N341 EXAM 3, part 2: Potassium/Calcium

Hydrogen

acid

moves into cell if basic, and out of cell if acidic --> hydrogen moves in and out to neutralize the body.

Potassium normal level

3.5-5.0 mEq/L

Potassium function

- cation (+ charge) in ICF

- must be ingested daily, body does not conserve it

function --> MUSCLES

- neromuscular function

- transmission of nerve impulses

- muscle contraction

- cell electrical neutrality

potassium diet sources

- chocolate

- dry fruits, nuts, seeds

- fruits: oranges, bananas, apricots, cantaloupe

- meats

- vegetables: beans, potatoes, mushrooms, tomatoes, celery

IC v EC potassium

high in IC, low in EC

H+ is low (neutral) in both

how does K+ and H+ move in acidosis

K+ out

H+ in

--> to make more basic

how does K+ and H+ move in alkalosis

K+ in

H+ out

--> to make more acidic

how does the body regulate potassium?

ingesion --> NEED 40-60 mEq of K+ per day (b/c body cannot conserve)

renal regulation --> excreted through kidneys (can't conserve, but can excrete extra w/ aldosterone when needed)

pH level --> K+ and H+ exchage to maintain balance

sodium-potassium pump --> pulls potassium in and out of cells against concentration gradient and osmosis

Hypokalemia

<3.5 mEq/L --> not enough potassium

Hypokalemia etiology/cause

inadequate intake of potassium --> usually d/t TPN, NPO, or alcoholism

excessive output --> intestinal fluids have alot of potassium

- suction

- lavage (washing stuff out)

- prolonged vomitting

- diarrhea

- fistuals

- laxitive abuse

- prolonged diaphoresis (potassium wasting)

- diuresis from newly implanted kidney

- osmotic diuresis (high urine glucose level)

- elevated aldosterone production --> conserving sodium, wastes potassium

- alkalosis --> potassium moves into cell)

What drugs cause hypokalemia?

- loop + thiazide diuretics --> waste potassium

- corticosteroids --> body conserves salt, loses potassium

- insulin

- some antibiotics

- laxatives --> lose potassium through GI

Insulin affect on potassium

treats hyperkalemia --> moves potassium into our cells (stashes it)

so BAD for HYPOkalemia

hypokalemia clinical manifestations

WEAK AND SLOW

Cardiac

- EKG changes --> heart muscles not depolerize/repolerize

- disrhythmias --> not contracting normal

- PROMINENT U WAVE

- irregular weak pulse

- orthostatic hypotension

muscular

- skeletal musle weakness

- paralysis

- rhadbdomyolysis --> we don't use our muscles, they break down

smooth muscle weakness (GI)

- constipation

- paralytic ileus

- anorexia

- N/V

hypokalemia diagnostic test result

- serum potassium level <3.5

- elevated pH and Bicarb levels

- slightly elevated serum glucose level

- characteristic EKG changes --> SHALLOW T WAVE and PROMINENT U WAVE

with hypokalemia the U wave is...

bigger --> takes longer to charge

hypokalemia treatment

Oral replacement

- food high in potassium

- potassium supplement --> drink w/ FULL glass of water, do NOT crush extended release

IV potassium replacement --> dangerous, but commin (impacts heart, cardiac arrest is possible)

IV potassium replacement

- high alert med

- dilute in compatible solution

- dose should NOT EXCEED 40mEq/L

- rates should NOT EXCEED 10-20 mEq/hr

- NO BOLUS or DIRECTLY FROM VIAL

- check serum potassium levels frequently

- irritating to tissue --> more PROXIMAL and LARGER VESSEL

hypokalemia nursing interventions

- monitor VS/BP every 15 minutes

- safety d/t weakness

- EKG monitor for U wave

- I/O --> diuretic may be contributing

- check for alkalosis --> ABG

- admin appropriate replacemnt therapy

hypokalemia and digoxin

MONITOR --> hypokalemia and digoxin can cause TOXICITY

hyperkalemia

> 5 mEq/L --> high potassium, less common, but DEADLY, cardiac arrest possible at any moment

hyperkalemia etiology/cause

increased intake of potassium --> not typical, but caused by SALT SUBSTITUTES

decreased potassium exretion

- renal failure

- low aldosterone --> not excreting potassium

injury --> when cell is injured, potassium is released (99% of potassium is in the cells)

