FLUID & ELECTROLYTES Flashcards
Positive electroyltes
cations- magnesium, potassium, sodium, calcium
Negative electrolytes
anions- phosphate, sulfate, chloride, bicarbonate
Hypovolemia-Isotonic FVD
loss of water and electrolytes
Hypovolemia can lead to hypovolemic shock.
Dehydration-osmolar FVD
Loss of water with no loss of electrolytes.
Hemoconcentration- increased HCT, serum, electrolytes, and urine SG.
Compensatory Mechanisms- sympathetic nervous system responses of increased thirst,ADH release, aldosterone release
Causes of hypovolemia
GI losses, diaphoresis, renal losses (diuretics, DI, renal disease, adrenal insufficiency, osmotic diuresis), third spacing (peritonitis, intestinal obstruction, ascietes, burns), hemorrhage, altered intake- NPO.
Causes of dehydration
hyperventilation, DKA, enteral feeding without sufficient water intake
hypervolemia-isotonic FVE
water and sodium retained in abnormally high proportions
severe hypervolemia leads to PE and HF
decreased hct, sodium normal, decreased electrolytes, bun, creatinine
overhydration-osmolar FVE
more water gained than electrolytes
hemodilution occurs with overhydration- decreased HCT, serum electrolytes, and protein
decreased hct, decreased hemodilution, decreased electrolytes, bun, creat.
Compensatory mechanisms- increased release of naturetic peptides, increased loss of sodium and water by the kidneys and decreased release of aldosterone
Causes of hypervolemia
chronic stimulus to the kidney to conserve sodium and water (HF, cirrhosis, increased glucocorticoids), abnormal renal fx with reduced excretion of sodium and water (renal failure), interstitial to plasma fluid shifts (hypertonic fluids, burns), age related changes in cardiovascular and renal fx, excessive sodium intake
Causes of overhydration
water replacement without electrolyte placement (strenuous exercise with profuse diaphoresis)
Sodium
found in ECF
maintains acid/base balance, active and passive transport mechanisms, irritability and conduction of nerve and muscle tissue
136-145 mEq/L
Hyponatremia
less than 136. net gain of water or loss of sodium rich fluid. delays and slows the depolarization of membranes. water moves from ECF to ICF- causes cells to swell. can lead to coma, seizures, respiratory arrest.
Causes of hyponatremia
deficient ECF volume, abnormal GI losses, renal losses, skin losses, increased or normal ECF volume (increased water intake, SIADH), edematous states, excessive hypotonic IV fluids, inadequate sodium intake (NPO status), age related RF.
Hyponatremia symptoms
hypothermia, tachycardia, rapid thready pulse, hypotension, orthostatic hypotension.
Headache, confusion, lethargy, muscle weakness with possible respiratory compromise, fatigue, decreased DTR. Increased motility, hyperactive bowel sounds, abdominal cramping, nausea.
Hyponatremia tx
restrict fluids, administer hypertonic oral and IV fluids as prescribed, encourage foods high in sodium, restore normal ECF volume- administer isotonic IVF
Hypernatremia
> 145, causes significant neurological, endocrine, and cardiac disturbances. causes hypertonicity of the serum- causes a shift in water out of the cells making the cells dehydrated.
Causes of hypernatremia
water deprivation (NPO), excessive sodium intake, excessive sodium retention- renal failure, cushings, aldosteronism, meds(glucocorticoids), fluid losses-fever, diaphoresis, burns, respiratory infection, diabetes insipidus, hyperglycemia, watery diarrhea. age related changes, compensatory mechanisms- increased thirst and increased production of adh.
Hypernatremia symptoms
hyperthermia, tachycardia, orthostatic hypotension.
Restlessness, irritability, muscle twitching, muscle weakness, seizures, coma, reduced/absent DTR.
thirst, dry mucous membranes, increased motility, hyperactive bowel sounds, abdominal cramping, nausea
Hypernatremia TX
administer hypotonic IV fluids (0.45% NS), administer isotonic IVF, encourage water intake, discourage sodium intake, administer loop diuretics
Potassium
major cation in ICF, vital role in cell metabolism, transmission of nerve impulses, functioning of cardiac, lung and muscle tissue, and acid/base balance.
