Circulation

• Components of the cardiovascular system

  • Heart
  • Blood
  • Blood Vessels
  • Arteries
  • Veins
  • Capillaries

  
• Type of Blood Vessels

  • Figure

  
• Layers of the Heart Wall

  • Figure

  
• The Types of Ventricles and Atriums of the Heart

  • Figure
• Layers of the Artery Wall


  • Figure

  
• Pathway of Blood through Heart and Lungs

  1. Right atrium

  2. Tricuspid valve

  3. Right ventricle

  4. Pulmonary semilunar valve

  5. Pulmonary arteries

  6. Lungs

  7. Pulmonary veins

  8. Left atrium

  9. Bicuspid valve

  10. Left ventricle

  11. Aortic semilunar valve

  12. Aorta

  13. Systemic circulation

  
• Types of blood

  • Oxygen-rich blood
  • Oxygen-poor blood
• Systole


  Heart ejects (propels) blood into the pulmonary and systemic circulation

  
• Diastole


  • Ventricles filled with blood
  • All heart muscle in relaxation
  • All heart valves are closed
  • Blood returning to atria

  
• Atrial Systole


  • Atria in contraction
  • AV valves are open
  • Blood to ventricles

  
• Ventricular Systole


  • Ventricles in contraction
  • Semilunar valves are open
  • Blood passing to arteries

  
• Automaticity


  Can generate electrical impulses and contractions independently of the nervous system
• Heartbeat


  Contraction and relaxation of the heart (60-100/minute)
• Cardiac Output


  The amount of blood pumped by the ventricles in 1 minute, an indicator of how well the heart is functioning
• Stroke Volume


  The volume of blood pumped out of the left ventricle of the heart during each systolic cardiac contraction

  
• Factors affecting cardiac output

  • Heart Rate
  • Preload
  • Contractility
  • Afterload
• How the heart pumps blood


  • The heart is made of muscle that contracts (squeezes) and relaxes
  • The two atria contract and relax, then the two ventricles contract and relax
  • This is how blood moves through the heart and is pumped to the lungs and the body
  • One complete sequence of contraction and relaxation is called a heartbeat

  
• Hemodynamic factors affecting blood flow

  • Blood pressure
  • Resistance (viscosity, length of the vessels, diameter)
  • Venous return (gravity/skeletal muscle)

  
• Hormonal regulation of circulation

  • Renin angiotensin-aldosterone mechanism
  • Epinephrine and norepinephrine
  • Antidiuretic hormone
  • Atrial natriuretic peptide
• Factors affecting cardiovascular function

  • Age/heredity/gender
  • Elevated serum lipid levels
  • Hypertension/diabetes
  • Cigarette smoking
  • Obesity
  • Sedentary lifestyle
  • Heat and cold
  • Health status
  • Stress and coping
  • Diet
  • Elevated homocysteine level (vitamin deficiency)
  • Sclerosis and thickening of valve flaps
  • Decline in cardiac reserve
  • Fibrosis of cardiac muscle
  • Atherosclerosis
• Stimuli causing autoregulatory changes

  • Physical change (injury, diseases, adaptation, aging)
  • Vasodilating chemicals (nitrous oxide, prostaglandins, bradykinin, histamine, adenosine), food (leafy green vegetables, pomegranate, beets, watermelon, citrus foods, garlic, dark chocolate)
  • Vasoconstricting chemicals (endothelin, epinephrine, norepinephrine, vasopressin, angiotensin II), food (caffeine, sodium-rich foods, tyramine rich foods, alcohol, trans fat, MSG, high sugar food)
• Blood


  • Complex mixture of living formed elements (blood cells), suspended in fluid (plasma)
  • Primary functions: transport O2, nutrients, hormones, and waste products; regulate body temperature, pH, and fluid volume; prevent infection and blood loss

