Test 1 - Fluid and Electrolytes Flashcards
Maintenance Fluids
Holiday Segar Method
Volume per day
0-10kg - 100mL/kg
11-20kg - 1,000 mL + 50mL/kg for each 1kg > 10kg
>20kg - 1,500 mL + 20mL/kg for each 1kg >20kg
Maintenance Fluids
4-2-1 method
Hourly calculations
0-10kg - 4ml/kg/hr
11-20 kg - 40ml/hr + 2ml/kg/hr (for weight over 10)
>20kg - 60ml/hr + 1/m/kg/hr (for weight over 20)
Maintenance Fluids
BSA method
Daily and can only be used in pt >/= to 10kg
1600ml/m2/day divided by 24 hours
critically sick
1200ml/m2/day divided by 24 hours
What is the required weight to use BSA in calculating fluids?
> = 10kg
if you have a pt with increased ADH, what does that mean when you are calculating maintenance fluids
decreased fluids needed
what are 5 conditions or situations that would require a decrease in maintenance fluids
increased ADH
At risk for AKI
Ventilators, Heating or Humidification (can decrease need by 20-50%)
rule of thumb number for increased maintenance fluids needs regarding insensible fluid loss
400ml/m2/day
What electrolyte is hydration based on
Na+
isotonic fluids
NS
LR
Hypotonic fluids
1/2 NS
1/4 NS
Hypertonic fluids
3%
Colloids
Albumin 5%
Is sweating considered insensible loss
no
what labs are helpful in assessing dehydration
Serum BUN and creatinine
BMP
A pt with volume depletion without renal insufficiency may cause what changes when looking at BUN and Creatinine
disproportionate increase in BUN with little or no change in creatinine (you may not see this in pt with poor protein intake) - Nelson pg 128
A significant elevation in creatinine concentration suggests
renal injury
The urine specific gravity is usually elevated (>/= ____) in cases of significant ________
> = 1.025
dehydration
This will correct after rehydration
what may show on urinalysis in dehydration?
hyaline and granular casts
a few WBCs and RBCs
30-100 mg/dL of proteinuria
A child with dehydration has lost water; there is usually a concurrent loss of ___ and ___
Na+
K+
when can you add potassium to IV fluids
After they void, unless significant hypokalemia is present
A pt with diarrhea who has been replacing with only water or has been receiving diluted formula is at risk for what type of dehydration
hyponatremic dehydration
What is considered overly rapid correction for hyponatremia and Hypernatremia and what does overly rapid correction put the pt at risk for
> 12mEq/L per 24 hours
Hyponatremia - Central pontine myelinolysis
Hypernatremia - cerebral edema
A pt with dehydration secondary to lack of access, poor thirst mechanism (neuro), intractable emesis or anorexia is at risk for what type of dehydration
Hypernatremic dehydration
symptoms of Hypernatremic Dehydration
Lethargy irritable fever hypertonicity hyperreflexia seizures
rapid correction of Hypernatremic Dehydration can cause
Cerebral edema
symptoms of cerebral edema
Headache
AMS
seizures
brain herniation
Oral rehydration guidelines using Oral Rehydration solution that contains glucose and electrolytes
50mL/kg within 4 hrs for mild dehydration
100mL/kg within 4 hrs for moderate dehydration
Additional 10mL/kg for each diarrhea stool or emesis
Maintenance of 100mL of ORS/kg in 24 hours until diarrhea stops
Breastfeeding or formula feeding should be maintained and not delayed for more than 24 hours
Normal Na+
135-145
Na+ and ____ follow each other
H20
isotonic fluid that contains K+
LR
Symptoms of hyponatremia
Nausea/anorexia/vomiting malaise/lethargy confusion/agitation headache seizures decreased reflexes coma
may develop cheyne stokes respirations, muscle cramps and weakness
(brain cell swelling is responsible for most of the neuro symptoms)
more severe with rapid onset of
formula to correct hyponatremia
0.6 x kg x (target Na - measured Na)
use Hypertonic (3%) which has 500mEq Na+ /L
Raise 2-4 mEq/L in 4 hours or (10-20 q 24 hours)
If seizing, Goal is to bolus for quick to 125. Then slow correction over 24 hours
what are the 3 types of hyponatremia
Hypovolemic
Euvolemic
Hypervolemic
type of hyponatremia where child has lost sodium from the body. Water balance may be positive or negative but there is a higher net sodium loss than water loss
hypovolemic hyponatremia
hyponatremia and no evidence of volume overload or volume depletion has _________ _______> These patients typically have an excess of total body water and a slight decrease in total body sodium
euvolemic hyponatremia
In SIADH what type of hyponatremia do we see
euvolemic hyponatremia
What type of hyponatremia is there an excess of total body water and sodium, although the increase in water is greater than the increase in Na
Hypervolemic hyponatremia
labs to follow for Hyponatremia
Serum Na
Serum Osmols
Urine Osmols
causes of Hypernatremia
Excessive Na intake
Inappropriately concentrated formula
Excessive free H20 loss: Breastfeeding failure, diarrhea, DI
Symptoms of Hypernatremia
Weakness lethargy decreased deep tendon reflexes irritability muscle cramps renal failure AMS Seizures
