Body Water Districution And Composition

Question 1

How much of our bodies is made of water?

Answer 1

45-60% body weight in healthy adult

Question 2

What is body composition proportional to?

Answer 2

Proportional to (lean) skeletal muscle fraction
*lower in obese people

Question 3

How does water content vary based on age?

Answer 3

Higher proportion in younger
1. Children 60-80%
2. Normal adults 50-60%
3. Elderly adult 45-58%

Question 4

How does water content vary based on gender

Answer 4

Higher in males

Question 5

What is the total amount of body water (intracellular, Extracellular)

Answer 5

Total body water
*42,000mL (60%)
intracelllar (40%)
*28,000mL
Extracellular (20%)
*14,000mL
*plasma = 3500mL
*interstitial = 10,500mL

Question 6

What is the total blood volume (70kg man)

Answer 6

5,600mL
*8% of BW in a 70kg man

Question 7

What is the formula to get TBW?

Answer 7

Weight (kg) X 0.6L = TBW

EX: 70kg man
70 X 0.6 = 42L

Question 8

What is the main intracellular cation

Answer 8

K+
*balance by phosphate and negatively charged protein

Question 9

What is the main Extracellular cation

Answer 9

Na+
*balanced mainly by chloride ion (Cl-)

Question 10

What is the normal fluid intake

Answer 10

Oral liquids = 1500ml
Oral solids = 700ml
Metabolic (endogenous) = 300ml
Total = 2500

Question 11

What is the normal fluid output

Answer 11

Urine = 800-1500ml
Stool = 250ml
Insensible losses = 600-900
Total = 1400-2300

Question 12

What are factors that affect renal control of sodium and water excretion

Answer 12

1. Aldosterone
2. Renin-angiotensin cascade
3. Aderenocorticotropci hormone (ACTH)
4. Anti diuretic hormone (ADH)

Question 13

What does aldosterone do

Answer 13

Controls sodium reabsorption in exchange for K+ and hydrogen ion secretion in distal tubules

Question 14

What is the baseline fluid requirement of a 70kg adult

Answer 14

35mL

Question 15

How to calculate baseline fluid replacement if the patient is not 70kg

Answer 15

1. 100mL for the first 10kg
2. 50ml for the second 10kg
3. 20ml for weight above 20kg

Question 16

What is the baseline fluid requirement for urine, stool, sweat, skin and lungs

Answer 16

Urine = 12-15
Stool = 3
Sweat = 0-1.5
Skin and lungs =10

Question 17

What are the lyte requirements for sodium, chloride (70kg)

Answer 17

1. Sodium
   *80-120mEq
2. Chloride
   *80-120

Question 18

What is the normal intake for potassium

Answer 18

50-100mEq/d
*98% of potassium is intracellular
*potassium demands increase with diuresis and building of new body tissues

Question 19

What supplements do not have routine administration

Answer 19

Calcium
*only needed is symptomatic
Magnesium
*indicated alcohol abuse
*Massive diuresis
*pre-eclampsia

Question 20

What is the glucose requirement needed

Answer 20

100-200g/day will reduce protein loss by 50%
1. During starvation caloric needs supplied by body fat and protein
2. Protein-shaping effect is one of the goals of basic IV therapy