EKG and electrolytes Flashcards
Potassium action
- K+ and NA+ pump intracellularly / extracellularly
- Determines conduction velocity
- Helps to confine pacing activity to the SA node
- Excess or deficiency can alter myocardial muscle function
hyperkalemia EKG changes
(1) Tall, peaked T-waves
(2) Prolonged PRI, loss of P waves, ST segment depression, widening QRS complex
(3) Dysrhythmias – heart block, ventricular fibrillation, cardiac standstill
hyperkalemia mechanism
(1) Decreases rate of ventricular depolarization (slows)
(2) Shortens repolarization (accelerates)
(3) Depresses AV conduction
hyperkalemia causes
(1) Impaired renal excretion
(2) Excess K+ administration
(3) K+ sparing diuretics (spiralactone), ACE inhibitors, ARB drugs
(4) Extensive skeletal muscle destruction
***(K+ leave cells bc muscle crushed, burned patient expects increase bc it releases K+ since cells destroyed and leak out of blood vessels; burn and crushed injuries leads to this)
overall: either consume too much, kidneys don’t work, or drug is sparing too much K)
hyperkalemia management
(1) Stop oral and IV intake of K+
(2) Increase K+ excretion
(3) Force K+ from ECF to ICF (insulin, bicarb, albuterol)
(4) Stabilize cardiac cell membrane
(DICK)
hypokalemia EKG changes
(1) Flattened T wave, depresses ST segment, p waves peak, QRS prolonged, U wave
(2) Risk for heart block, ventricular tachycardia, ventricular fibrillation
hypokalemia mechanisms
- impaires myocardial conduction
- prolongs ventricular replolarization
hypokalemia causes
(1) Increased loss of K+ (loop sparing diuretics, increase renal loss, diarrhea)
(2) Increased shift of K+ from ECF to ICF
(3) Dietary K+ deficiency
(4) Renal losses
hypokalemia management
Oral or IV K+ replacement
(a) High Alert Medication
(b) NEVER IV push, (Give 10 mEq/hour- infusion pump)
(c) Dilute K+ sufficiently & administer slowly
(d) Monitor for phlebitis
magnesium actions
- Essential for enzyme, protein, lipid, and carbohydrate functions in the body
- Extracellular level essential for normal cardiac muscle function
hypermagnesemia (RARE) EKG changes
like hyperkalemia
(1) Tall, peaked T-waves
(2) Prolonged PRI, loss of P waves, ST segment depression, widening QRS complex
(3) Dysrhythmias – heart block, ventricular fibrillation, cardiac standstill
if all electrolytes are abnormally low what do you replace first and why
magnesium since it will overpower K+ and deplete everything. so Mg first, K+ second, and Ca third
hypermagnesemia causes
increased intake
excess IV magnesium administration
hypomagnesemia EKG changes
(1) Prolonged ST segment, Prolonged QT interval
(2) Torsades de pointes, ventricular fibrillation
hypomagnesemia mechanism
(1) Impairs myocardial conduction
(2) Prolongs ventricular repolarization
(3) May lead to coronary artery spasm, hypertension
hypomagnesemia causes
(1) Prolonged fasting or starvation
(2) Chronic alcoholism
(3) Fluid loss from GI tract
(4) Diuresis/proton pump inhibitors
(5) Hyperglycemic osmotic diuresis
hypomagnesemia management
(1) Treat underlying cause
(2) Magnesium replacement
(a) Mild symptoms – oral replacement and increase dietary intake Mg++
(b) If deficiency severe or if hypocalcemia present, IV Mg++ given
calcium actions
- Mediator for cardiac functions with effect on:
a) Vascular tone
b) Myocardial contractility
c) Cardiac excitability
when replaced Ca also replace vitamin D
hypercalcemia EKG changes
(1) Shortened ST segment, shortened QT interval
(2) Ventricular dysrhythmias
hypercalcemia causes
(1) Cancer
(2) Hyperparathyroidism
(3) Endocrine disorders
(4) Overdose vitamin A or D
hypercalcemia management
(1) Low calcium diet
(2) Increased weight bearing activity
(3) Increased fluid intake
(4) Hydration with isotonic saline infusion
(5) Bisphosphonates
(6) Calcitonin SQ or IM
hypocalcemia ekg changes
(1) Prolonged ST segment, Prolonged QT interval
(2) V-tachycardia
hypocalcemia mechanisms
(1) Decreases myocardial contractility
(2) Reduces cardiac output
(3) Hypotension
(4) Decreases responsiveness to Digitalis
if too low can causes seizures and dysrhythmias
hypocalcemia causes
(1) Decreased production of parathyroid hormone
(2) Multiple blood transfusions
(3) Alkalosis
(4) Increased calcium loss
(5) Low magnesium levels
hypocalcemia management
(1) Treat cause
(2) Calcium and Vitamin D supplements
(3) IV Calcium gluconate
(4) Seizure precautions