Formula for correcting Hypernatremia if hypovolemic
If hypovolemic, calculate free water deficit
0.6 x kg x (current Na / desired Na) - (0.6 x kg)
correct over 24 hours
usually 1/2NS or 1/4 NS and may change
normal K+
3.5-5.2
Acidosis causes K+ to
increase
Alkalosis causes K+ to
decrease
Potassium is excreted by
kidneys
What EKG changes occur with increasing severity of hyperkalemia
Normal EKG
Peaked T waves
Wide PR interval with Wide QRS duration and Peaked T waves
Loss of P waves and sinosoidal waves
Hyperkalemia causes
Acute or chronic renal failure Tissue injuries (crush injuries) Hemolysis Acidosis Medications (Spironolactone, Bactrim, Ace inhibitors)
What medications can cause Hyperkalemia
Spironolactone
Bactrim
Ace inhibitors
Peaked t waves, prolonged PR and QRS EKG changes are a precursor to
V. Fib
How can you treat hyperkalemia
Calcium Chloride Sodium Bicarb D25/50% with insulin Kayexalate Albuterol
Where is the majority of magnesium stored
in bones
<1% is extracellular
What is magnesium important for
ATP generation
DNA transcription
membrane stabilization
regulation of K excretion
Normal magnesium levels
1.7-2.2
causes of hypomagnesemia
GI losses Vomiting Diarrhea Refeeding syndrome Pancreatitis IBD celiac disease CF Hypercalcemia diuretic use RTA DM DKA Hyperaldosteronism
symptoms of Hypomagnesemia
Anorexia
N/V
Seizures, Ataxia, hyperreflexia
EKG changes: Torsades de pointes, Long QT
Diagnostic eval hypomagnesemia
Mg level
iCal
EKG
Management of hypomangesemia
Repletion with Mag sulfate or Mag chloride
Consider K repletion
Chloride has a direct relationship with
sodium
Chloride has an inverse relationship with
bicarb
what causes hypochloremia
CF
Bulimia
Diuretic usage
Presentation of Hypochloremia
rarely occurs by itself (usually hypernatremic as well) Arrhythmias decreased resp effort seizures tachycardia
treatment of Hypochloremia
Find cause
Replace with K, Na or ammonium chloride, or arginine chloride - based on other electrolyte levels
Hyperchloremia causes
diarrhea
Chloride administration
metabolic acidosis
presentation of hyperchloremia
Often no symptoms Kussmaul respirations lethargy headache confusion
Treatment hyperchloremia
Find underlying cause
treat acidosis: can use sodium bicarb
what can cause hypophosphatemia
refeeding syndrome DKA severe resp alkalosis vit d deficiency burns
symptoms of hypophosphatemia
impaired energy utilization
diaphragmatic/resp muscle weakness
tissue hypoxia
how to treat Hypophosphatemia
IV phos repletion
causes of hyperphosphatemia
renal failure
phosphate containing enemas (fleet enemas)
Tumor lysis syndrome
how to treat hyperphosphatemia
phosphate binders
mannitol
diuresis
Calcium is found in what 3 forms
Bound to albumin (plasma protein)
Diffusible (CaCitrate or CaPhosphate)
Unbound ion
Ca+ levels
9-10
iCal hypocalcemia
<1.1
Causes of hypocalcemia
post PRBC infusions hypoparathyroidism sepsis tumor lysis DiGeorge syndrome
symptoms of hypocalcemia
Neuromuscular irritability confusion muscle cramps numbness tingling Cardiac: prolonged QT, AV blocks, sinus tachycardia
cardiac changes seen in hypocalcemia
Prolonged QT
AV blocks
Sinus Tach
Diagnostic eval for hypocalcemia
Ca level (total and iCal)
CMP
PTH
EKG
Acute repletion for hypocalcemia if symptomatic
Calcium chloride - 10-20 mg/kg/dose
Calcium Gluconate - 100mg/kg/dose
Causes of hypercalcemia
Williams syndrome
excessive intake
immobility
malignancy
Presentation of hypercalcemia
nausea anorexia constipation lethargy headaches seizures arrhythmias
Diagnostic for hypercalcemia
total cal
iCal
PTH
EKG
Treatment for Hypercalcemia
Hydration
loop diuretic for diuresis
Calcitonin for rapid correction
what does LR contain that the other fluids do not
K Ca, HCO3 and sodium lactate
How much Na and Cl is in NS (g/L)
1/2 NS
1/4 NS
154 and 154
77 and 77
34 and 34
3% 513 and 513
LR has 130Na and 109 CL along with 4K and 28 bicarb
what fluid choice has the highest and the lowest mOs ml/L
3% NS with 1027 mOs ml/L
1/2 NS with 154 mOS ml/L
Fluid deficit formula
Pre-illness weight - illness weight
ECG changes associated with hypokalemia
Flat or absent T waves
Long QT
Prolonged QRS
Presence of U waves
symptoms of Hypokalemia
Diastolic dysfunction cramping fatigue ileus often asymptomatic check mag - prob low as well
diagnose Hypokalemia
BMP with Mag level
Urine studies, osmols
Management of hypokalemia
Identify cause - are they on a diuretic that is dumping k
Potassium repletion - KCL 0.5-1meq/kg/dose
EkG changes seen in Hypomagnesemia
Torsades de Pointes
Long QT
causes of hypermagnesemia
excessive intake of Mg containing laxatives or antacids
Chronic renal failure
tumor lysis
Presentation of hypermagnesemia
Hypotonia
decreased reflexes
hypotension
flushing
Management of Hypermagnesemia
Stop any mag intake fluid for volume expansion inotropes for BP management Vent assistance for muscle weakness For rapid removal, dialysis can be used or exchange transfusion
is Cl acidic or basic
acidic
