Foundations- Chapter 39- Oxygenation and Perfusion PDF

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Foundations- Chapter 39- Oxygenation and Perfusion 

The demand for oxygen is met by the function of the respiratory and cardiovascular systems, also known as the cardiopulmonary system



Oxygenation  the process of providing life-sustaining oxygen to the body’s cells

Anatomy and Physiology of Oxygen 

Oxygenation of body tissues depends on several factors o Integrity of the airway system to transport air to and from the lungs o Properly functioning alveolar system in the lungs to oxygenate venous blood and to remove carbon dioxide from the blood o Properly functioning cardiovascular system and blood supply to carry nutrients and wastes to and from body cells

Respiratory System 

Oxygen and carbon dioxide must move through the alveoli as part of the oxygenation process

Anatomy of the Respiratory System 

The airway, which begins at the nose and ends at the terminal bronchioles, is a pathway for the transport and exchange of oxygen and carbon dioxide o Upper Airway  warm, filter, and humidify inspired air 

Nose



Pharynx



Larynx

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Epiglottis

o Lower Airway  conduction of air, mucociliary clearance, and production of pulmonary surfactant 

Trachea

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Right and left main stem bronchi

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Segmental bronchi

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Terminal bronchioles

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Cilia  microscopic hair-like projections

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Alveoli  small air sacs o Site of gas exchange

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Surfactant  detergent like phospholipid, reduces the surface tension between the moist membranes of the alveoli, preventing their collapse

Physiology of the Respiratory System

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Gas exchange, the intake of oxygen and the release of carbon dioxide, is made possible by pulmonary ventilation, respiration, and perfusion o Pulmonary Ventilation  movement of air into and out of the lungs o Respiration  gas exchange between the atmospheric air in the alveoli and blood in the capillaries o Perfusion  process by which oxygenated capillary blood passes through body tissue

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Pulmonary Ventilation o Movement of air into and out of the lungs o Two phases 

Inspiration (inhalation) 

Active phase

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Involves movement of muscles and the thorax to bring air into the lungs

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Increased lung volume and decreased intrapulmonic pressure allows atmospheric air to move from an area of greater pressure (outside air) into an area of lesser pressure (within the lungs)

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Expiration (exhalation) 

Passive phase

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Movement of air out of the lungs

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Decreased volume in the lungs and an increase in intrapulmonic pressure o Air in the lungs moves from an area of greater pressure to one of lesser pressure and is expired

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Respiration o Occurs at the terminal alveolar capillary system o Diffusion  movement of gas or particles from areas of higher pressure or concentration to areas of lower pressure or concentration 

In respiration, it is the movement of oxygen and carbon dioxide between the air and the blood

o Incomplete lung expansion or the collapse of alveoli, known as atelectasis, prevents pressure changes and the exchange of gas by diffusion in lungs 

Perfusion

o Oxygenated capillary blood passes through the tissues of the body in the process called profusion Alterations in Respiratory Function 

Hypoxia  a condition in which an inadequate amount of oxygen is available to cells o Most common symptom of hypoxia is dyspnea 

Dyspnea  difficulty breathing; elevated blood pressure with a small pulse pressure, increased respiratory and pulse rates, pallor, and cyanosis



Anxiety, restlessness, confusion, and drowsiness are also common signs

o Hypoxia is often caused by hypoventilation (decreased rate or depth of air movement into the lungs) 

Chronic Hypoxia o Affects all body systems 

Altered thought process

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Headaches

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Chest pain

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Enlarged heart

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Clubbing of the digits

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Anorexia

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Constipation

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Decreased urinary output

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Decreased libido

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Muscle pain and weakness

Anatomy of the Cardiovascular System 

The cardiovascular system is composed of the heart and the blood vessels

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The heart is the main organ of circulation o The continuous one-way circuit of blood through the blood vessels, with the heart as the pump

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Atria  upper chambers; receive blood from the veins

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Ventricles  lower chambers; force blood out of the heart through the arteries

Physiology of the Cardiovascular System

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Blood is squeezed through the heart and out into the body by contractions starting in the atria, followed by contractions of the ventricles, with a subsequent resting of the heart

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Deoxygenated blood is carried from the right side of the heart to the lungs, where oxygen is picked up and carbon dioxide is released, and then returned to the left side of the heart

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Oxygenated blood is pumped out to all other parts of the body and back again

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Average amount of blood pumped out in a healthy adult is 3.5 to 8.0 L/min o Volume is determined by: CO = SV x Heart Rate

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Internal Respiration  the exchange of oxygen and carbon dioxide between the circulating blood and the tissue cells

Regulation of the Cardiovascular System 

Sinoatrial (SA) Node  mass of tissue in the upper right atrium, just below the opening of the superior vena cava o Initiates the transmission of electrical impulses, causing contraction of the heart at regular intervals o AKA: pacemaker

