sodium and volume imbalances Flashcards
what is the primary determinant in ECF osmolality?
sodium
what is the primary concern of hypernatremia?
cellular dehydration
how does hypernatremia change osmolality?
make iso fluids into hyperosmotic solutions
who is most at risk for hypernatremia?
cognitively impaired or elderly clients
causes of hypernatremia due to water loss
sweating, sensible losses from high fever, sodium intake in excess of water intake, diabetes insipidus
causes of hypernatremia due to sodium gain`
IV hypertonic NaCl, sodium bicarbonate, excessive isotonic NaCl
what fluid shift occurs when IV hypertonic saline is administered?
fluid shift into the vessel (out of the cell)
what fluid shift occurs when IV hypotonic saline is administered?
fluid shift into the cell (out of the vessel)
clinical manifestations of hypernatremia
- intense thirst; dry, swollen tongue
- restlessness, agitation, twitching
- seizures/coma
- flushed skin
- weakness
- postural hypotension
- peripheral pulmonary edema
- weight loss or gain
collaborative care of hypernatremia
prevent water loss - oral fluids, IV fluids (5% dextrose or hypotonic saline) - sodium levels must be reduced gradually to avoid cerebral edema from rapid fluid shift
sodium excess - dilute sodium concentration with salt free fluids, diuretics, restricted sodium intake, I&O
what type of fluid shift occurs in hyponetremia
fluid shift from the vessel into the cells
causes of hyponatremia due to water excess
hypotonic IV solutions, common in cats after surgery, trauma CHF, polydipsia
causes of hyponatremia due to loss of sodium containing fluids
develops as body responds to fluid volume deficit: release ADH, retention of water lowers salt concentration
GI losses - N&V, diarrhea
Renal losses - diuretics, renal insufficiency
Skin losses - burns, wound drainage
clinical manifestations of hyponatremia
- irritability, apprehension, weakness and confusion
- postural hypotension
- tachycardia
- rapid, thready pulse
- jugular venous filling
- N&V
- dry mucous membranes
- weight loss or gain
- tremors, muscle spasms
- headache
what symptoms of hyponatremia manifest first?
CNS symptoms appear in the client first
collaborative care for hyponatremia
water excess - fluid restriction, small amount of hypertonic saline (if seizures occur)
abnormal losses of sodium - fluid replacement
what typically accompanies hypo and hypervolemia
at least one or more electrolyte imbalances - often associated with changes in sodium levels
what are some causes of hypovolemia?
abnormal fluid losses (diarrhea, hemorrhage), decreased intake, or a plasma to interstitial fluid shift
what are some causes of hypervolemia?
excessive intake of fluids, abnormal retention of fluids (CHF), or interstitial to plasma fluid shift
collaborative care of hypovolemia
correct underlying cause - fluid and electrolyte replacement (balanced IV solutions [lactated ringers], isotonic sodium chloride, blood replacement)
collaborative care of hypervolemia
removal of sodium and water without causing abnormal changes in electrolytes or osmolality of ECF (diuretics, fluid restriction, restriction of sodium intake
nursing management of sodium and volume imbalances
- I&O
- CV changes
- Respiratory changes: fluid excess (pulmonary congestion and edema - SOD, irritability, cough, moist crackles); fluid deficit (increased rest rate, hypoxia)
- neuro changes (changes in LOC)
- daily weights
- skin assessment (turgor and mobility, dry MM, edema - promote venous re)
an increase in 1 kg of body mass is equivalent to what?
1000 ml or 1 L
