3 Fluid and Electrolyte Management Rushing

Question 1

What is the body fluid composition like for a newborn?

Answer 1

Full term newborn: 75-80% total body water. 1st week of life: decrease by 4-5%. 1 year: decrease to adult levels 60%. Extracellular water content decreases with total body water content from 45% (at birth) –> 20-25% of adult levels by 1 year of age

Question 2

What component is the driving force in Plasma water?

Answer 2

Sodium

Question 3

What component is the driving force in Intracellular fluid compartment?

Answer 3

Potassium

Question 4

What is renal function like in a newborn?

Answer 4

Term newborn has GFR ~25% of an adult. Increase during 1st few weeks of life achieving adult levels ~2 years. Low concentration capacity counteracts with low GFR. Limited compensatory mechanism so become more sensitive to hypovolemia. Newborn kidney has more “holes” leading to a lower ability to concentrate urine and excrete larger molecules

Question 5

What is the concentrating ability of a newborns kidney?

Answer 5

Term infant increase urine osm to 600-700mOsm/kg. Adults increase to 1,200 mOsm/kg. Free water clearance greater in infants than adults. ADH regulate osmolality of ECF

Question 6

Which children are at a higher risk for dehydration?

Answer 6

Higher frequency of gastroenteritis (diarrhea and vomiting). Higher body surface area to volume ratio - leading to higher insensible losses. Inability to communicate and independently drink (infants/toddlers). Maturing renal compensatory pathways

Question 7

What is Dehydration?

Answer 7

Intravascular fluid depletion (loss of plasma-free water disproportionate to loss of sodium) {common when ill child rehydrated w/ too little free water}

Question 8

What is Volume Depletion?

Answer 8

Contraction of the total intravascular plasma pool {most common in pediatrics d/t increase insensible losses}

Question 9

What are the most common signs of a child being dehydrated?

Answer 9

Irritable. Dry mucous membranes. No tears. Slowed capillary refill. Decreased turgor. Rapid/weak HR. Sunken anterior fontanelle

Question 10

What is Isonatremia?

Answer 10

130-150

Question 11

What is Hyponatremia?

Answer 11

< 130

Question 12

What is Hypernatremia?

Answer 12

> 150

Question 13

What happens to potassium during a deficit?

Answer 13

It will shift from ICF to ECF with free water shifts so may actually be depleted despite level wnl - wait to ENSURE VOIDING prior to replacement

Question 14

How much fluid do you give for MAINTENANCE?

Answer 14

100ml/kg for first 10kg. 50ml/kg for next 10kg (11-20). 20ml/kg for each kg greater than 20

Question 15

Whats a quick alternative way to figure out the maintenance fluids?

Answer 15

“4-2-1”. First 10kg = 4ml/kg/hr. Second 10kg = 2ml/kg/hr. Weight > 20kg = 1ml/kg/hr

Question 16

What is done to treat mild/moderate dehydration?

Answer 16

Oral Rehydration Therapy (ORT). 10-20ml/kg to replace 1-2% loss over 6-8 hrs. Readily available (Pedialyte, Rehydralyte)

Question 17

How much sodium is in “Normal Saline”?

Answer 17

154 mEq/L (0.9%)

Question 18

What is found in Ringers Lactate?

Answer 18

Na, Cl, Ca, K, Lactate

Question 19

How much fluid is in a NS Bolus?

Answer 19

10-20ml/kg NS over 1 hr

Question 20

What is done for Acute Severe Hyponatremia?

Answer 20

Serum Na < 120, CNS symptoms. Administer 3% sodium chloride solution. 6ml/kg raises Na by ~5mEq/L

Question 21

What is the daily Na requirement?

Answer 21

1-4 mEq/kg/day

Question 22

What is the daily K requirement?

Answer 22

1-3 mEq/kg/day

Question 23

What is typically given to infants < 10kg?

Answer 23

Typically D5-0.2% NaCl + 10mEq KCl/L

Question 24

What is typically given to infants > 10kg?

Answer 24

D5-0.45% NaCl + 20mEq KCl/L

Question 25

What rate is fluid given to infants?

Answer 25

40ml/hr = ~1000 ml/day (10kg).