MEDICAL SURGICAL NURSING :INTRO TO THE CARDIOVASCULAR SYSTEM

MEDICAL SURGICAL NURSING

INTRO TO THE CARDIOVASCULAR SYSTEM

A & P OF THE HEART

QUALITIES UNIQUE TO CARDIAC TISSUE:

Automaticity – initiates own electrical stimulus

Excitability – responds to electrical stimulation

Conductivity – transmits electrical stimulus cell to cell

Contractility- stretches as a single unit & recoil

Rhythmicity – repeats the cycle regularly

HEART CHAMBERS & LAYERS – fig 28-1

Atria – upper chambers

Ventricles – lower chambers

Septum – wall between rt & lt sides

Base-upper portion

Apex-tip, lower portion

VALVES, ARTERIES & VEINS

VALVES – ensure that blood goes one way: forward

2 A-V valves separate atria & ventricles

2 semilunar valves between ventricles & pulmonary artery &
aorta

CIRCULATION - fig 28-3

Inferior/superior venae cava bring deoxygenated venous blood
from the body into the rt atrium

Blood pumped into the rt ventricle through the av / tricuspid
valve

BLOOD SUPPLY TO THE HEART

Blood goes from the rt ventricle through the pulmonic valve
into the pulmonary artery to the lungs to be oxygenated

Oxygenated blood is supplied to the heart muscle by left &
right coronary arteries

Heart muscle is lst to receive oxygenated blood –fig 28-4B

Left coronary arteries supply the blood to the left side which
is responsible for the pumping action of the heart

Right coronary arteries supply the blood to the right side
which is the conduction system

CARDIAC CYCLE

Contraction of the heart chambers – systole

Relaxation of the heart chambers– diastole

Atria contract at the same time

Ventricles contract at the same time

Lub dub sound – contraction of the atria & then the ventricles

Starling’s law-the greater the stretch of the myocardium the
stronger is the ventricular contraction- like the rubber band being
stretched.

CONDUCTION – fig 28-6

Electrical activity starts at the SA node- pacemaker of the
heart

AV node

Bundle of His

Bundle branches

Purkinje fibers

Polarization- cardiac cells in resting state

Depolarization – during spread of the electrical impulse

Refractory period – time when cells are resistant to electrical
stimulation

CONDUCTION

Depolarization & repolarization produce electrical changes in
the heart muscle

These changes can be detected by electrodes placed on the chest
wall & recorded by the electrocardiograph (EKG) machine

See fig 28-7

Regulation of Heart Rate

Autonomic nervous system

sympathetic – speeds up system

parasympathetic – slows down system

Baroreceptors

pressure sensitive

located in walls of atria & major blood vessels

Cardiac Output

Amount of blood pumped out of the left ventricle each minute

Normal in healthy adult: 4 – 8 L/min – varies with body size &
the body’s changing needs

Stroke volume – amount of blood pumped with each heart
contraction

Cardiac Output = heart rate x stroke volume

HISTORY

Present symptoms

Past medical hx of cardiac problems

Prescription & nonprescription drugs

Drug & food allergies – in case of allergy to seafood may also
be allergic to radiopaque dye used in diagnostic tests

If client in acute distress may have to get information from
family member

PHYSICAL EXAMINATION

General Appearance: nonverbal behavior &body position

Pain may be a sign of ischemia

V/S:

temperature – sign of inflammatory response

pulse - rate, rhythm & quality

respirations – rate, quality

BP – orthostatic, baseline, both arms & compare – nursing
guidelines 28-1

PHYSICAL EXAMINATION

Cardiac Rhythm – continuous cardiac monitoring, telemetry

Normal heart sounds-lub-dub

Abnormal heart sounds – extra sounds, friction rubs

Peripheral pulses – present or absent, equal on both sides,
quality

Skin – color, temperature, dry or clammy

PHYSICAL EXAMINATION

Peripheral edema – pitting or non – pitting, 1+ to 4+

Weight – recorded daily at the same time in same clothes on
same scale

Jugular Vein Distention– see fig 28-10

DIAGNOSTIC TESTING

Blood chemistry – FBS, electrolytes, cholesterol &
triglycerides

Serum enzymes & isoenzymes – specific to damage of heart
muscle:

troponin

creatine kinase (CK)

LDH

AST

DIAGNOSTIC TESTING

Electron Beam CT – xrays of the coronary
arteries

Radiography – xrays of the heart determine size & position of
the heart & condition of the lungs

MRI – used as a noninvasive method to identify structural
abnormalities; those with metallic implants, implanted pacemaker &/or
defibrillators are excluded

Echocardiography – sonogram of the heart to determine left
ventricular function, congenital defects & changes in the tissue layers of
the heart

DIAGNOSTIC TESTING

Electrocardiography or EKG/ECG – graphic recording of the
electrical activity of the heart. Should have a P wave, QRS complex

12 lead EKG done to diagnose cardiac problems, read by computer
& later by MD

CARDIAC CATHETERIZATION

Used to measure fluid pressures in the heart chambers & obtain
blood samples for analyzing O2 & CO2 levels

May be done to check left side of heart via artery or right
side of the heart via vein

Flexible catheter inserted into peripheral blood vessel in the
groin, arm or neck & threaded up into the heart

Dye instilled; client may feel warm sensation

Afterwards site covered with a pressure dressing

See box 28-2 for discharge teaching

　

ARTERIOGRAPHY

Coronary – most commonly used along with left sided cardiac
cath to determine degree of blockage in coronary arteries; dye instilled
into the artery

Angiocardiography – radiopaque dye injected into a vein.
Usually used to diagnose congenital abnormalities of the heart & great
vessels

Peripheral arteriography – used to diagnose occlusive disease
in the smaller arteries

Hemodynamic Monitoring

Used to assess the volume & pressure of blood in the heart &
vascular system

Methods

direct BP-cath placed in peripheral artery

central venous pressure (CVP)-rt atrial pressure – cath
inserted into large vein – fig 28-15

GENERAL NUTRITIONAL CONSIDERATIONS

Food & fluids are withheld before invasive
diagnostic procedures & are not resumed until the client is stable & free of
n/v

GENERAL PHARMACOLOGIC CONSIDERATIONS

All medications to include herbal or OTC can affect pulse rate
& BP. Be sure that all of them are listed in the pt’s history

Instruct a pt who is going to have a contrast medium injected
during a cardiac cath or arteriogram that they may feel an intense flushed
feeling & the urge to void when it is injected. The feelings should pass
within 30-60 secs

GENERAL GERONTOLOGIC CONSIDERATIONS

The aging heart is less able to meet the demands placed on it
during times of stress & requires more time to return to baseline levels

Older adults with renal impairment or chronic dehydration is at
increased risk of complications during & after any procedures requiring use
of contrast dye because it is nephrotoxic

Older adults are at increased risk for cardiac dysrhythmias due
to deteriorating heart structures