Pediatric Renal CIS: Fluid Management Flashcards
leading cause of pediatric morbidity and mortality in the world
Dehydration due to gastroenteritis
The rotavirus vaccine
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
3 types of dehydration
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
Risks of hyponatremia and hypernatremia
Hyponatremia-risk of protracted seizures
Hypernatremia- risks of cerebral edema, seizures and death on rehydration
Sodium- what can it do to appearances? What is normal serum osmolarity?
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.
Hyponatremic dehydration - appearance
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.
Hypernatremic dehydration - appearance
they may appear less dehydrated than they actually are as fluid moves from intracellular space to the extracellular space.
Dehydration
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 %
Most accurate measurement of dehydration?
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.
Mild dehydration signs/ symptoms
(3-5%)
increased thirst, decreased urine, tacky mucous membranes
Moderate dehydration signs/ symptoms
(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
Severe dehydration signs and symptoms
)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
Tachycardia and Hypotension in the pediatric population
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.
Essential laboratory test for dehydration
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.
most important lab results re: dehydration?
CO2 or bicarb below 17 on initial evaluation implies a
significant amount of dehydration.
Goals of Treatment of dehydration
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.
Daily loss of sodium is
roughly 3 mEq/100 mland roughly 2mEg/100mL for Potassium. These are lost through urination and must be replaced as maintenance.
Daily fluid maintenance requirements are:
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
Another way to calculate fluid maintenance: 4,2,1 rule
4 mL/kg/hr for the first 10kg
2 mL/kg/hr for the second 10kg
1 mL/kg/hr for the additional kgs
Fluid Loss
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.
Treatment for isonatremic dehydration
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.
How do we give IV fluids?
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.
How long do we take to correct volume IV?
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.
Treatment of Hyponatremic Dehydration
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.
