Pediatric Blueprints Chp 7 Fluid, Electrolyte, And Ph Management

Front 1

How does the human body weight change since when a human is born?

Back 1

Initially human is 90% water, by first year of life muscle mass increases and by 1 year of age, 60% body weight is water

Front 2

what are critical to the maintenace of normal physiology?

Back 2

Electrolyte homeostasis, fluid distribution, and pH balance. The younger the patient the more intolerant he is to challeng of these symptoms

Front 3

What are mainteance fluids?

Back 3

Amount of fluid needed to maintain normal body function. Related to caloric expenditure and child's weight

Front 4

What is the Holliday-Seger Method?

Back 4

4ml/kg/hr for the first 10kg
2ml/kg/hr for the second 10kg
1ml/kg/hr for each additional kg

Front 5

What electrolytes are necessary in maintenance fluids?

Back 5

3 mEq of sodium and 2 mEq of potassium as well as carbohydrate source

One-fourth to one-half normal saline with 5% dextrose (10% in infants) and 20mEq/L KCl meets mainteance glucose and electrolyte needs

Front 6

Why do most pediatric patients have dehydration?

Back 6

Vommiting, diarrhea, immature kidney

Front 7

What are quantitiave measures of fluid loss?

Back 7

Recent weight loss and decreased urine output

Front 8

What are some chronic medical illnesses that may present acutely with dehyration?

Back 8

diabetes, metabolic disorders, cystic fibrosis, and congenital adrenal hyperplasia

Front 9

what three coniditions may have poluria in the presence of physical signs of dehydration?

Back 9

Diabetes Mellitus
Diabetes Inspidus
Renal Tubular Acidosis

Front 10

What are the child's primary mechanism of compensationg for decreased plasma volume?

Back 10

tachycardia, hypotension
very late and ominous finding

Front 11

What are the clinical factors found in mild dehydration?

Back 11

Weight: <5% weight loss, Vitals: increased heart rate, normal RR, normal BP
Skin: <2 sec cap refil, normal/dry mucous membranes, nl Anterior fontanelle
Eyes: normal tearing, normal appearace
Mental: Normal
Lab Values: Urine 600 mOsm/L. 1.020 specific gravity, BUN<20, normal pH
NOT IN SHOCK

Front 12

What are the clinical factors found in moderate dehydration?

Back 12

Weight: 5-10% weight loss, Vitals: increased heart rate, normal RR, normal BP (orthostasis)
Skin: 2-3 sec cap refil, dry mucous membranes, depressed Anterior fontanelle
Eyes: absent tearing, sunken appearace
Mental: Altered
Lab Values: Urine 800 mOsm/L. 1.025 specific gravity, BUN elevated, mildly acidotic pH
COMPENSATED SHOCK

Front 13

What are the clinical factors found in severe dehyration?

Back 13

Weight: >10% weight loss, Vitals: greatly increased heart rate, increased RR, decreased BP
Skin: >3 sec cap refil, dry mucous membranes, depressed Anterior fontanelle
Eyes: absent tearing, sunken appearace
Mental: Depressed
Lab Values: Urine Max mOsm/L, High specific gravity, BUN elevated, mildly acidotic pH
UNCOMPENSATED SHOCK

Front 14

What helps guide the choice of fluid composition and rate of replancement?

Back 14

Serium electrolyte level: hypotonic(hyponatremic), Hypertonic (hypernatremic), isotonic

Front 15

What is the most common form of dehyration?

Back 15

Isotonic dehyration is the most common form and suggest that either compensation has occured or that water loss roughly parallels sodium losses

Front 16

What is the definition of hypotonic (hyponatremic) dehyration?

Back 16

Serum sodium less than 130 mEq/L, happens to children who lose electrolytes in their stool and are supplemented with free water or very dilute juices

Front 17

What is the definition of hypertonic,hypernatremic?

Back 17

Na>150mEq/L
uncommon in children but implies an excessive loss of free water compared with electrolyte loss (diabetes inspidus)

Front 18

What is the usual pH of patients with dehyration?

Back 18

usually serum bicarbonate concetration is decreased secondary to metabolic acidosis

Front 19

when is the pH of patients with dehydration not acidotic?

Back 19

when patient has had protracted vommiting, results in alkalosis result of acid loss from gastric secretions

Front 20

What happens in significant dehydration? And how is this reflected?

Back 20

perfusion of kidneys may be impaired, BUN and creatinine levels elevated as GFR falls
BUN/Creatine ratio greater than 20 is consisten with prerenal failure

Front 21

What is the treatment for dehyration?

Back 21

Oral Rehydration Therapy is the prefered treatment for mild to moderate dehydration
contains 90mEq/l sodium, 20 mEq/l K, 20g/l glucose

comercial preparations: pedialyte

Front 22

What is the problem with ORT?

Back 22

Requires small volumes given very frequently, takes time, but is very effective

Front 23

What can happen with severe dehyration?

Back 23

Can lead to life-threatening hypovolemic shock

Front 24

What is the treatment of severe hypovolemic shock?

Back 24

20ml/kg iv bolus of isotonic fluid (normal saline or Ringer's lactate) until their condition stabilizes

Front 25

How are most deficits of maintance fluids replaced?

Back 25

Most given in 24 hrs, 1/2 first 8 hrs and rest over 16 hrs with the exception being hypernatremic dehdration in whom the deficit should be replaced over 48 to 72 hours to prevent excessive fluid shifts and brain edema

Front 26

How do you replace ongoing losses?

