Fluid and Electrolytes Part 2 Flashcards
what is one of the biggest causes of electrolyte abnormalities?
diuretics
what abnormality can occur from RBC lyses
pseudohyperkalemia
no need to treat
If you have hypoalbuminemia, what else will it look like?
hypocalcemia
How should you not administer K+?
No bolus of IV doses
infusion rate to not exceed 10-20 mEq/hr
limitations on concentrations for peripheral infusion
When can you only use IV calcium?
cardiac symptoms for hyperkalemia or hypermagnesia
low serum concentration can occur with ______ syndrome. may need to add high than standard doses to PN and glucose containing IV.
refeeding syndrome
High serum concentrations can occur in _______ __________, use reduced doses in PN and IV fluids
renal failure
what 2 elements can mix and form a precipitation?
calcium-phosphorous
when is there an increased risk for calcium-phosphorous precipitates?
sodium biacarb when treating hyperkalemia
infusions of calcium or phosphorous
what drugs can cause hyperkalemia?
K+ sparing diuretics
ACEI, NSAIDs
Beta antagonists
pseudohyperkalemia (lysis of RBC during collection)
What drugs can cause hypokalemia?
diuretics (except K+ sparing)
insulin, refeeding syndrome, treatment of DKA
Beta agonist, glucocorticoids
ampho B, aminoglycosides
what do insulin do to potassium?
forces potassium into cell
what drug can cause hypermagnesemia?
lithium
what drugs can can cause hypomagnesemia?
Diuretics Amphotericin B, aminoglycosides Cyclosporin, alcohol Digoxin Laxative abuse Refeeding syndrome
drugs that can cause hypercalcemia
thiaizde diuretics
lithium
Vit A and D toxicity
calcium
what drugs can cause hypocalcemia?
Loop diuretics
oral phosphorus
phenytoin, barbituates
vit D deficiency
what can cause hyperphosphatemia?
phosphate-containing enemas
IV phosphorous to tx hypercalcemia
what can cause hypophosphatemia?
diuretics insulin, dextrose, refeeding syndrome tx of DKA sucralfate antacids calcium salts
Electrolyte abnormalities with an acute onset may have more ______ ___________ and should be treated more aggressively
more severe
how is potassium bound?
intracellularly, so serum K+ not a good measure of total body potassium, but do correlate w/ symptoms
symptoms of hyperkalemia?
cardiac abnormalities (ventricular fibrillation, asystole, ECG- peaked T waves) muscle abnormalities- weakness, paralysis
causes of hyperkalemia?
increase potassium intake
decrease potassium excretion
potassium release from intracellular space
tx approach for hyperkalemia
Antagonism of K+ if cardiac abnormalities exist
Promote intracellular redistribution
Remove K+ from the body
if cardiac symptoms are present w/ hyperkalemia what should you administer?
IV calcium gluconate give over 5-10 minutes and repeat every 30-60 minutes until ECG normalizes
does IV calcium gluconate reduce or redistribute serum K+
no, only restores normal conduction of heart
what is the first therapy for hyperkalemia (intracellular redistribution) if patient isn’t acidotic
regular insulin
onset of 30 minutes (duration 2-6 hours)
If a patient isn’t hyperglycemia and is hyperkalemic what do you give?
Dextrose with insulin
D10W 1 L over 1-2 hours
D50W, 50 mL over minutes
what does insulin promote?
cellular uptake of K+
2nd line therapy for hyperkalemia. Give if patient is acidodic.
Albuterol high dose nebulized of 10 minutes (10-20mg)
onset is 30 minutes, duration of 1-2 hours
what drug do you only use when hyperkalemia is due to acidosis?
