Intro to the Cardiovascular System

CHAPTER 28

Intro to Cardiovascular System

Heart’s ability to pump blood is the result of 5 qualities unique to heart tissue

5 Qualities to Cardiac Tissue

Automaticity--ability to initiate its own electrical stimulus

Excitability-ability to respond to electrical stimulation

Conductivity-ability to transmit electrical stimulus from cell to cell within the heart

5 Qualities to Cardiac Tissue

Contractility-ability to stretch as a single unit and recoil

Rhythmicity-ability to repeat the cycle with regularity

Anatomy & Physiology

Make sure you review on your own!!!!

Cardiac Output Pg. 425

Amount of blood pumped out of left ventricle each minute.

Cardiac output ranges from 4 to 8 L/min (average about 5) Varies according to body size. Heart adjusts amt. To need.

Can be increased by increasing heart rate and by increasing stroke volume (amt per beat)

Stroke volume avg 65 to 70ml

NURSING GUIDELINES 28-1

Assessing BP and Pulse for Postural Changes!!!

Factors that Alter Heart Rate & Rhythm

BOX 28-1 PG 425

History (Hx) Pg. 426

Description of symptoms past medical hx of angina, MI and any cardiac

surgeries prescription and nonprescription drugs drug and food allergy (iodine & seafood)

General Appearance

Nonverbal behavior and body position may indicate that the client is anxious, depressed, in pain, or uncomfortable

Pain

Poor circulation causes ischemia (reduced blood supply).

Classic sign of ischemia is pain caused by lack of oxygen

Chest pain Leg pain –- with exercise can indicate

inadequate oxygenation to leg muscles.

Assessing Cardiac Pain

Description of pain ( sharp,dull, squeezing, crushing)

Location and any radiation Duration of pain. When did it start and end? Radiation of pain to other areas Change in character Intensity -use 1 to 10 scale Relation of onset-eating, exercise, emotion

Temperature

Fever is characteristic of some heart disease. Inflammatory Response r/t damaged myocardial cells or to infection such as rheumatic fever and endocarditis.

Most agencies do not allow rectal temp. as stimulates vagus nerve and causes bradycardia.

Pulse Rate

Note rate, rhythm and quality (volume) Volume feels full, weak or thready determine pulse deficit--two nurses, one watch,

taken a full minute at the same time. One checks radial and other nurse counts apical

Blood Pressure

Take sitting, lying and standing if not acute (orthostatic BP)

Take in both arms on admission & report differences

Question about dizziness or light- headedness when changing position—may be r/t orthostatic hypotension (postural)

Cardiac Monitor

Reveals heart’s electrical activity but not mechanical

Telemetry used for continuous monitoring. Battery pack used is secured inside gown and read in station. EMS personnel can communicate info back to hosp with equip

Normal heart sounds

1st heart sound (lub) is the closing of mitral and tricuspid valves--S1. Heard loudest over apex and nearly simultaneous with palpated pulse

2nd heart sound (dub) is closing of aortic and pulmonic valves--S2. Heard loudest at 2nd intercostal space to right of sternum

Abnormal Heart Sounds

All other sounds are abnormal May also have murmurs and clicks caused by

turbulent blood flow through diseased heart valves.

A rough, rating sound may be caused by a friction rub, which is indicative or pericarditis (inflammation of the pericardium)

Skin assessment

Good light needed to assess Assess Cyanosis in oral mucous membranes,

lips, earlobes and nail beds In dark skinned a grayish cast is pallor Warm, cold, dry or clammy Check temp of feet & legs and for varicosities.

Sparse hair growth on legs & thick toenails indicate poor circulation.

Peripheral Edema

Edema occurs when blood is not pumped efficiently or when plasma protein levels are inadequate to maintain osmotic pressure.

When heart failure occurs fluid goes to dependent areas--feet, ankles, sacrum, fingers, hands

Peripheral Edema

Check for pitting edema To assess for edema, the examiner’s fingers

are gently pressed into the skin and then quickly released. If the marks of the fingers remain, the effect is termed pitting edema.

Edema is evaluated on a scale of +1 to +5. Refer to skills book.

Pitting Edema + 2

Weight

2 lb weight gain in short period indicates 1 additional liter of fluid

Pt weighed at the same time, with the same amount of clothing, using the same scale, each day.

Lung Sounds

If the left side of the heart fails to pump efficiently, blood backs up into the pulmonary veins and lung tissues.

Left sided CHF a crackling sound is heard. Wheezes and gurgles may also be heard

If uncorrected leads to Rt sided failure because the circulatory system is a continuous loop.

Sputum

Clients with cardiac disease may have a productive cough or non-productive cough

Note the type and frequency of the cough and the amount and appearance of the sputum.

It can be important in diagnosing heart failure or other pulmonary complications.

Mental Status

Assess for confusion or disorientation caused by cerebral ischemia

Extremes of emotion or alteration of thought processes is reported

Lab Tests

CBC, FBS, electrolytes, cholesterol and triglyceride levels may be done as part of the diagnostic analysis.

Serum Enzymes and Isoenzymes

Enzymes are complex proteins produced by living cells that function as catalysts.

Catalysts are substances that are capable of producing chemical changes without being changed themselves.

An isoenzyme is one of several forms of the same enzyme that may exist in cells and is capable of being identified separately from others.

