Fluids And Electrolytes Flashcards
Total body water (TBW)
Water main component
TBW divided into intracellular water (ICW) and Extracellular water (ECW)
TBW decreases with advancing GA
First trimester - 90% of body weight
32 weeks - 80%
Term - 78%
5th month - term mostly extracellular
Age 1 - 60-65% (mostly intracellular)
Osmolality
Water’s relative content of solutes (electrolytes and proteins)
Main extracellular ion
Sodium
Regulated by kidney
Main intracellular ion
Potassium, regulated by sodium potassium cellular pump
Sodium
Major extracellular ion
Makes up 90% of total solutes in extracellular compartment
Premies dump sodium so need higher levels in bag
Potassium
Major intracellular cation
Initiates and maintains muscular contraction in cardiac and skeletal muscle
3.5-5.5
Chloride
Extracellular, works with sodium to maintain plasma volume (holds onto water)
Normal - 96-111
Low chloride and high bicarbonate - alkalosis
High chloride and low bicarbonate - acidosis
Calcium
Most abundant mineral in human body
Important for muscle contraction, neural transmission, and blood coagulation
8.8-10.3
Phosphorus
85% is in skeleton
Remaining is in soft tissues and extracellular fluid
Good for bone strength, erythrocyte function, cell metabolism, and generation and storage of energy
Milk fortification
Magnesium
Energy production, cell membrane function, and protein synthesis
1.6-2.4
Trace minerals
Zinc and copper
Zinc
Accumulated mostly in 3rd trimester
Metabolism
Copper
Adequate stores in liver for both preterm and term
Weight loss week 1 of life
5-10% in term
10-20% in preterms
Potassium in 1st DOL
Shifts from intracellular to extracellular, can rise
As renal excretion occurs will decrease
Glucose in first DOL
Decreases 60-90 minutes after birth
Once they hit low, this trigger glucogenesis ( but premies don’t have glycogen stores)
Calcium in first DOL
Abrupt stop in maternal supply, plasma will drop and reach nadir 24-48 hours after birth
PTH increases which mobilizes calcium from bone (if hypocalcemic, result of sluggish PTH response)
If lower albumin and acidosis occurs, can result in lower calcium in plasma
Highest loss of fluid
Urine
Body weight
1 gram of weight = 1 ml of fluid
Normal UOP
2-4 ml/kg/hr
Urine specific gravity
Normal is 1.008-1.012
Early indication of hydration status
If high - dehydrated and need fluid
If low - too much fluid and diluted
Used in premies because kidneys are immature and can’t concentrate tribe well
Proteinuria
Sign of dehydration
Hematuria
Renal vein thrombosis
BUN
Blood urea nitrogen
7-20
High or rapid rise indicates some degree of renal failure
Creatinine
0.8-1.4
More reliable than BUN
Levels mimic mom at birth
0.2-0.5 per day increase indicates renal failure
Fractional excretion of sodium (FENa)
Determines kidney damage vs volume issue
Premie body fluid composition
85-90% water
1/3 intracellular
2/3 extracellular
Insensible water loss
Due to increased permeability of skin
70% from skin
30% from respiratory tract
Average loss 10-60 ml/kg/day
Insensible water loss results in
Hypernatremia, dehydration, loss of heat
Phototherapy and water loss
Can increase, should increase fluids if on photo
Dehydration can result from
GI losses
Acute blood loss
Medications (caffeine)
Low protein (albumin) can cause
Overhydration/edema/third spacing
Over hydration puts baby at risk for
PDA
IVH
BPD
If metabolic acidosis occurs…(K)
Potassium shifts from intracellular to extracellular
Increases potassium
If metabolic alkalosis occurs (K)…
K shifts from extracellular to intracellular, lower K
DiGeorge (chromosomal deletion at 22)…electrolytes
Hypocalcemia due to atresia or hypoplasia of parathyroid gland
Murmur due to cardiac issues
Facial anomalies
Phenytoin (seizures) and Lasix…
Reduces diuretic response to Lasix
Too much fluid can cause…Na
Hyponatremia, high UOP
EKG with hypoK
Flattened T waves
EKG with hyperK
Peaked T waves
NEC sign (Blood gas)
Persistent metabolic acidosis (lower ph and bicarbonate)
NEC causes lactic acidosis secondary to necrotic bowel
Diabetes insipid is
High Na and high UOP
High Na and low UOP
Insufficient intake
Calcitonin
Decreases calcium
Perinatal asphyxia and stress can cause increase in this
High K in preterms, first line treatment
Insulin glucose infusion
Insulin causes K to enter cells
Glucose is to avoid hypoglycemia associated with giving insulin
Intestinal ileus associated with low…
K
