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89 terms

electrolytes 2 (K and Ca)

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pH (acid/base balance of the body)
[K] is closely related to what?
kidneys
Potassium is mainly excreted how?
no (But [K] correlates to K disorders quite well)
Is [K] a good measure of TBK?
muscle weakness/cramps, nausea, vomiting, polyuria, EKG changes, cardiac arrhythmias, increased pH and bicarb levels
Signs and symptoms of hypokalemia
weakness/cramps
Hypokalemia causes muscle ____
increased (so does HYPER CAL cemia)
Hypokalemia causes ____ urine excretion
heart, cardiac arrhythmias (and EKG changes)
What organ does hypokalemia affect and how?
digoxin
Hypokalemia is associated with toxicity of what medication?
increase
Hypokalemia causes a ___ in pH
increase
Hypokalemia causes a ___ in bicarb levels
GI, renal (high aldosterone, low, Mg), inadequate intake of fluids, alkalosis, medications
What are the causes of hypokalemia?
diuretics, high dose antibiotics, corticosteroids, B2 agonists, insulin, aminoglycosides, amphotericin B, cisplatin, foscarnet
What medications cause K depletion?
K (potassium)
diuretics, high dose antibiotics, corticosteroids, B2 agonists, insulin, aminoglycosides, amphotericin B, cisplatin, foscarnet all cause depletion of what electrolyte?
B2 agonists and insulin
drug that causes hypokalemia through cellular redistribution
diuretics, high dose antibiotics, and corticosteroids
drugs that cause hypokalemia through renal potassium wasting
aminoglycosides, amphotericin B, cisplatin, foscarnet
drugs that cause hypokalemia secondary to Mg depletion
200 (mEq)
drop in [K] from 3 to 4 mEq/L indicates deficit of ____
200-400 (mEq)
drop in [K] from 3 to 2 mEq/L indicated deficit of ____
FALSE (use serum [K] and NOT a predetermined amount)
Potassium repletion should be guided by using a predetermined amount, rather than relying on serum [K]
KCl
What potassium salt should be used in hypokalemia/alkalosis?
anything but KCl (citrate, acetate, gluconate, or bicarbonate)
What potassium salt should be used in hypokalemia/acidosis?
KCl (except the effervescent tabs, which use KCl and Kbicarb)
What salt are oral K replacement products using?
acetate, Cl (usually saline solution; never concentrated potassium vials on patient units)
What salt are IV K replacement products using?
TRUE (oral route K sticks better)
Oral route is preferred mechanism of K replacement TRUE/FALSE
oral 40-120mEq daily
For moderate hypokalemia without EKG changes, what repletion strategy is indicated?
4-Kx100 (K range from 2.5-3.5, so 4-3 is 1, 100mEq per day)
Hypokalemia treatment rule of thumb
IV (replacement - usually 10-20mEq/hr of 40mEq/L conc. - max rate is 40, conc is 80)
For severe hypokalemia ( <2.5mEq/L) with or without EKG changes, what repletion strategy is indicated?
40 (mEq/hr - requires cardiac monitoring, when this fast)
What is the maximum infusion rate of potassium?
80 (mEq/L)
What is the maximum infusion concentration of potassium?
10 (mEq/hr)
What is the maximum K IV rate of infusion in a peripheral vein?
no (it augments K movement to ICF)
Can glucose be used for potassium infusion vehicle?
Mg
What electrolyte must be corrected along with K?
muscle weakness, parethesis(pins and needles), GI hypermotility, hypotension, EKG changes, decreased pH, increased potassium
What are the S/S of hyperkalemia?
hypermotility
How does kyperkalemia affect the GI tract?
peaked T-wave, shortened Q-T interval, widened QRS complex
How does hyperkalemia affect EKG?
cardiac arrhythmias, EKG changes
How does hyperkalemia affect the heart?
decreased pH
How does hyperkalemia affect pH?
increased intake, blood transfusions, rapid excessive IV administration, medications
What are the causes of hyperkalemia?
K supplements, K-sparing diuretics, ACE inhibitors, beta blockers, TMP/SMX, NSAIDs, digoxin, prograf, heparin, cyclosporin
What are medications that can cause hyperkalemia?
decreased excretion (renal failure, addison's disease - decreased ADH production), K release from cells (tissue breakdown - surgery, trauma, hemolysis and metabolic acidosis)
What are causes of hyperkalemia?
if [K] > 7
When is IV calcium indicated to oppose the effects of hyperkalemia?
oppose cardiac effects (IV Ca), promote K movement to ICF (using dex/insulin/bicarb)
What are 2 basic treatment strategies of hyperkalemia?
dextrose, insulin, bicarb (Acute) or beta agonists (non-acute, e.g., albuterol)
What solution can be used to promote the intracellular movement of potassium?
Kayexalate (sodium polystyrene sulfonate), loop diuretics, hemodialysis (only in CRF patients)
What drug can be used to remove potassium ions from the body?
Kayexalate, treats hyperkalemia (by removing K from the body)
What medication acts by exchanging Na for K in the gut and what is it used for?
