Exam 2: Fluids and Electrolytes Flashcards
Sources of Fluid (3)
- Insensible losses
- Urinary
- Fecal
Insensible Losses
2/3rd through skin and 1/3rd through respiratory tract
Things that increase insensible loss include:
1. Increased RR
- High Fever; children can get ~105 fever, which doesn’t usually happen with adults
- Heat and humidity; In the summer, they have a higher risk of losing fluids than adults
Major Fluid Compartments (2)
- Intracellular (fluid inside cell)
- Extracellular (fluid outside cell)
A. Intravascular fluid
B. Interstitial fluid
Fluid Loss in Neonates and Young Children (6)
- Greater amount of BSA causes ↑ in insensible losses
* *This is because they have a greater proportion of their skin surface that occupies their weight
* *This increases their insensible losses
* *Child more likely to loose ECF first with fluid loss - Increased metabolic rate - ↑ fluid demand to fuel metabolic process (Due to increased demand for growth)
- Greater amount of metabolic wastes to be excreted by kidneys (Due to increase in metabolic demand)
- Glomeruli tubules & nephrons of kidney are immature & unable to conserve H2O/fluids and electrolytes effectively
- Much easier to have fluid and electrolyte loss
- Children maintain larger amounts of ECF until about 2 yrs. of age, so they are more susceptible to rapid fluid depletion
* *They have a larger proportion of their body that has fluid and it is extracellular fluid
H20 Compartment Components
75% in infants,
55-60% in adults
Under 2 years old you see that there is a larger TBW and greater proportion of ECF
Solute Compartment Components (in ECF and ICF)
ECF (Na+)
- *Main composition of ECF is Na
- *Other components in ECF: Cl-, Ca, Bicarbonate
ICF (K+)
- *Main composition of ICF is K
- *Other components: Ca, Mg, Phosphorus
Under 2 years old you see that there is a larger TBW and greater proportion of ECF
Daily Maintenance Fluid Requirements
These calculations tell us how much fluid children need to maintain their ECF:
- Weight. in kg.
- 100ml/kg for first 10 kg.
- 50ml/kg for second 10 kg.
- 20 ml/kg for remainder of wt in kg.
- Divide total amt. by 24 hrs. & obtain rate in ml/hr
- You can use this for IV fluid, oral intake, etc.
- Very imp. to ensure daily maintenance, especially in the hospital/if they are NPO
Urine Output in infants and toddlers
*Urine output can also help you see if child is dehydrated
Infants and toddlers: > 2-3ml/kg/hr
Urine Output in preschool and young school age
> 1-2ml/kg/hr
Urine Output in school age and adolescents
0.5-1ml/kg/hr
Dehydration
Classified according to serum Na+ concentration & osmolarity
*Need to know degree of child’s dehydration to dictate how and what to treat them with
Isotonic Dehydration (with causes)
Primary/most common form of dehydration in children
*When fluid and electrolyte losses are in equal proportion
Most common causes of isotonic dehydration:
- Diarrhea
- Vomiting
Fluid loss is mostly from the ECF
Greatest threat with Isotonic Dehydration
Shock/Hypovolemic shock
*would indicate there is decreased blood volume in circulation
Treatment for Mild/Moderate Isotonic Dehydration
Oral rehydration therapy (Pedialyte or Isolyte)
- This is for a child who is dehydrated and needs to be rehydrated
- Want to replace fluids and electrolytes balance while keeping their balance at an equilibrium
- Don’t give something with too much glucose, juice, salt, etc.
Serum Na level with Isotonic Dehydration
Serum Na+ (130 – 150 meq/l)
*This is a normal serum sodium because fluid and electrolyte loss is in equal proportion
Treatment for Severe Isotonic Dehydration
0.9%NS ISOTONIC IV SOLUTION
This will be for a child who is vomiting excessively and you can’t use oral rehydration
*Child will come into the hospital and get an isotonic IV solution, normally it will be 0.9%NS which is the safest for children who can’t tolerate oral rehydration
Hypotonic Dehydration (Hyponatremia) (with serum Na level)
- When electrolyte losses > H2O deficits (more water than solutes)
- ICF more concentrated than ECF
- Decreased osmolarity of blood
- Serum Na is
Causes of Hyponatremia
- Vomiting and/or Diarrhea
- Drinking a lot of water but not fluids with electrolytes in it
- *If a mother is bottle feeding, teach how to reconstitute formula adequately so that it doesn’t cause hyponatremia if there is too much water in it
- Syndrome of too much anti-diuretic hormone (SIADH)
SIADH
Syndrome of too much anti-diuertic hormone
- *Losing Na but retaining H2O
- *ADH is secreted from the pituitary, so a child may suffer from SIADH if they have a head trauma or tumor
- *Can also see it with bacterial meningitis or if patient is taking Lasix
- *If a child has these syndromes, know they are at risk for SIADH and they may need to get weighed everyday or have the sodium content in their urine checked each day
Symptoms of Hyponatremia (6)
- Headache
- Confusion
- Edema
- Hypertension
- Hyper-reflexia
- Elevated specific gravity of urine
Treatment for Minor/Moderate Hyponatremia
- Get electrolyte imbalance
- Cut back on water intake and replace with sodium
- Start correcting the imbalance with an isotonic solution
* *Always start with this because it is the safest for children
Treatment for Severe Hyponatremia
When Na level is less than 110 mEq/L
Use hypertonic solution (child will be in ICU)
*D5W, 0.5NS, or 10% Dextrose
Be very careful when infusing it and must gradually increase volume; too much too quickly can cause shrinkage of cells as extracellular fluid becomes too concentrated and then water leaves the cells to balance it
Hypertonic Dehydration (Hypernatremia) (with Na level)
- When fluid/H2O losses > electrolyte losses
- ECF more concentrated than ICF
- Serum Na >150 mEq/L