- burns, infection, chemo, trauma

other causes

- acidosis --> pulls potassium out

- donate blood --> when nearing expiration, potassium rises (monitor K+ when giving blood products)

drugs that cause hyperkalemia

- beta blockers

- potassium sparing diuretics

- some anitibiotics

- ACE inhibitors --> suppress aldosterone

- NSAIDS --> suppress aldosterone

- chemo --> cells open/die

hyperkalemia diagnostics

- serum potassium level >5 mEq/L

- decreasd arterial pH --> K moves into cell and H moves out

- EKG abnormalities --> tall T wave

hyperkalemia clinical manifestations

effects heart, smooth muscle mostly

cardiac

- tall, peaked T wave

- ventricular arrhythmia and cardiac arrest

- slow HR

- slow BP

neuromuscular (slow, sluggish)

- muscle weakness

- paralysis

GI (hyperactivity of smooth muscle)

- Nausea and diarrhea

hyperkalemia EKG changes

hyperkalemia treatment

life threatening --> detect/treat EARLY

restrict potassium intake --> limit oral and IV intake

promote potassium excretion

- diurectics

- kayexalate

- increased fluid intake (IF kidneys work)

- dialysis --> common

move potassium in cell

- insulin w/ glucose --> hides potassium until treatment is figured out

- treat acidosis w/ bicarb

protect the heart

- administer calcium gluconate

what does kayexalate do w/ hyperkalemia

causes p/t to poop out potassium

calcium gluconate use w/ hyperkalemia

cardiac protectant (calcium chill/relaxes heart + muscles) while you work to get potassium down

HIGH ALERT med

hyperkalemia nursing interventions

- monitor cardiac status w/ EKG

- monitor I/O's --> not excreting urine? likely the cause

- prepare to administer calcium gluconate

- prepare dialysis if no response to treatment (long-term fix)

Calcium level

8.6-11 mg/dL

calcium function

skeletal and heart muscle contraction.

- CALMS nerve cells (chills everything out)

- nerve impulse and transmission

- blood clotting

- building bones and teeth (99% stored there)

parathyroid hormone effects on calcium

promotes calcium resorption from the bones and teeth

- causes serum calcium to rise

- steals calcium from bones/teeth

- tell kidneys to conserve Ca and GI to absorb Ca

calcitonin effect on calcium

antagonizes parathyroid hormone --> when Ca is too high, tells it to stop

pH impacts on calcium

INVERSE relationship

High pH = Low Calcium

high pH (alkalosis) causes calcium to bind to albumin, lowering total available ionized calcium

phosphates relationship with calcium

INVERSE

- Ca binds to phophate

- high phosphate levels --> low Ca d/t binding

RENAL FAILURE causes high phosphate levels leading to hypocalcemia

magnesium and calcium

HYPOmagnesemia causes end organ reistence to PTH and decreaeed production of PTH reulting in HYPOcalcemia

calcium foods

- dariy

- leafy green vegetables

- whole grains

- tuna and salmon

- vit D

why is vitamin D important to calcium?

vit D is needed to absorb Ca in the GI tract.

vit D deficient = hypocalcemia

hypocalcemia level

< 8.6 mg/dL

hypocalcemia etiology/cause

- hypoparathyroidism --> decreased levels of PTH, take calcium from bones/teeth

- hypoalbuminemia --> not as much Ca bound to albumin

- pancreaititis --> binds to fat

- magnesium imbalance

- hyperphosphatemia

- alkolosis

- malabsorption syndromes (cannot absorb) --> diarrhea, laxative use, low vit D, Crohn's

- intake issues --> alcoholics and breast-fed babies

- citrate in blood porducts

burns/sepsis --> tissue traps Ca

hypocalcemia drug causes

- anticonvulsants (phenobarbital and phenytoin) --> interfere w/ vit D metabolism

