Mod 4 Flashcards
Inotropic
An agent that increase the force of muscular contracture.
Dromotropic
Affecting the conductivity of nerve or muscle fibers
Chronotropic
Influencing the rate of occurrence of an event such as the heart beat.
Cardiac output
the amount of blood pumped from the heart in 1 minute. (S/V x H/R= CO)
Stroke volume
the amount of blood ejected by the left ventricle (oxygenated blood) with each contraction.
Preload
is volume of unoxygenated blood coming into the heart (rt atrium). Increased in hypervolemia and regurgitation of valves
Afterload
is the resistance in the arterial system against which the left ventricle must contract to get oxygenated blood out the body. It is increased in hypertension and vasoconstriction.
BNP Lab-b-type natriuretic peptide
elevated BNP levels are noted in heart failure. It is used to diagnose heart failure and grade the severity of heart failure
Cardiac Glycosides originate for what plant?
foxglove plant
How are Cardiac Glycosides given?
because of their long half life it take them days to reach therapeutic blood levels. So a loading or digitalizing dose is given, followed by maintenance doses.
How do Cardiac Glycosides work?
They make increased intracellular calcium available to the myocardium, thus an enhanced force of contraction. They stimulate the parasympathetic nervous system, increasing vagal tone and slowing the heart rate
- Positive Inotropic- increase the force of the cardiac contraction
- Negative dromotropic- slow or delays conduction of the heart.
- Negative chronotropic- deceleration of the rate of the heartbeat
If Cardiac Glycosides are re administered they are eliminated after how many half lives?
5 half lives
what are Cardiac Glycosides used to TX?
CHF, atrial fibrillation / flutter and paroxysmal atrial tachycardia. (PAT)
Digoxin ( Lanoxin, Lanoxicaps)
- commonly used; PO or IV
- not used IM - severe pain at site with increased CPK – complicating interpretation of enzyme levels. –Therapeutic serum concentration 0.5-2ng/ml.
- half life is 1.6 days, can’t wait 8 days to reach a steady state for life threatening arrthymias
what is the antidote for digoxin?
digibind- but because of high cost it is used only in life threatening situations. Hold dig, hydrate to flush out of body.
Digitoxin (Crystodigin)
used rarely because of long half life with prolongs duration of adverse effects; PO, therapeutic range is 14-26 ng/ml
what are the adverse effects of Cardiac Glycosides?
- they have a narrow therapeutic range and may produce digitalis toxicity.
- These conditions may predispose a client; hypokalemia
what are early S/S of digitalis toxicity?
visual changes (blue green vision), difficulty reading, GI complaints –N/V, anorexia, diarrhea, bradycardia, headache, malaise, confusion
what drug has a synergistic effect with digoxin?
Quinidine: will cause increased glycoside serum level
what are Bipyridine used to TX?
It is used for short term management of CHF in clients who haven’t responded well to digitalis, positive inotropic effects
Primacor
IV only, pos inotropic and vasodilator, decreases preload and afterload, increases myocardial contractility, increases CO and diastolic function, short term tx for CHF, ordered mcq/kg of body wt
nesiritide (Natrecor)
- formulation of BNP ( b-type natriuretic peptide)
- Elevated BNP levels are noted in HF
- Effects are to reduce preload and afterload which are beneficial in HF
what must the nurse do before giving a cardiac glycoside?
Take apical pulse before administering each cardiac glycoside dose: do not administer if pulse is less than 60.(not radial pulse).
when giving digoxin you will never give it how?
IM
What will the nurse need to monitor while giving a cardiac glycoside?
- -monitor dig levels- draw blood at least 8 hours after last oral dose and preferably immediately before administering daily maintenance dose.
- Monitor client’s blood urea nitrogen (BUN), potassium and creatinine.
- Measure client’s fluid intake and output and weight.
what dose the nurse want to teach a patient taking cardiac glycoside?
- Teach client to take pulse.
- Ensure that client is familiar with symptoms that should be reported immediately, especially sudden weight gain, edema, shortness of breath, nausea and vomiting, and visual disturbances.
- Advise client to prevent deterioration of inotropic agents by always storing medication in a tightly fitting, light- and moisture- resistant container.
- Instruct client to check with physician before taking any nonprescription drug, such as an antacid.
- Do not give Lanoxin with high fiber meals.
Dopamine
- Part of the sympathomimetics system, is -used to: treat shock, & CHF to increase CO.
- It is given IV.
- When administering monitor v/s at least q 15-30 min, especially bp & pulse.
- Systolic should be greater than 90.
- There should be an increase in urine output (assess hourly).
- It improves perfusion to vital organs. It is a vasodilation.
- -Monitor for extravasation & peripheral pulses 2-4 hour.
- Titrate off & monitor for decreased b/p.
- Never use a gravity drip & always used a dedicated line.
what is Antiarrhythmic agents (Antidysrhythmics) used to TX?
Used to treat abnormal electrical activity in the heart by limiting cardiac electrical activity to normal conduction pathways and decreasing abnormally rapid heart rates.