  
• Hemoglobin


  • Major component of RBC that binds with oxygen
  • The higher the PO2, the greater affinity to O2
  • Higher temperature, low pH and high PCO2 - affinity for O2 decreases, leading to fatigue and activity intolerance
• Alterations in cardiovascular functions

  • Myocardial infarction (MI)/heart attack
  • Heart failure
  • Impaired tissue perfusion
  • Blood alterations

  
• Myocardial infarction (MI)/heart attack


  • Vessel that supplies blood to the heart muscle may become occluded by atherosclerosis or blood clot, shutting off blood supply to a portion of the myocardium
  • Signs and symptoms: chest pain, substernal and/or radiating to the left arm and jaw; nausea; shortness of breath; diaphoresis

  
• Heart failure


  • Develop if the heart isn't able to keep up with the body's need for oxygen and nutrients to the tissues
  • Develop from MI or uncontrolled hypertension or extensive arteriosclerosis
  • Signs and symptoms: pulmonary congestion/adventitious lung sounds; shortness of breath; increased heart rate/RR; peripheral vasoconstriction; pale extremities; distended neck veins
• Impaired tissue perfusion


  Signs of impaired peripheral arterial circulation: decreased peripheral pulses; pale skin color; cool extremities; decreased hair distribution
• Blood alterations

  • Inadequate RBC
  • Low hemoglobin
  • Abnormal tissue oxygenation
  • Diet deficient in iron and folic acid
  • Immature hemoglobin and RBC
  • Blood volume (hemorrhage, severe dehydration)
• Other diseases that can decrease cardiac output


  • Very irregular/excessively rapid or slow heart rate/dysrhythmias
  • Congenital heart defects/bacterial endocarditis/rheumatic fever
  • Scarred and stenotic valves/mitral insufficiency

  
• Nursing health history

  • Current and past cardiovascular problems
  • Family history (HPN, increased cholesterol level and stroke)
  • History of diabetes and respiratory disorder
  • Exercise program
  • History of cigarette smoking
  • Diet (fat and salt intake, alcohol intake, caffeine, soft drinks and chocolates)
  • Presence of any symptoms - pain, DOB, fatigue, palpitations, cough, and fainting
  • Medications for heart, blood pressure, circulation, and cholesterol
  • Lifestyle including social support, stressors, and methods of coping
• Physical assessment


  • Evaluate BP for both arms/palpate peripheral pulses for strength and quality
  • Assess lung sounds for adventitious sounds
  • Assess skin color, temperature, hair distribution, lesions and edema
  • Ankle/Brachial Index (ABI) (0.9-1.4)
  • Toe Brachial Index (TBI) (0.87)
• Diagnostic studies

  • Cardiac monitor
  • ECG (Electrocardiography) - 12 leads
  • Blood test: CBC (Hemoglobin, RBC), serum electrolytes, Creatinine Kinase (CK), troponin I, hemodynamic studies (Fluid status and cardiovascular function)
• Nursing diagnoses


  • Ineffective Tissue Perfusion
  • Decreased cardiac output
  • Activity Intolerance
• Nursing interventions


  • Vascular: Position with legs elevated, encourage leg exercise, encourage/provide slow frequent position change
  • Cardiac: Position client in high Fowlers position, monitor intake and output
  • Medications: Nitrates, ACE inhibitors, positive ionotropic drugs, beta adrenergic blocking agents, diuretics
• Assess for serum sodium potassium after giving diuretics
• Check BP, HR, RR, lung sounds, and peripheral pulses before giving positive ionotropic drugs
• Check BP before giving antihypertensives
• Preventing venous stasis

  • Sequential compression device
  • Antiembolic stocking
• Basic life support


  • Oral resuscitation (mouth-to-mouth breathing)
  • External cardiac massage (chest compression)
• Cardiac arrest


  • Cessation of cardiac function
  • 20-40 seconds - clinically dead
  • 4-6 minutes - permanent and irreversible damage to the brain
  • Cardinal signs: apnea, absence of carotid and femoral pulse, dilated pupils