fluid and electrolytes Flashcards
(110 cards)
Na/K pump: what & how
what: active transporthow: Na out / K in
Na function x3
- skeletal + cardiac muscle contraction- nerve impulse transmission- water balance (where Na goes, H2O follows)
- free H2O replenishment quantity calculation
[0.6 x wt (kg)]x[(measured Na/140) -1]
individuals at risk for electrolyte abnormalities
- elderly- altered renal function- Acute/chronic renal disorders- Acute/chronic endocrine disorders- SIADH, DM- Mentally impaired- unable to access fluids- meds that alter fluid/electrolyte levels- all hospitalized patients
thiazide diuretic site of action
distal convoluted tubule
loop diuretic site of action
thick ascending limb
aldosterone site of action
collecting duct
hypernatremia is…
↓ H2O : Na in ECF = ↑ total body Na / ↓ total body H2O↓ intracellular fluid volume because H2O drawn out of cells
acute water deficit rate of correction
1 mMol/hr
chronic water deficit rate of correction
0.5 mMol/hr
hypervolemic hypernatremia is
change in net body soluted/t…hypertonic saline or Na bicarb infusionskayexalate therapy (sodium polystyrene sulfonate)
hypervolemic hypernatremia tx
diuretics w fluid replacement- free H2O- D5Wtreat the cause
hypovolemic hypernatremia is
↓ body H2O + Nabut losing more H2Od/t…insufficient H2O intake: lt 600-700 ml/day loss of free H2O: excessive sweating, GI loss, osmotic diuresis
hypovolemic hypernatremia tx
NS 0.9%- LOSING Na AND H2Omay need add’l fluids to meet needs: free H2O, D5W
isovolemic hypernatremia is
↑Na, body H2O appropriated/t…inability to concentrate urineappropriate free H2O w/o Na excretion↑ serum osmolality (hyperglycemia, mannitol)
isovolemic hypernatremia tx
diuretics w fluid replacement- free H2O- D5Wtreat the cause
results of hypernatremia x4
↑ Na movement @ depolarization, = ↑ excitability/irritabilityH2O drawn osmotically out of cells = intracellular dehydration↓ intracellular fluid vol CNS: H2O shift brain interstitium → capillaries = cerebral atrophy
hypernatremia: clinical signs
neuro- early: lethargy, weakness, irritability - later: twitching, seizures, coma, deathgeneral- dry/sticky mucosa- ↑ body temp (no fluid buffer for metabolic processes)- thirst
hyponatremia is…
↑ H2O : Na in ECF = ↑ total body H2O ECF more dilute than ICF↓ excitable membrane depolarizationcellular swelling
hyperosmolar hyponatremia is
↑ body concentration w ↓Na- ↑ intravascular oncotic P (hyperglycemia, mannitol)- ICF → extracellular space- ↓ TBW- altered urine Na excretion– low - typical, Na retention appropriate—- d/t → extrarenal loss (GI, skin)– normal/high—- d/t → renal loss (diuretic [thiazide], adrenal insufficiency, Na-losing nephropathy)
hypoosmolar hyponatremia types x3
hypervolemichypovolemicisovolemic
isosmolar hyponatremia is…
LESS COMMON usually d/t lab errorNa conc displaced w/o change in TBW contentmachine mistakes the following for electrolytes that don’t exist:- hyperlipidemia- hyperproteinemia- hyperglycemiafix apparent issues above before addressing Na (may be artifactual)
isosmolar hyponatremia tx
determine urgency of replacement: acute onset, Na
hypernatremia vs hyponatremia: difference between the types
hypernatremia: r/t volumehyponatremia: r/t osmolarity