Manage UsersNCLEX Study Guide

Article

Cardiovascular system

04/29/2011

Katrina
Member since: April 2011
(Boynton Beach,FL)

What is the relationship of the kidneys to the cardiovascular system?

  • The kidneys filter about 1 L of blood per minute.
  • If cardiac output is decreased, the amt of blood going thru the kidneys id decreased; urinary output is decreased.  Therefore, a decreased urinary output may be a sign of cardiac problems.
  • When the kidneys produce and excrete 0.5 ml of urine/kg of body weight or average 30 ml/hr output, the blood supply is considered to be minimally adequate to perfuse the vital organs.

Angina

Chest discomfort or pain that occurs when the myocardial oxygen demands exceed supply and is relieved by rest.
ECG: ST depression and T wave inversion.

During an attack:

  • Immediate rest
  • Administer no more than 3 nitro tablets, 5 min apart

Teach that sexual activity may be resumed after exercise is tolerated, usually when able to climb 2 flights of stairs without exertion.  Nitro can be taken prophylactically before intercourse.
Which meds would be appropriate for acute angina?

  • Digoxin – not appropriate bc increase the strength and contractility of the heart muscle; the problem in angina is that the muscle is not receiving enough oxygen.  Dig will not help
  • Atropine – not appropriate; increases heart rate by blocking vagal stimulation; does not address the lack of O2 to the heart muscle.
  • Propranolol (inderal) – not appropriate for acute angina attack; however, is appropriate for long-term management of stable angina because it acts as a beta blocker to control vasoconstriction.

Myocardial Infarction

Disruption in or deficiency of coronary artery blood supply, resulting in necrosis of myocardial tissue.

  • Pain not relieved by rest
  • Pain not relieved by nitroglycerin
  • Pain may persist for hours or days.
  • Cardiac dysrhythmias
  • Narrowed pulse pressure

For pain and to increase O2 perfusion, IV morphine sulfate (acts as a peripheral vasodilator and decreases venous return).  Bed rest for 24 hours.

Hypertension

BP equal to or greater than 140/90 on two separate occasions.
BP is created by the difference in the pressure of the blood as it leaves the heart and the resistance it meets flowing out to the tissues.  Any factor that alters cardiac output or peripheral vascular resistance will alter BP.
Risk factors for HTN:  heredity, race, age, alcohol abuse, increased salt intake, obesity, and use of oral contraceptives.
The number one cause of a CVA in hypertensive clients is noncompliance with medication regime.  HTN is often symptomless, and antiHTN meds are expensive and have SE. Teaching is important.
Peripheral Vascular Disease (PVD)
Arterial:

  • Reynaud disease – nonatherosclerotic, triggered by extreme heat or cold.
  • Buerger disease – occlusive inflammatory disease, strongly associated with smoking.
  • Smooth skin, shiny skin, loss of hair, thickened nails
  • Pain
    • Sharp, increases with walking and elevation
    • Intermittent claudication: classic presenting symptom; occurs in skeletal muscles during exercise; is relieved by rest.
    • Rest pain – occurs when extremities are horizontal; may be relieved by dependent position

Venous:

  • Varicose veins
  • Thrombophlebitis
  • Venous stasis ulcers
  • Brown pigment around ankles
  • Pain
    • Aching, dull
    • Relieved when horizontal, use SCDs

Decreased blood flow results in diminished sensation in the lower extremities.  Any heat source can cause severe burns before the client realizes the damage is being done.

AAA

A client is admitted with severe chest pain and states that he feels a terrible tearing sensation in his chest.  He is diagnosed with a dissecting aortic aneurysm.  What assessments should the nurse obtain in the first few hours?

  • VS q hr
  • Neurologic vital signs
  • Respiratory status
  • Urinary output
  • Peripheral pulses

During aortic aneurysm repair, the large arteries are clamped for a period of time, and kidney damage can result.  Monitor daily BUN and creatinine levels.  Normal BUN is 10-20 mg/dl and normal creatinine is 0.2-1-2 mg/dl.  The ratio of BUN to creatinine is 20:1.  When this ration increases or decreases, suspect renal problems.

Thrombophlebitis

a positive Homan’s sign is considered early indication of thrombophlebitis.  However, it may also indicate muscle inflammation.  If a DVT has been confirmed, don’t do Homan’s.
Heparin prevents conversion of fibrinogen to fibrin and prothombin to thrombin, inhibiting clot formation.  Do not massage area or aspirate; give in the abdomen between the pelvic bones, 2 inches from the umbilicus.
Heparin

  • Antagonist – protamine sulfate
  • Lab:  PTT or APTT
  • Keep 1.5-2.5 time normal control

Coumadin

  • Antagonist – vit K
  • Lab: PT
  • Keep 1.5-2.5 time normal
  • INR desirable therapeutic level usually 2-3 sec

Dysrhythmias

A holter monitor offers continuous observation of client’s heart rate.  Teach client to keep a record of: medication times and doses, chest pain episodes: type and duration, valsalva maneuver (straining at stool, sneezing, coughing), sexual activity, and exercise.
Cardioversion is the delivery of synchronized electrical shocks to the myocardium.
Determine serum electrolyte levels, esp. K and Mg (alcoholics)
Difference in synchronous and asynchronous pacemakers:

  • Synchronous, or demand, pacemakers fires only when the client’s heart rate falls below a rate set on the generator.
  • Asynchronous, or fixed, pacemaker fires at a constant rate.

Heart failure

Restricting sodium reduces salt and water retention, thereby reducing vascular volume and preload
Digitalis

  • SE are increased when pt is hypokalemic
  • Digitalis has a negative chronotropic effect – it slows the heart rate.  Hold if pulse rate is <60 or >120 or has markedly changed rhythm.
  • Bradycardia, tachycardia, and dysrhythmias may be signs of toxicity; these signs include NV and headache
  • If withheld, call MD

Inflammatory and infectious heart disease

Infective endocarditis damage to heart valves occurs with the growth of vegetative lesions on valve leaflets.  These lesions pose a risk for embolization; erosion or perforation of the valve leaflets; or abscesses within adjacent myocardial tissue.  Valvular stenosis or regurgitation (insufficiency), most commonly of the mitral valve, can occur, depending upon the type of damage inflicted by the lesions, and can lead to symptoms of left- or right-sided heart failure.
There are two types of infective endocarditis:  acute, which often affects individuals with previously normal hearts and healthy valves and carries a high mortality rate; and subacute, which typically affects individual with preexisting conditions, such as rheumatic heart disease, mitral valve prolapse, or immunosuppression.  IV drug users are at risk for both.  When this population develops subacute infective endocarditis, the valves on the r side of the heart (tricuspid and pulmonic) are typically affected because of the introduction of common pathogens that colonize the skin into the venous system.
The presence of a friction rub is an indication of percarditis (inflammation of the lining of the heart).   ST segment elevation and T wave inversion are also signs of pericarditis.

Valvular heart disease

In mitral valve stenosis, blood is regurgitated back into the left atrium from the left ventricle.  In the early period, there may be no symptoms: but as the disease progresses, the client will exhibit excessive fatigue, dyspnea on exertion, orthopnea, dry cough, hemoptysis, or pulmonary edema.  There will be a rumbling apical diastolic murmur, and atrial fibrillation is common.
Common causes:

  • Syphilis
  • Rheumatic fever
  • Endocarditis