Has reciprocal action with sodium.
levels 3.5-5 mEq/L
Hypokalemia
<3.5, result of increased loss of potassium from the body or movement of potassium into the cells
Hypokalemia increases risk of digoxin toxicity.
Causes of Hypokalemia
abnormal GI losses- vom, suction, diarrhea, laxatives. renal losses- diuretics such as furosemide, cortecosteroids. skin losses- sweat, wounds. insufficient K, insufficient in diet is rare. prolonged administration of non-electrolyte IVF such as D5W. ICF- metabolic alkalosis after correction of acidosis, during periods of tissue repair (burns, trauma, starvation), TPN. Age related- old ppl.
Hypokalemia symptoms
hyperthermia, weak irregular pulse, hypotension, respiratory distress.
weakness with resp collapse/paralysis, muscle cramping, decreased muscle tone and hypoactive reflexes, paresthesias, mental confusion.
PVCs, bradycardia, blocks, vtach, inverted T waves, ST depression.
Decreased motility, abdominal distention, constipation, ileus, n/v, anorexia
polyuria (excess dilute urine)
metabolic alkalosis
Hypokalemia TX
replace potassium- encourage foods (avocados, brocolli, dairy, dried fruit, canteloupe, bananas), oral supplement, IV supplement- NEVER IV BOLUS (high risk of cardiac arrest), max recommended IV rate is 5-10 mEq/hr.
Hyperkalemia
> 5.0
Increased intake of K, movement of K out of the cells, or inadequate renal excretion.
Causes of Hyperkalemia
increased K form IV K or salt substitutes, ECF shift- decreased insulin, acidosis (DKA), tissue catabolism (sepsis, trauma, surgery, fever, MI). hypertonic states (uncontrolled DM). decreased excretion of potassium (renal failure, severe dehydration, K sparing diuretics, ACEIs, nsaids, adrenal insufficiency). old people.
Hyperkalemia symptoms
slow irregular pulse, hypotension
restlessness, irritability, weakness with ascending flaccid paralysis, paresthesias.
vfib, peaked Twaves, widened QRS.
n/v/d, increased motility, hyperactive bowel sounds.
oliguria.
metabolic alkalosis
Hyperkalemia TX
stop IV K, withhold oral K, K restricted diet, dialysis. Promote movement of K from ECF to ICF- fluids with dextrose and regular insulin, sodium bicarb to reverse acidosis. Loop diuretics- lasix if renal fx is adequate
Calcium
found in bones and teeth.
9-10.5 mg/dL
calcium balance is essential for proper fx of cardiovascular, neuromuscular, endocrine, blood clotting, bone and teeth formation.
Hypocalcemia causes
malabsorption syndromes- crohns, ESRD, post thyroidectomy, hypoparathyroidism, repeated transfusion.
Hypocalcemia symptoms
frequent painful muscle spasms at rest, hyperactive DTR, positive chovesteks and trosseaus sign, decreased myocardial contractility (decreased HR and hypotension), hyperactive bowel sounds, diarrhea, abdominal cramping, seizures due to overstimulation of CNS, prolonged QT interval
Hypocalcemia TX
oral or IV calcium, seizure precautions, foods high in Ca
Magnesium
most found in bones, small amount in cells, tiny in ECF
1.3-2.1 mEq/L
Hypomagnesemia
caused by malnutrition, alcohol ingestion.
s/s: increased nerve impulse transmission (hyperactive DTRs, paresthesias, muscle tetany), positive chvosteks and trosseaus. hypoactive bowel sounds, constipation, abdominal distention, paralytic ileus.
TX: dc diuretics, oral or IV mag sulfate. oral can cause diarrhea, foods high in mag- dairy, dark green veg.
