Pediatric Renal CIS: Fluid Management

Question 1

leading cause of pediatric morbidity and mortality in the world

Answer 1

Dehydration due to gastroenteritis

Question 2

The rotavirus vaccine

Answer 2

has resulted in a significant decrease in these numbers and as a result of its introduction, norovirus is now the most common cause of gastroenteritis and dehydration in the US

Question 3

3 types of dehydration

Answer 3

Isonatremic Dehydration
Hyponatremic Dehydration
Hypernatremic Dehydration

Isonatremic= sodium (Na+) concentration 130-150 mEq/L
Hyponatremic= Na+ concentration less than 130 mEq/L
Hypernatremic= Na+ concentration >150 mEq/L

Question 4

Risks of hyponatremia and hypernatremia

Answer 4

Hyponatremia-risk of protracted seizures

Hypernatremia- risks of cerebral edema, seizures and death on rehydration

Question 5

Sodium- what can it do to appearances? What is normal serum osmolarity?

Answer 5

Sodium is an osmotic particle and can create a misleading appearance to children who do not have isonatremic dehydration.

Normal serum osmolarity is 270 mOsm/kg.

Question 6

Hyponatremic dehydration - appearance

Answer 6

they may appear more dehydrated than they are as fluid moves from the extracellular space to the intracellular space resulting in clinical findings more profound than the actual level of dehydration.

Question 7

Hypernatremic dehydration - appearance

Answer 7

they may appear less dehydrated than they actually are as fluid moves from intracellular space to the extracellular space.

Question 8

Dehydration

Answer 8

Hypovolemia and dehydration occur when fluid is lost from the extracellular space. The body tries to compensate for this loss by moving fluids from the intracellular space and by releasing ADH which promotes retention of water through the renal system.

Degrees of Dehydration:
Mild 3-5%
Moderate:6-10%
Severe: greater than 10 %

Question 9

Most accurate measurement of dehydration?

Answer 9

is weight. Every gram of weight loss acutely is equivalent to 1 ml of fluid loss.
EX: 1 kilogram weight loss of a 10 kilogram baby is a 10% loss.
If you don’t have a recent weight you must rely on clinical signs and symptoms for weight loss estimate.

Question 10

Mild dehydration signs/ symptoms

Answer 10

(3-5%)

increased thirst, decreased urine, tacky mucous membranes

Question 11

Moderate dehydration signs/ symptoms

Answer 11

(6-9%)
irritable, decreased urine output, dry mucous membranes, reduced skin turgor, mildly delayed capillary refille, cool skin temp, sunken fontanelles, increased heart rate, normal to low blood pressure, may be breathing deeper

Question 12

Severe dehydration signs and symptoms

Answer 12

)10% or more)
lethargic, oliguric/ anuric, parched mucus membranes, tenting of skin, markedly delayed capillary refill, cool/ mottled skin temp, markedly sunken fontanelles, markedly increased or ominously low heart rate, low BP, deep and increased or decreased to absent breathing

Question 13

Tachycardia and Hypotension in the pediatric population

Answer 13

Hypotension is a very late finding in dehydration and if present, it represents an ominous finding!
Children compensate with heart rate first, before blood pressure changes.

Question 14

Essential laboratory test for dehydration

Answer 14

BMP and urinalysis. A BMP is a basic metabolic panel

BMP includes: Na, K, Cl, CO2, BUN, Cr, glucose and sometimes Ca.

Urinalysis includes: SG, pH, glucose, leukocytes, nitrites, bilirubin and hemoglobin.

Other labs that may be useful are a blood gas, CBC and CMP (complete metabolic panel) and a Hgb A1C

Children with mild dehydration usually do not require laboratory evaluation as we usually rehydrate orally. However, children with moderate to severe dehydration do.

Question 15

most important lab results re: dehydration?

Answer 15

CO2 or bicarb below 17 on initial evaluation implies a

significant amount of dehydration.

Question 16

Goals of Treatment of dehydration

Answer 16

To recognize the degree and type of dehydration

Restore cardiovascular stability and any water and electrolyte deficiencies while also meeting maintenance requirements and keeping up with ongoing losses.

If, based on clinical findings a child is deemed severely dehydrated, IV therapy should be instituted. Moderate dehydration usually requires IV therapy, but if closer to mild, may be able to successfully be managed with oral rehydration.

Formal assessment of fluid and electrolyte losses can be calculated. We will go through the basic science of this, however, in clinical practice it is much simpler.