Sodium bicarb IV over 2-5 minutes
onset 30 minutes, duration 2-6 hours
what should you not infuse sodium bicarb through
same IV lines as parenteral nutrition, or other calcium and phosphorous solution
what is a tx for hyperkalemia that removes K+ from the body
furosemide IV (if normal renal function)
sodium polystyrene sulfonate (oral route better)
hemodialysis
what drug exhcanges Na+ for K+ and removes K+ from the body
sodium polystyrene sulfonate
oral route is better tolerated
S/S of hypokalemia
flattened T waves, presence of U waves
bradycardia, PVCs, heart block, a-flutter/ v-fib
myalgia, muscle weakness, cramps, paralysis
causes of hypokalemia
GI losses (V/D, NG suction) inadequate K+ intake alkalosis
Meds that cause hypokalemia
B2 agonists, insulin
loop and thiazide diuretics
high dose abxs (PCN)
AmphoB< foscarnet- depletion of mag diminished K+ intracellularly
when should you tx hypokalemia?
low serum K+ if patient symptomatic cardiac condition that predisposes to arrhythmias receiving digoxin therapy consider w/ patients on diuretics laxative abuse any patient w/ serum K+ <3.0 mEq/L
Non-pharm tx for hypokalemia
some salt substitutes
dietary sources (fruits, veggies, meats)
dietary is usually in potassium phosphate form (potassium chloride is most often administered)
need to also consider replacing chloride in diuretic therapy, vomiting, diarrhea
how is oral Potassium available
K+ chloride (more common)
K+ phosphate- (use if both are depleted)
K+ bicarb (if patient acidodic)
is oral or IV potassium better
oral, IV has risk of death
when do you consider IV potassium?
oral route not feasible or life threatening symptoms
Administered over 1 hours- NO BOLUS
infusion to not exceed >10 (if needed monitor ECG)
when do you need to monitor potassium with IV infusion
serum concentrations after 30-40 mEq
what type solutions should you avoid w/ IV potassium?
dextrose containing solution (promotes insulin release)
what is the 2nd most abundant ICF cation?
magnesium
what do mag do?
provides neuromuscular stability
involved in MI contraction
is magnesium part of a normal Chem 7?
no, need to order separately
symptoms of hypermagnesium?
muscle weakness, neuromuscular blockade (paralysis) respiratory muscle paralysis calcium channel blockade HYPOTN sinus brady, asystole
what is a big cause of hypermagneisum
renal failure in conjunction w/ meds that have magnesium (cathartics, antacids, magnesium supplements) lithium therapy (!!)
hypermagnesemia tx?
DC all mag supplements or mag-containing meds
give elemental calcuim 100-200 mg IV (antagonizes neuromuscular and CV effects) requires repeated doses
Loop diuretics (furosemide) and saline if normal renal function
hemodialysis if renal dz
what may be needed for a extreme cardiac symptoms w/ hypermagnesium
vasopressors
cardiac pacemakers
Signs of hypomagnesemia
Neuromuscular- tremor, seizures, tetany/ hyperreflexia
Cardiac- tachy, v-fib, torsade de pointes.
EKG- prolonges QRS, increased PR interval and QT interval
clinical presentation of hypomagnesemia?
metabolic alkalosis
hypocalcemia
digoxin toxicity
(strong relationship b/w hypo-K+ and hypo-Mg)
Causes of hypomag
inadequate intake (ETOH) inadequate absorption (steatorrhea, cancer, malabosprtion, excessive Calcium) Excessive GI/ urinary loss
what meds can cause hypomag?
Aminoglycosides, amphoB, cisplatin, insulin, loop and thiazide diuretics, cyclosporin
tx for hypomag?
IV route if severe and symptomatic, PO if mild
how do administer IV Mag sulfate
avoid rapid bolus injection (flushing, sweating)
dilute administer to avoid pain and venosclerosis
only use IM if peripheral access not available
need to gradually replace deficit over days
what is a major problem w/ IV mag?
kidneys clear 50% of it right away
may need to giver higher doses
what is the main limiting factor of oral magneisum admin?
diarrhea
what does calcium help with?
nerve impulses skeletal muscle contraction myocardial contractions maintenance of cellular permeability and formation of bones and teeth will bind w/ phosphate 1/2 protein bound and 1/2 free ionized
what happens w/ acute hypercalcemia
Inability to concentrate urine
Acute renal failure
Coma
Ventricular arrhythmias
symptoms w/ chronic hypercalcemia? (more likely)
Metastatic calcification
Nephrolithiasis
Chronic renal insufficiency
what can cause hypercalcemia?