Serum Enzymes and Isoenzymes

When tissues and cells break down, are damaged, or die, great quantities of certain enzymes are released into the bloodstream.

Serum Enzymes and Isoenzymes

The following are important in cardiac disease– Troponin, an enzyme in myocardial contractile

tissue. – Creatine kinase (CK), formerly creatine– Lactate dehydrogenase (LDH) and its isoenzymes – Aspartate aminotransferase (AST), formerly serum

glutamic-oxaloacetic transaminase

Serum Enzymes and Isoenzymes

Troponin is present only in myocardial tissue

Therefore, it is specific for determining heart damage in the early stage of an MI.

The other enzymes can be elevated in response to cardiac or other organ damage.

Electron Beam Computed Tomography

EBCT is a radiologic test that produces x-rays of the coronary arteries using an electron beam

This noninvasive test can scan the heart in 1/20 of a second using 10 times less exposure to radiation than that of mechanical computed tomography (CT) machines.

Electron Beam Computed Tomography

The advantage of EBCT is that it can detect and quantify calcified plaque in the coronary arteries before clients who do not fit the usual cardiac risk profile are symptomatic.

Echocardiography

Echocardiography uses ultrasound waves to determine the functioning of the left ventricle and to detect cardiac tumors, congenital defects, and changes in the tissue layers of the heart.

Transesophageal echocardiography (TEE)

A second ultrasound technique is TEE, which, as the name implies, involves passing a tube with a small transducer internally from the mouth to the esophagus. (Fig. 28-11) pg 430.

When the transducer is located in the esophagus, which lies behind the heart, images of the posterior heart and its internal structures are obtained.

Electrocardiography Pg 430

The graphic recording of the electrical currents generated by the heart muscle.

Especially helpful in identifying cardiac arrhythmias and detecting myocardial damage.

12 lead

Ambulatory ECG

Holter monitor-wear 24 to 48 hours--keep diary of activity and symptoms.

Returned to MD to analyze the strips and correlate with incidences.

Exercise-Induced Stress Testing

Done to evaluate how the heart functions during exercise.

The electrical activity of the heart is assessed with an ECG monitor while the client walks on a treadmill, pedals a stationary bicycle, or climbs up and down stairs.

Exercise-Induced Stress Testing

The test is aborted if the client develops chest pain, severe dyspnea, elevated BP, confusion or dysrhythmias.

The physician monitors the ECG continuously throughout the test.

Drug-Induced Stress Testing

Drugs may be used to stress the heart for clients with sedentary lifestyles or those with a physical disability, such as severe arthritis, that interferes with exercise.

Adenocard, Persantine, or Dobutrex, may be administered IV.

Drug-Induced Stress Testing

Then Thallium, a radionuclide, is injected a few minutes later, a scan of the heart can detect compromised blood flow, which indicates coronary artery disease, or evidence of well-perfused heart muscle.

Cardiac Catheterization

A long flexible catheter is inserted from a peripheral blood vessel in the groin, arm, or neck into one of the great vessels and then into the heart.

Can be carried out on the left side of the heart by way of an artery or on the right side by way of a vein.

Cardiac Catheterization

Usual length of stay is at least 5 to 9 hours or overnight.

Which meds needs to be omitted the day of—asks md.

Food and fluids are usually held, unless scheduled late in the day.

Cardiac Catheterization

Pt is asked again about allergies because a reaction could be life-threatening. Especially to iodine, shell fish, radiographic dye, and latex.

IV fluids administered Sedative give, but anesthesia is not necessary.

Cardiac Catheterization

The skin over the catheter insertion site is cleansed with an antiseptic.

The presence and quality of peripheral pulses and skin color and temperature are documented before the start of the procedure.

Cardiac Catheterization

Client feels a brief warm sensation as the dye is administered.

Pt. Must report chest discomfort, nausea, or difficulty breathing.

After Cardiac Catheterization

Keep the extremity straight for several hours and avoid movement are important.

BP and pulse are monitored frequently Dressing checked frequently for bleeding. The pulse is palpated in various locations and

the color and temperature in the extremity are checked to confirm that blood is circulating well.

After Cardiac Catheterization

Report any warm, wet feeling that may indicate oozing blood, numbness, tingling, or sharp pain in the extremity.

Drink a large volume of fluid to relieve thirst and promote the excretion of the dye

Follow Discharge Instruction Box 28-2 pg. 432

Electrophysiology Studies pg. 432

An electrophysiology study is a procedure that enables the physician to examine the electrical activity of the heart, produce actual dysrhythmias by stimulating structures in the conduction pathway, determine the best method for preventing further dysrhythmic episodes, and, in some cases, eradicate the precise location in the heart that is producing the dysrhythmia.

Electrophysiology Studies

Once the dysrhythmia is produced, the physician uses several drugs to evaluate each one’s efficacy at restoring normal heart rhythm.

The outcome of the trial drugs helps determine how to relieve the client’s symptoms medically.

The normal heart rhythm also may be restored with electrical shocks.

NOT ON THE TEST!!!

Hemodynamic monitoring pg.433

Nursing Process pg 435 & 436

On your own!!

Auscultation Web-Sites

http://www.med.ucla.edu/wilkes/intro.html

http://members.aol.com/kjbleu/heartsounds.html

http://www.bioscience.org/atlases/heart/