Fluid/Electrolyte Flashcards
normal sodium lab values
136-145
normal potassium lab values
3.5-5
normal calcium lab values
9-10.5
normal chloride lab values
98-106
normal magnesium lab values
1.8-2.6
works on kidney nephrons
increases blood osmolarity, blood volume , and potassium excretion
aldosterone
released from pituitary gland
acts on kidney
reabsorbs water (retains)
ADH
secreted by ANP in response to increased blood volume and BP
opposite effects of aldosterone
urine output increase, kidney reabsorption of sodium is inhibited
natriuretic peptide
triggered when there is a change in blood indicating that perfusion is at risk (ie/ low BP)
activates angiotensin
renin
constricts arteries and veins, decreases urine output, aldosterone secretion increases
angiotensin
most common type of fluid loss problem
leads to hypovolemia and decreased perfusion
isotonic dehydration
body’s response to isotonic dehydration
body increases vasoconstriction and peripheral resistance
what is indicative of dehydration
weight loss and changes in mental status
increased HR, decreased BP and pulse
increased RR
priority during dehydration
fluid replacement (daily fluid intake should be 1500 mL)
excessive fluid in ECF space
hypervolemia
drug therapy for fluid overload (overhydration)
diuretics to remove excess fluid
who is most at risk for electrolyte imbalance
older, ill, chronic kidney and endocrine disorders
when does balance occur
when dietary intake of electrolytes matches kidney electrolyte excretion or reabsorption
major cation in ECF and maintains osmolality
sodium
where are the sodium levels high and low
high in ECF and low in ICF
regulated by kidney
influenced by aldosterone, ADH, and NAP
serum sodium
low sodium levels do what
inhibit ADH and NP and trigger aldosterone
this causes kidney reabsorption of sodium
high sodium levels do what
inhibit aldosterone secretion and stimulated ADH and NP secretion
these increased kidney sodium excretion and water reabsorption
what determines hyponatremia
sodium below 136
signs and symptoms of hyponatremia
confusion, muscle weakness, nausea, cardiac output, hypovolemia
priority during hyponatremia
prevent hypernatremia and fluid overload
therapy for hyponatremia
decrease dosage of diuretics and give IV saline (3%)
what determines hypernatremia
sodium over 145
signs and symptoms of hypernatremia
short attention span, lethargic, muscle twitching/contractions, muscles weakness, increased pulse
priority for hypernatremia
prevent hyponatremia and dehydration
therapy for hypernatremia
isotonic saline (0.9%) and dextrose 5% in 0.45 % sodium chloride
major cation of ICF
potassium
why does any change in K seriously affect physiologic activities
K levels in blood and intestinal fluid are already naturally so low
what is the main controller of ECF potassium levels
sodium potassium pump (in membranes of cells)
what is K removed by
kidney, excretion is enhanced by aldosterone
this can be life threatening because every body system is affected
hypokalemia
what is important to assess in a pt with hypokalemia
respiration status every 2 hours!
resp insufficiency is major cause of death
signs/symptoms of hypokalemia
muscle weakness, weak pulse, decreased bP, decreased peristalsis, dysrhythmia
drug therapy of hypokalemia
K is given IV
check dilution of drug (must be diluted by pharmacist)
what is severe about K
severe tissue irritant, NEVER given IM of subcut, can cause necrotic tissue
what is the maximum IV rate
5-10 m/hr (not given by push)
heart is very sensitive to what
potassium, interferes with electrical conduction
can lead to heart block and ventricular fibrillation
what are most hyperkalemia patients
hospitalized, those with abnormal kidney function
when does kidney function begin to decrease
with age
what are the MOST severe changes that occur with hyperkalemia!
cardiovascular!
bradycardia, hypotension, ECG changes
also skeletal muscle twitches and muscle weakness
priority for hyperkalemia
assess for cardiac complications, falls
how does insulin affect K
increases K movement into cells
therapy for hyperkalemia
IV fluids containing glucose and insulin
what is the active form of calcium
free calcium (must be kept within narrow range)
what does calcium do
maintains bone strength/density, activates enzymes, allows muscle contractions
when is calcium secreted
when PTH is released from parathyroid glands (inhibited if excess calcium)
what is secreted if there is excess calcium
TCT by the thyroid gland to decrease calcium levels
this is the rapid onset of life threatening symptoms
acute hyopcalccemia
signs/symptoms of hyopcalcemia
tingling, muscle cramps/spasms, icreased peristalsis, osteoporosis
BP cuff on arm for 1-4 min, watch for spasm
trousseau’s sign
tap face below and above ear, watch for twitching
chrostek’s sign
drug therapy for hyopcalcemia
direct calcium replacement and vitamin D (which enhances calcium absorption)
signs and symptoms of hypercalcemia
increased HR and BP, muscle weakness, decreased deep tendon reflex and peristalsis, observe for perfusion
what are the most severe changes that are life threatening with hypercalcemia
cardiovascular changes
what indicates perfusion
cyanosis and pallor
ASSESS temp, color, cap refill
what is given for hypercalcemia
IV normal saline (0.9% sodium chloride), given to increase kidney excretion of calcium
where is magnesisum stored
bones and cartilgae, very little in blood
more found in ICF not ECF
why is magnesium important
muscle contraction, carbohydrate metabolism, generation of energy, vitamin activation, blood coagulation and cell growth
what are the two major causes of hypomagnesemia
inadequate intake and use of loop/thiazide diuretics
what are the most important changes to watch for with hypomagnesemia
cardiovascular changes
dysrhythmias, increased nerve impulse transmission