MEDICAL SURGICAL NURSING CHAPTER 28

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MEDICAL SURGICAL NURSING CHAPTER 28

• INTRO TO THE CARDIOVASCULAR SYSTEM

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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

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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

• Epicardium-outer layer
• Myocardium-middle layer
• Endocardium-inner layer, smooth
• Pericardium-a sac that surrounds the heart made
  up of 2 layers
• parietal layer tough, outer
• visceral layer smooth, adheres to the heart
  itself

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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

• ARTERIES carry oxygenated blood from the heart
• VEINS carry deoxygenated blood to the heart

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

• Oxygenated blood comes back into the lt atrium
  through the aortic valve pulmonary veins
• Then through the bicuspid valve/ mitral valve
  into the lt ventricle
• Lt ventricle pumps the oxygenated blood through
  the aorta to the rest of the body

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BLOOD SUPPLY TO THE HEART

• 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

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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
• Starlings law-the greater the stretch of the
  myocardium the stronger is the ventricular
  contraction- like the rubber band being stretched.

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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

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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

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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

• Chemoreceptors
• sensitive to pH, CO2 O2 blood levels
• located in carotid bodies, aortic bodies
  medulla
• Box 28-1 factors that alter heart rate

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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 bodys changing needs
• Stroke volume amount of blood pumped with each
  heart contraction
• Cardiac Output heart rate x stroke volume

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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

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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

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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

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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

• Lung sounds clear, crackles, wheezes, gurgles,
  heart failure
• Sputum productive or non productive cough,
  appearance of sputum
• Mental Status confusion disorientation signs
  of poor brain oxygenation

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DIAGNOSTIC TESTING

• Blood chemistry FBS, electrolytes, cholesterol
  triglycerides
• Serum enzymes isoenzymes specific to damage
  of heart muscle
• troponin
• creatine kinase (CK)
• LDH
• AST

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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

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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

• Ambulatory EKG
• Exercise-induced stress testing evaluates how
  the heart does during exercise
• Drug-induced stress testing drugs such as
  adenocard, persantine or dobutrex used to stress
  the heart for those who cannot tolerate the
  exercise stress test

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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

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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

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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

• Pulmonary artery monitoring assesses pressures
  cardiac output. Cath placed peripherally into
  the rt or lt pulmonary artery fig 28-16
• Nursing Process diagnostic procedures of the CV
  system

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GENERAL NUTRITIONAL CONSIDERATIONS

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

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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 pts 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

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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