- loop diuretics (lasix) --> waste calcium

- calcitonin --> parathyoid hormone antagonist

- antibiotics

- phosphates --> low calcium, enema

hypocalcemia clinical manifestations

Neuromuscular

- tetany

- Chvostek's sign

- Trousseau's sign

- hyperactive deep tendon reflexes

- laryngospasm --> airway may not close, have airway cart around

- seizures

GI

- hyperactive bowel sounds

- abdominal cramps

CNS

- irritability

- confusion

- delusions

- convulsions

- anxiety

cardiac --> cannot push a ton of blood out d/t partial contractions

- hypotension

- cardiac arrest

- decreased myocardial contractility

- prolonged QT interval and risk for torsades de points (fatal arrhythmia)

renal

- oliguria --> low urine output

- anuria --> no urine output

tetany

involentary contractions of muscles

Chvostek's sign

tap over facial nerve

- see contraction of upper lip, nose, cheek

Facial muscle spasm upon tapping

Trousseau's sign

inflate BP cuff 20 mmHg above systolic.

- see flexed wrist, adducted thumb, extended fingers (hand/risk contract)

arm/carpal spasm

hypocalcemia diagnostic results

- total serum calcium below 8.6 mg/dL

- ionized calcium below 4.5 mg/dL

characteristic EKG changes

hypocalcemia treatment

acute hypocalcemia (symptomatic --> medical emergency)

- administer calcium gluconate or calcium chloride

chronic hypocalcemia

- vid D supplement and calcium-rich diet

- phosphate binder (lower phosphate level)

calcium gluconate

- high alert medication

- do not give IM --> muscle necrosis

- dilute IV calcium in dextrose 5% and water

- do not push IV calcium --> bradycardia, hypotension, and cardiac arrest (heart too chill)

- VESICANT

hypocalcemia nursing interventions

- airway cart, trach tray, ambu bag

- cardiac monitor --> EKG changes

- seizure precaustions (pads, suction, etc.)

- avoid overstimulation (quiet room, limit visitors, soft lighting)

hypercalcemia level

>11 mg/dL

hypercalcemia etiology cause

hyperparathyroidism --> producing PTH at high level, losts of Ca being pulled out of bone

- cancer --> tumors secrete PTH

- multiple fractures --> Ca leaks out

- immobilization --> Ca leaks out

- hypophosphatemia (not enough, too many free Ca)

- acidosis --> pH low, Ca high

hypercalcemia drug causes

- thiazide diuretics --> potentiate PTH

- antacids --> lots of Ca

- lithium --> compete w/ Ca

- Vit A and D --> absorb too much Ca

hypercalcemia clinical manifestations

(decreased neuromuscular irratibility)

Cardiac

- HTN

- dysrhythmia --> heart block (HR slow, forgets to beat) and cardiac arrest

neuromuscular

- decreased deep tendon reflex

CNS

- bizzare behavior

- coma

- lethargy

GI

- hypoactive bowel sounds

- constipation

renal

- polyuria --> decreased renal function

- kidney stones --> made of calcium

skeletal

- bone fractures/pain

hypercalcemia diagnostic results

- serum Ca >11 mg/dL

- ionized Ca >5.5 mg/dL

- digitalis toxicity

- X-ray revealing pathologic fractures

- characteristic EKG changes

digitalis toxicity

toxic drug effects from administration of digoxin

hypercalcemia treatment

- limit intake and flush out --> dietary, meds, IV infusion

- hydrate the p/t --> oral 3,000-4,000 mL per day, IV 0.9% saline

- loop diuretic (NO thiazide diuretics)

- dialysis (life threatening hypercalcemia)

- corticosteroids --> block bone resportion and GI absorption of calcium

- calcitonin --> stop parathyroid hormone

- biphosphates

- weight bearing activity --> force calcium back into bones

hypercalcemia nursing interventions

- cardiac monitor for arrhythmias

- assess for kidney stones (strain urine)

- I/O --> renal failure common