Question 17

Daily loss of sodium is

Answer 17

roughly 3 mEq/100 mland roughly 2mEg/100mL for Potassium. These are lost through urination and must be replaced as maintenance.

Question 18

Daily fluid maintenance requirements are:

Answer 18

100 mL/kg/day for the first 10 kg
50 mL/kg/day for the second 10 kg
20 mL/kg/day for additional kgs

Question 19

Another way to calculate fluid maintenance: 4,2,1 rule

Answer 19

4 mL/kg/hr for the first 10kg
2 mL/kg/hr for the second 10kg
1 mL/kg/hr for the additional kgs

Question 20

Fluid Loss

Answer 20

Acute fluid losses from GE usually are 60% extracellular and 40% intracellular.
Therefore, for every 100 mL fluid loss, you lose 8.4 mEq of sodium and 6 mEq of potassium.
Na: (140 mEq Na/Lx 0.6)/10
K: (150mEq/L x 0.4)/ 10
Hyperacute losses are often completely extracellular.

Question 21

Treatment for isonatremic dehydration

Answer 21

Mild to moderate dehydration: oral rehydration may suffice- Pedialyte or Enfalyte, WHO rehydration solution

In the ED you will use these solutions. Often attempting to correct 50-100 ml/kg body weight over 2-4 hrs, if needed you can use an NG tube.

For vomiting: Ondansetron has been a very effective antiemetic in this setting or at home.

Oral rehydration is contraindicated in infants and children with cardiovascular instability, shock, altered mental status, intractable vomiting, bloody diarrhea, ileus, abnormal serum sodium or glucose malabsorption

In more significant dehydration, IV fluid may be required.

Question 22

How do we give IV fluids?

Answer 22

If clinically unstable, or showing cardiovascular compromise a bolus of fluid is indicated.
This is given in the form of 0.9% normal saline as it is made up of 154 mEq Na/L
Closely mimicks the actual osmolarity of intravascular fluid
Following a bolus or two, you can begin to give D5 ½ NS to correct the deficit and maintenance needs
In children with congestive heart failure or cerebral edema more judicious boluses may be indicated.
To correct potassium losses and provide maintenance you add 20 mEq KCl/liter after the patient has voided.

Question 23

How long do we take to correct volume IV?

Answer 23

24 hrs. One of the keys to safe mgmt of patients is to hurry to stabilize and then slow down. There is no rush once stable. Pushing too aggressively can result in complications in certain circumstances such as DKA.

Question 24

Treatment of Hyponatremic Dehydration

Answer 24

Oral rehydration is contraindicated in this circumstance.
Bolus fluids are also given as 0.9% normal saline.
If one wants to calculate the excess sodium loss that requires replacement you can use this formula:
Na+ deficit mEq = (desired Na - measured Na) x 0.6 x weight in kg.
Using the child’s baseline weight, maintenance and deficit fluid and electrolytes can be calculated and replaced over 24 hrs.
In reality, we use D5 ½ NS with 20 mEq KCl/liter as replacement fluids. Sodium should not rise more than 12-15 mEq/liter over the 24 hrs, so frequent reassessment q4-6 hrs may be necessary.

Question 25

Too rapid a correction of hyponatremic dehydration can lead to

Answer 25

a rare complication of pontine myelinosis (bleeding in the pontine nucleus). With sodium less than 120 mEq/liter you can see seizures. This can be corrected with 0.9% normal saline or 3% normal saline if too much volume is an issue. This is indeed a rare requirement.

Question 26

Treatment of Hypernatremic Dehydration

Answer 26

Because sodium draws more fluid into the extracellular space, children may appear less dehydrated than they are. Therefore you should estimate an additional 3-5% dehydration to your clinical estimate.
Patients are usually somnolent but may have a high pitched irritable cry when disturbed.

Hypertonicity can result in “brain shrinkage” and rehydration may cause too rapid an expansion of cerebral fluid resulting in cerebral edema.
This is the most common cause of iatrogenic death in DKA.

Mortality in hypernatremic dehydration can be high for 3reasons.

Patients can develop clotting in small veins or dural sinuses,
you can have tearing of vessels due to the shrinkage or
during rehydration cerebral edema.

Mortality ranges from 3-20%, neurologic sequelae up to 40-50% and of these 5-10% are severe. Infants with Na over 160mEq/L fare the worst.