CaCl2 injection (1mg or 13.5mEq - direct or diluted in D5W)
Treatment for hyperkalemia that works in 1-2mins and lasts only 30mins
yes (as often as needed)
Can CaCl2 injections be repeated to treat hyperkalemia?
50ml (25gm) IV over 5mins
How do you give dextrose 50% to treat hyperkalemia?
(give with) 20U insulin (over 1-2hrs .. starts working in 30mins and lasts 2-6 hours)
How do you give dextrose 10% to treat hyperkalemia?
15-60gm PO or PR
How should sodium polystyrene (KAYEXALATE) be given to treat hyperkalemia?
CaCl IV, dextrose50, dextrose10 with insulin, sodium polystyrene
What are 4 standard treatment strategies for hyperkalemia?
colonic necrosis and other GI effects (esp. when used with sorbitol)
Kayexalate is associated with what risks?
Vitamin D, calcitonin, PTH (parathyroid hormone)
[CA] and [phos] are regulated by a complex interaction between what 3 molecules?
bone
Where is 99/5% of the body's calcium found?
(enzyme) cofactor (in blood )clotting
What is the function of calcium?
it accounts for a decrease in percent of protein binding due to a decrease in serum albumin conc.
What is corrected calcium?
tetany, hypoactive (slow) reflex, CNS depression, hypotension, (trousseau's- hand and chvostek's - jaw signs)
What are the S/S of hypocalcemia?
hypoparathyroidism (low PTH), hypomagnesemia (causes low PTH secretion), hyperphosphatemia, chronic renal failure, vitamin D deficiency, acute pancreatitis, alkalosis, hypoalbuminemia, Mg depletion
What are the causes of hypocalcemia?
loop diuretics, corticosteroids, phenytoin, cisplatin, forcarnet, PO4 replacement products, pentamidine, alpha-interferon
What medications might cause hypocalcemia?
hypocalcemia
PIC TROUSSEA What does a positive sign indicate in this test?
hypocalcemia
PIC CHVOSTEK What does a positive sign indicate in this test?
calcium chloride
Which salt of calcium can only be given IV?
calcium acetate, carbonate, citrate
Which salt of calcium can only be given PO?
calcium gluconate
What salt of calcium can be given PO or IV?
gluconate (less irritating)
Preferred IV calcium product
chloride
This form of IV calcium can only be given through central line
carbonate (TUMS, OSCal and their generics)
Which PO salt of calcium gives more Ca per gram?
hypocalcemic symptoms present (paresthesia, tetany, Chvostek's sign), low serum [Ca], massive blood transfusion (esp with cardiac history), Ca chan blocker overdose, emergent hyperkalemia, receiving inotropic or vasopressor support
When is IV calcium appropriate?
magnesium
To effectively treat hypocalcemia, what body stores must be replete?
200-300mg elemental Ca IV (this means 1g of CaCl or 2-3g of Ca gluconate)
Treatment of acute symptomatic hypercalemia requires what?
30-60mg/min (ELEMENTAL CALCIUM - the salts will vary)
What is the maximum speed of elemental calcium?
oral calcium (supplementation of) 2-4g daily (of elemental calcium)
Treatment of chronic hypocalcemia requires what?
vitamin D
Many patients with chronic hypocalcemia must also receive _____
1gm CaCl or 2-3g CaGLU slow IV push
Suggested treatment for tetany (associated with hypocalcemia)
CNS depression, muscle weakness/pain, polyuria, kidney stone development, ECF depletion, heart failure, htn, constipation, increase digoxin toxicity
What are the signs and symptoms of hypercalcemia?
EKG (decreased QT interval), ventricular arrhythmias, htn, heart failure
Cardiac changes associated with hypercalcemia?
malignancy, hyperparathyroidism, thyrotoxicosis, TPN, immobilization, acidosis (decrease affinity of albumin for Ca - which causes more free calcium), milk, medications
What are the causes of hypercalcemia?
thiazide diuretics, estrogens and antiestrogens, lithium, vitamins A and D, calcium supplements
Which medications can cause hypercalcemia?
normal saline + furosemide (use only after ECF depletion is corrected, functioning kidneys necessary, monitoring K and Mg necessary)
Hypercalcemia treatment to enhance urinary calcium excretion
dialysis
Hypercalcemia treatment for patients with renal disease?
calcitonin, prostaglandin synthesis inhibitors, mithramycin, bisphosphonates, gallium, PTH antagonists
Hypercalcemia treatment to inhibit bone resorption
increases (serum calcium levels)
PTH hormone ____ calcium levels
PO/IV PO4
Hypercalemia treatment to increase calcium deposition
calcitonin (inhibits bone resorption)
What is a FAST treatment of hypercalcemia?
NS + furosemide or calcitonin (takes hours to correct)
Short term therapy for hypercalcemia
hydrocortisone or mithramycin (take days to correct)
Intermediate length therapy for hypercalcemia
zoledronic acid or pamidronate (takes weeks to correct)
Long term therapy for hypercalcemia
polyuria
Why are hypercalcemic patients usually dehydrated?
rehydrate with NS (monitoring for fluid overload), add furosemide (blocks Ca resorption), keep monitoring K and Mg
Steps to treat hypercalcemia