patients:

Answer 42

``` Renal failure Hepatic failure Cardiac failure Elderly (Pre-disposed to fluid overload, start low and go slow) ```

Question 43

``` D5W: Tonicity Dextrose content ECF% ICF% Free water/L ```

Answer 43

``` Hypotonic (no NaCL) Dextrose 5 g/dL 40% ECF 60% ICF 1 L free water ```

Question 44

``` 0.45% NaCL: Tonicity NaCl mEq/L ECF% ICF% Free water/L ```

Answer 44

``` Hypotonic 77 mEq/L Na; 77 mEq/L Cl 66.5% ECF 33.5% ICF 0.5 L free water ```

Question 45

``` 0.9% NaCl: Tonicity NaCl mEq/L ECF% ICF% Free water/L ```

Answer 45

``` Isotonic 154 mEq/L Na; 154 mEq/L Cl 100% ECF 0% ICF 0 L free water ```

Question 46

``` 3% NaCl: Tonicity NaCl mEq/L %ECF %ICF Free water/L ```

Answer 46

``` Hypertonic 513 mEq/L Na; 513 mEq/L Cl 100% ECF 0% ICF -2.33 L free water ```

Question 47

``` Hypervolemia sign/symptoms: Urine output HR BP Weight ```

Answer 47

``` Decreased urine output Increased HR Decreased BP Increased weight (Edema/ascites/hematoma) ```

Question 48

Pitting edema scale 1+

Answer 48

2 mm (lowest scale)

Question 49

Pitting edema scale 2+

Answer 49

4 mm (2nd)

Question 50

Pitting edema scale 3+

Answer 50

6 mm (3rd)

Question 51

Pitting edema scale 4+

Answer 51

8 mm (4th)

Question 52

Management of hypervolemia (3):

Answer 52

1. Treat underlying disease 2. Restrict fluids 3. Diuretics (loop are most effective, thiazides, K+ sparing if underlying disease would make it rational) 4. Colloids given if proteins v. Low

Question 53

Therapeutic fluids (2) with hypervolemia:

Answer 53

Colloid solutions | Oxygen-carrying resuscitation solutions (Blood, PRBC)

Question 54

Albumin 5% indication | Oncotic comparison with plasma

Answer 54

``` Hypovolemic patients (low BP) Iso-oncotic with plasma ```

Question 55

25% albumin solution indication

Answer 55

Given when fluid intake needs are minimized or oncotic pressure needs are raised (edema)

Question 56

Drug-induced cause from amphotericin B, aminoglycosides (kidney tubule damage), and long-term diuretic therapy

Answer 56

Hypomagnesemia (also caused from GI/renal loss and poor intake/absorption)

Question 57

Signs/symptoms of hypomagnesemia usually not seen until

Answer 57

< 1 mg/dL

Question 58

S/S: CNS & CV lethargy, weakness, fatigue, confusion V-tach, V-fib, premature ventricular contractions

Answer 58

Hypomagnesemia (usually not seen until < 1 mg/dL)

Question 59

1 g = ___ mEq Mg

Answer 59

8.1 mEq

Question 60

Treatment of hypomagnesemia WITH symptoms AND < 1 mg/dL Mg:

Answer 60

1. IV magnesium sulfate: 2 g bolus | 2. Continuous infusion to replenish body stores: 0.5-1 mEq/kg/24 H over 2-5 days

Question 61

Treatment of hypomagnesemia WITHOUT symptoms AND < 1 mg/dL Mg:

Answer 61

1. Continuous infusion ONLY: 0.5-1 mEq/kg/24 H over 2-5 days (to replenish body stores)

Question 62

Treatment of hypomagnesemia without symptoms and Mg > 1 mg/dL:

Answer 62

1. Magnesium oxide supplement: 400-800 mg QID (242 mg of elemental Mg)

Question 63

Seen in renal failure patients taking antacids or laxatives or with excessive doses in hospitalized patients

Answer 63

Hypermagnesemia

Question 64

Decreased tendon reflexes Muscle weakness Sedation Vasodilation

Answer 64

S/S of hypermagnesemia

Question 65

Treatment of hypermagnesemia (3):

Answer 65

1. DC magnesium source 2. Ca++ to reverse effects 3. Administer diuretics to promote excretion