hyperparathyroidism malignancy paget's dz granulomatous dz (TB, sarcoidosis) hyperthyroidism immbolizilation (multiple bony fracture)- acute acidosis
what meds can cause hypercalcemia? (more chronic picture)
thiazide diuretics, estrogens, lithium, tamoxifen, Vit A, Vit D, calcium supplements
if a patient has life-threatening symptoms w/ hypercalcemia and functioning kidneys what do you do?
saline rehydration loop diuretics hemodialysis calcitonin glucocorticoids IV PO4 if low
how to tx hypercalcemia w/ life-threatening symptoms and renal failure
hemodialysis
calcitonin
glucocorticoids
with non-lifethreatening symptoms and hypercalcemia how do you treat?
saline rehydration loop diuretics calcitonin glucocorticoids IV bisphosphonate mithramycin
if a patient is asymptomatic and has hypercalcemia what do you do?
observe
correct reversible cause
(often an endocrine disorder)
what can help if a patient has hypercalcemia that leads to vomiting and inability to concentrate urine.
NS rehydration therapy
helps improve volume status
once patient is rehydrated and has hypercalcemia what can you do?
Loop diuretics (inhibits Ca@ reabsorption from ascending LOH)
prevents volume overload
monitor for hypokalemia and hypomagnesia
what is a tx for hypercalcemia that interferes w/ Vit D. add to calcitonin to prolong effect
prednisone (glucocorticoid)
why can’t you use phosphates to treat hypercalcemia?
crystals may precipitate in tissue
if a patient has hyperparathyroid dz and hypercalcemia what can you use?
oral phosphates
what are good long term therapy options for hypercalcemia?
glucocorticoids
bisphosphonate
Hypoalbuminemia decreases total calcium concentrations but _________ may be normal
ionized (i.e. free calcium)
what is the formula for correct calcium for patients with a low albumin level
serum calcium + 0.8(NL albumin- Pt’s albumin)
or you can draw a free calcium
what are symptoms of hypocalcemia?
neuromuscular- tetany, muscle cramps
CV- HPOTN, decreased contractility, HF
seizures, areflexia
(can be seen in rickets and osteomalacia)
what conditions can cause excess losses of calcium?
hypoparathyroidism
renal failure
alkalosis
pancreatitis
what meds cause hypocalcemia?
Phosphate replacement products, loop diuretics, phenytoin, phenobarbital, corticosteroids, aminoglycosides
how do you treat hypocalcemia if acute symptomatic?
Bolus with 100 to 300 mg of elemental calcium IV over 5 to 10 minutes
continuous infusion
monitor serum calcium every 4-6 hours
what rate must you not exceed w/ IV calcium to avoid cardiac ADRs
Rate NTE 60 mg/min
what form of IV calcium causes less phlebitis
calcium gluconate
what form of calcium has a better correction of calcium (but more painful infusion)
calcium chloride
where is phosphorous found?
bone, ICF, ECF
what are signs of hyperphosphatemia (usually due to ypocalcemia)
crystals develop in joints, soft tissue, kidney
Crystal formation is likely to occur when product of the serum calcium and phosphate concentrations exceed _____-____
50-60
what are causes of hyperphosphatemia?
renal failure, hypoparathyroidism redistribution to ECF (acid-base imablance, rhabdo, tumor lysis during chemo) increased intake (enemas, Vit D supplements, bisphosphonates)
how do treat severe s ymptomatic hyperphosphatemia?
IV calicum salts
tx for less severe hyperpohsphatemia?
oral phosphate binders (decrease GI absorption)
exs- Ca, Mg, Al salts
clinical presentation of hypophosphatemia
seizures
muscle weakness (diaphrgam muscle and fatigue)
decreased cardiac contractility
skeletal muscle weakness
what are causes of hypophospatemia?
increased distribution to ICF (insulin therapy, malnutrition)
decreased absorption
increased renal loss
what meds cause hypophosphatemia
Diuretics, antacids, foscarnet, phenytoin, phosphate binders, calcium acetate
what must you consider w/ hypophosphatemia treatment?
figure out cause
if DKA, glucose infusion, refeeding, alcoholic
tx for severe hypophosphatemia
IV phosphorous (may need higher doses)
tx for moderate hypophosphatemia
oral phosphorous 1.5-2.0grams per day in 3-4 divided doses
how often should you monitor serum phosphorous once you start therapy
every 6 hours during first 48-72 hours
