Potassium and dehydration treatment Flashcards
Daily requirement for potassium is __
2 mEq/kg/day
Hypokalemia
Definition and causes and clinical scenario
<3.5 mEq/L
- Poor intake
Anorexia nervous - Losses
- GI = V / D
- renal = RTA, diuretics, excess aldosterone
Clinical: diarrhea, muscle pain, weakness, paralysis, polyuria, –> constipation, ileus.
Hypokalemia EKG changes
Flattened T waves
ST depression
PVCs
U wave after T wave
Hypokalemia treatment
Emergency: KCl 0.5 a 1.0 mEq/L/kg over one hour. With ekg monitoring. Max 40 mEq/L.
If mild, can do oral K
If dehydrated, can just add K to MIVF
If Acidosis, use K Acetate
If low phos, use Kphos
Hypocalcemia presentation
Weakness
Prolonged QT interval
Hypomagnesemia presentation
Weakness
Diarrhea
Prolonged QT interval
Prolonged PR interval
Hypoglycemia presentation
Weakness
No EKG changes
Hyponatremia presentation
Weakness
No EKG changes
Hyperkalemia
> 5.0 mEq/L
Hyperkalemia causes
Excess intake Not enough out -renal failure -hypoaldosteronism Redistribution -acidosis (H goes into cell, K goes out) cell breakdown- pseudohyperkalemia
Hyperkalemia
EKG findings
Peaked T waves
If >10: -absent p waves -widened QRS -electromechanical dissociation (EMD) --> Muffled heart sounds and absent pulses! Tricks are IBBB and VT
Hyperkalemia tx
If >10 with EKG changes,
IV calcium chloride
Otherwise: Glucose Insulin Albuterol IV furosemide PO polystyrene resin (sodium polystyrene sulfonate)
What happens to Potassium during alkalosis?
H+ moves from IC to EC, K+ moves from EC to IC.
–>low serum K+ measured
TOTAL Body K is still the same.
Opposite is true for acidosis
5% dehydration
Clinical description
Tachycardic
Decreased tear production
Decreased UOP
Increased urine concentration
5% dehydration treatment
Need an extra 50 cc/kg
Can do this oral, or IV.
Add that to MIVF
Give half over 8hrs, 2nd half over 16 hrs
10% dehydration
Clinical picture
Tachycardia
Sunken eyes
Poor skin turgid
Sunken fontanelle
10% dehydration treatment
Need an extra 100 cc/kg
Add that to MIVF = what they need over 24 hours.
Give a 20 cc/kg bolus as needed
Whatever is left over give over 7 hrs, remainder half over 16 hrs
15% dehydration clinical picture
Same as 10% plus shock
Delayed cap refill
15% dehydration treatment
Need an extra 150 cc/kg
Add that to MIVF = 24 hr fluid requirement
Give 20 cc/kg bolus until clinical improvement.
Whatever is left over give over 7 hrs, remainder half over 16 hrs
Oral rehydration fluid
For moderate to severe dehydration
Has 75 mEq/L Na
Give 50 cc/kg over 1-4 hrs
Maintenance hydration fluids (oral)
For mild dehydration
Has 50 mEq/L Na
Can be used whenever cap refill is normalized.
Isotonic dehydration
Na 135-145
Hyponatremic dehydration
Na <135
Diarrhea
Grandmother gave kid tea or water
Usually these kids are the most symptomatic
Can present with seizures if Na <125 (water moves into brain cells)
Hyponatremic dehydration treatment
1st normal saline boluses
2nd 3% hypertonic saline in ICU
Correct fluids AND Na over 24 hrs
(Desired Na - Measured Na) x wt x 0.6 = A
Add A to maintenance Na (3 mEq/kg/day)
Hypernatremic dehydration
Na > 145
Due to water loss or Na gain
Lots of Na in ECF
Infant given improperly mixed formula
Rotavirus diarrhea
Irritable, lethargic, doughy skin, high pitched cry, seizures.
Assume 10% dehydration even if they look mild, because water is going into the ECF!
May have acidosis because cells are destroyed so H+ goes out into ECF
Brain cells shrink, can tear bridging blood vessels –> hemorrhage
Idiogenic osmoles
In hypernatremic dehydration, they replace the Na leaving the brain cells, so brain doesn’t shrink as much.
Develop over 1-2 days
Leave slowly too.
This is why we have to correct Na slowly over 2-3 days, no more than 10-12 mEq/L/day.
Also so water doesn’t rush back into brain cells (edema)
Hypernatremic dehydration treatment
Assume 10% dehydration even if they look mild, because water is going into the ECF!
Reduce Na by 0.5 mEq/L/hr if it’s chronic Hypernatremic dehydration
If Na > 170, correct over 2-3 days with 0.5 or 0.25 NS
If signs of overcorrection, use 3% hypertonic sailing as a brake to slow the correction.
Hold potassium until UOP is established.