Back 26

Usually in stool, replaced milliliter for millilter with IV fluid comparable in electrolyte content with being lost

Front 27

How does the composition of the replacement fluid vary with the initial laboratory values?

Back 27

Replacement (and maintenace) fluid should be potassium free untill the patient urinates
Bicarbonate or acetate therapy may be indicated if the pH and serum bicarbonate levels remain dnagerously low after the initial boluses

Patients with profund hyperglycemia or electrolye disturbances due to underlying patholigic process (diabetic ketoacidosis) may require more specialized management

Front 28

What is the most common situation of hyponatremia?

Back 28

serium sodium level less than 130 mEq/L may occur in face of decreased normal, or increased total body sodium content most commonly dehyration, SIADH, water intoxication, Congestive heart failure, adrenal insufficiency

Front 29

What are the symptoms of hyponatremia?

Back 29

depends on level of sodium loss and the rate of change: anorexia, nasuea, neurologic findings, confusion, lethargy, decreased deep tendon reflexes, seizures, and respiratory arrest

Front 30

What is included in the laboratory workup of hyponatremia?

Back 30

serum electrolytes, glucose, blood urea nitrogen and creatine, serum osmolality, liver function tests, protein, lipid levels

Front 31

What is used for the treatment of dehyration hyponatremia?

Back 31

cautious use of 3% of hypertonic saline

Front 32

What are the signs and symptoms of hypernatremia?

Back 32

muscle weakness, irritability, lethargy, seizures and coma

Front 33

What is normal potassium values?

Back 33

3.5-5.0 mEq/L
hyperkalemia is 5.5 mEq/L

Front 34

what is the most common cause of hyerpkalemia in child?

Back 34

hemolysis of red cells, transcellular shifts in hydrogen ions increase serum potassium without changing total body content

Front 35

How does plasma potassium level change with arterial pH? what percipitates hyperkalemia?

Back 35

for every unit reduction in arterial pH, plasma potassium increases 0.2 to 0.4mEq/l

disorders and medications that interfere with renal excretion of the electrolyte precipitate true hyerpkalemia

Front 36

What are common casues of hyperkalemia?

Back 36

Acidosis
Severe dehyration
Potassium-sparing diuretics
Excessive parenteral infusion
Renal failureAddison's Disease
Renal Tubular Acidosis
Massive Crush injury
Beta-blocker or theophylline intoxication

Front 37

How does hyperkalemia present?

Back 37

early: paresthesias and weakness
late: tetany, flaccid paralysis, cardiac involvement ECG Changes, Twave peaking is followed by loss of T waves, widening of QRS complex, and ST Depression, V Fib and Cardiac arrest

Front 38

What level of potassium would lead to Ventricular Fibrilliation and cardiac arrest?

Back 38

9meq/l

Front 39

What is the treatment for hyperkalemia?

Back 39

calcium gluconate protects the heart by stabilizing the cardiac cell membrane

infusion of sodium bicarbonate or insulin (and glucose) drives potassium into the cells

cation exchange resins (Kayexlate) and hemodialysis are the only measures that actually remove potassium from the blood

Front 40

when is hypokalemia encountered?

Back 40

cases of alkalosis secondary to vomiting, administration of loop diuretics, or diabetic ketoacidosis

Front 41

what are the signs and symptoms of hypokalemia?

Back 41

weakness, tetany, constipation, polyruia, polydipsia, muscle breakdown leading to myoglobinuria and compromise renal function

Front 42

when are ECG changes noted in hypokalemia?

Back 42

levels less than or equal to 2.5 mEq/L; cardiac arrhythmias more likely when patient being treated with digitalis

Front 43

what is the treament of hypokalemia?

Back 43

correcting pH when increased and replenishing potassium stores

Front 44

how is the extreacellular fluid pH (hydrogen ion concetration) kept in a very narrow range?

Back 44

bicarbonate buffer system
hydrogen ions combine with HC03- to form H2CO3 which in turn breaks down to water and CO2 which is expired by the lungs

the addition of H+, the loss of HCO3- abnormal pulmonary function can all affect the buffering system and lead to acid-base disturbances

Front 45

how does metabolic acidosis result?

Back 45

loss of HCO3- or the addition of H+ in the extracellular fluid and is the most common acid- base disorder encountered in the pediatric population

Front 46

what formula predicts the expected PaC02 in the presence of metabolic acidosis

Back 46

PaCO2= 1.5x HC03- +8(+/-2)
if the measured PaCO2 is higher than expected than there is a primary respiratory acidosis, if it is lower than expected then there is primary respiratory alkalosis

Front 47

What is the most common clinical finding in metabolic acidosis?

Back 47

Hyperpnea

Front 48

How is the anion gap calculated?

Back 48

the difference between the sums of the measured cation (Na+ + K+) and anions (Cl- + HCO3-) normally 12+/- 4

Front 49

When is sodium bicarbonate given to patients with metabolic acidosis?

Back 49

IV administration of sodium bicarbonate is reserved for cases in which the serum pH is less than 7.0 and the cause is unknown or difficult to reverse

Patients receiving alkali thereapy require frequent pH, sodium, potassium, and calcium monitoring, complications include, alkalosis, hypokalemia, hypernatremia, and hypocalcemia

Front 50

What is contraction alkalosis?

Back 50

loss of fluid high in H+ or Cl- as may occur with protracted gastric vomiting or chronic thiazide or loop diuretic administration

Front 51

why might patients with cystic fibrosis develop metabolic alkalosis?

Back 51

due to excessive electrolyte losses in the sweat