Dehydration Flashcards
What is maintenance fluid
Volume of daily fluids needed to replace insensible water loss (stool, urine, evaporation)
What are the components of maintenance fluid?
- Na
- K
- water
- glucose
Is maintenance fluid rich in calories or not?
No, patient on maintenance fluid lose 0.5% to 1% of their weight
What is the goal of maintenance therapy?
Prevent:
- dehydration
- electrolyte Disorders
- ketoacidosis
- protein degeneration
What is the commonest method to use for calculating maintenance fluid
Holliday segar method
What is the most accurate way to calculate maintenance fluid?
Body surface area
Used in renal failure\oncology
How does the caloric expedenture method work?
The amount of calories needed= amount of fluids given
How to preform the holiday-segar method on fluid?
First 10Kg: 100ml\kg\d “4ml in hr”
Second 10: + 50ml\kg\d “2ml in hr”
Third 10: +20ml\kg\d “1ml in hr”
How to preform the holiday-segar method on electrolyte?
- Na: 3meq\100 ml “range of 2-4”
- K: 2meq\100ml
What are the available IVF for hydration
- normal saline (0.9Nacl - half - quarter)
- ringer lactate (balanced)
What is the Na and cl values in 0.9Nacl
154
Then for the half (you half)
Then for the quarter (you half\half)
What is the Na and Cl and K concentration in ringer lactate
Na: 130
Cl: 109
K: 4
In hospitalized patient, what can we use from the following solutions?
- 0.9NaCl
- 0.45 NaCl
- 0.2 NaCl
0.9 and 0.45 but not 0.2
Change in urine (by renal failure) or stool by (enterostomy\colestomy) changes the maintenance fluid in that it:
Will make us eliminate it from the insensible water loss
“Urine 60%, evaporation 35%, stool 5%”
Who shows signs of dehydration first, infant or older children?
Older children due to low ECF
What happens to ECF as infant gro
Decreased
Why are younger children more susceptible to dehydration?
1- large body water content
2- renal immaturity
3- inability to meed their needs “breastfed”
How does Cystic fibrosis cause dehydration?
Due to the increased sweating
What are the 3 questions to ask in dehydration assessement?
1- how much
2- how fast
3- what route
How much is the dehydration is answered by:
Severity (weight loss - clinical mainfestations)
“%: preillness weight - illness weight\peillness weight X 100”
What is the percentage of dehydration, for mild, moderate and severe?
In infant <10kg
Mild: 5%
Moderate: 10%
Severe: 15%
What is the percentage of dehydration, for mild, moderate and severe?
In children >10kg
Mild: 3%
Moderate: 6%
Severe: 9%
How to measure the deficit of dehydration assessment
The percentage of weight loss X 100 X Kg
Concentrated urine indicates
Moderate to severe dehydration
What will you obtain from the dehydration history?
1- weight loss 2- intake of fluid\appetite 3- urine output 4- stool output 5- emesis 6- activity level 7- underlying illness
What’s the benefit of asking about emesis if it’s not associated with dehydration
It will determine if it’s oral intake or IV
What is the capillary refill for mild moderate and severe dehydration
Mild: 2sec
Mod: 2-4sec
Severe: >4 sec
What is the mucus membrane in mild, moderate and severe dehydration
Mild: normal
Mod: dry
Severe: parched and cracked
Tears in severe dehydration is
Absent
What is the BP in moderate dehydration
Normal but orthostasis
Thready pulse is characterstic for which scale of severity?
Moderate.
Severe is faint or impalpable
A common finding in examination of skin in severe dehydration is called
Tenting
Sunken fontanelle indicate
Severe dehydration
Name the 3 signs that are most predictive of moderate to severe dehydration
1- prolonged capillary refill
2- delayed skin turgor
3- increase respiratory rate
Labratory investigations in dehydration:
- Serum Na
- blood gas
- BUN\creatinine
- urine analysis
- potassium
- HCT
What is the creatinine\BUN ratio that indicate dehydration instead of renal failure?
20:1 anything less than this is renal failure
What are the findings in moderate to severe dehydration in blood gas?
Metabolic acidosis w\low HCO3 meq
Potassium is indicated in the workup for dehydration because it’s associated with
Gasteroenteritis
What are the finding of urine analysis in dehydration
High specific gravity
Low sodium
What is HCT in dehydration?
Hight
How to answer the how fast question in dehydration?
According to the type
“Plasma Na level”
Major determinant of serum osmolality is
Sodium “as long as there is no renal failure”
Differentiate isonatermic, hyponatermic, and hypernatermic dehydration
130-150
More is hypernatermic, less is hypo
What happens to the cell in hypo vs hypernatermic dehydration?
Hypo: swells
Hyper: shrink
Differentiate between clinical presentation of hyponatermic and hypernatermic:
Hypo: cold, clammy skin, lethargy
Hyper: irritble, doughy, BP elevated
Both seizures
Doughy skin is associated with
Hypernatermia
What is the best route for rehydration? “Mild to mod”
Oral
“Lower cost, no need of IV, done at home”
What is ORS composed of “solutes”?
1 glucose 2sodium
How to make ORS?
1l water + 6 ts sugar + 1\2 ts salt + 1\4 ts baking soda
How long should ORT be given?
Over 4 hours in small volume
What are the contraindication of ORT?
Severe dehydration - altered mental state - intestinal ileus - severe electrolyte imbalance - care giver can’t provide ORT
What happens in hypotonic dehydration and when it’s treated rapidly
- hypotonic: swelling of the cell in the brain (edema)
- treatment (rapid): shrinkage leasing to osmolar demylination (central pontine myelnolysis)