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Atrioventricular (AV) Node  mass of tissue located at the bottom of the right atrium o When impulse reaches AV node, it enters a group of fibers called the atrioventricular bundle, or bundle of His 

Divides left and right branches

Alterations in Cardiovascular Function 

If a problem exists in the cardiovascular system, alterations in function of the heart may occur, leading to impaired oxygenation

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Dysrhythmia  or arrhythmia is a disturbance of the rhythm of the heart o Caused by abnormal rate of electrical impulse generation from the SA node, or from impulses originating from a site or sites other than the SA node

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Ischemia  decreased oxygen supply to the heart caused by insufficient blood supply, can lead to impaired oxygenation of tissues in the body o Caused by atherosclerosis, the accumulation of fatty substances and fibrous tissue in the lining or arterial blood vessel walls, creating blockages and narrowing the vessels, reducing blood flow

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Angina  temporary imbalance between the amount of oxygen needed by the heart and the amount delivered to the heart muscles, causing chest pain or discomfort

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Heart Failure  heart is unable to pump a sufficient blood supply, resulting in inadequate perfusion and oxygenation of tissues o Symptoms: shortness of breath, edema (swelling), and fatigue

Factors Affecting Cardiopulmonary Functioning and Oxygenation 

Level of Health o Acute o Chronic 

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Muscle wasting and poor muscle tone

Developmental Considerations o Infants (birth – 1 year)  small chest, short airways 

More rapid than any other age

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Pulse rate is more rapid

o Toddlers, Preschoolers, School-Aged Children, Adolescents 

Most children at this age have colds or upper respiratory infections, but some have more serious problems of otitis media, bronchitis, and pneumonia

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A child’s blood vessel widens and increase in length over time

o Older Adults 

The tissues and airways of the respiratory tract become less elastic 

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Airways collapse more easily

Increase the risk for disease, especially pneumonia and other chest infections

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Decreased physical activity, physical deconditioning, decreased elasticity of the blood vessels, and stiffening of the heart valves can lead to a decrease in the overall function of the heart

Respiratory Variations in the Life Cycle Infant (Birth – 1 Early Childhood

Late Childhood

Older Adult

Respiratory

Year) 20-40

(1-5 Years) 25-32

(6-12 Years) 18-26

(65+ Years) 16-24

Rate Respiratory

breaths/min Abdominal

breaths/min Abdominal

breaths/min Thoracic

breaths/min Thoracic,

Pattern

breathing,

breathing,

breathing,

regular

irregular in rate

irregular

regular

and depth Thin, little

Same as

Further

Thin, structures

muscle, ribs,

infant’s but

subcutaneous

prominent

and sternum

with more

fat deposited,

easily seen

subcutaneous

structures less

Breath

Loud, harsh

fat Loud, harsh

prominent Clear

Sounds

crackles at end

expiration

inspiration is

of deep

longer than

longer than

inspiration Round

inspiration Elliptical

expiration Elliptical

Chest Wall

Shape of 

Thorax Medication Considerations

Clear

Barrel shaped or elliptical

o Patients receiving drugs that affect the central nervous system need to be monitored carefully for respiratory complications o Other medications decrease heart rate, with the potential to alter the flow of blood to body tissues 

Lifestyle Considerations o Regular physical activity provides many health benefits, including increased heart and lung fitness, improved muscle fitness, and reducing the risk of heart disease o Cultural influences can also play a role in a person’s lifestyle, encouraging or discouraging healthy choices o An understanding of a patient’s cultural background is necessary to promote health and disease prevention in any population

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Environmental Considerations o Researchers have demonstrated a high correlation between air pollution and cancer and lung diseases

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Physiological Health Considerations o People responding to stress may sigh excessively or exhibit hyperventilation (increased rate and depth of ventilation, above the body’s normal metabolic requirements) o Generalized anxiety has been shown to cause enough bronchospasm to produce an episode of bronchial asthma

The Nursing Process for Oxygenation 

Assessment o The nursing examination combined with laboratory findings can provide information to identify a patient’s strengths; the nature of any problems; their course; related signs and symptoms; what problems can be treated independently by nursing o Nursing History 

Current and past respiratory problems

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Lifestyle, risk facts for impaired oxygen status

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Presence of cough and sputum or pain

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Medications for breathing

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Interview questions help identify current or potential health deviations, actions performed by the patient for meeting cardiopulmonary needs, and the effects of such actions

o Physical Examination 

Nurse observes rate, depth, rhythm, and quality of respirations

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Inspects variations of shape of thorax

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Always proceed in a well-organized manner through a sequence of inspection, palpation, percussion, and auscultation

o Inspection 

Observe the patient’s general appearance

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Note the patient’s level of consciousness and orientation to person, place, and time

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Inspect the patient’s skin, mucous membranes, and general circulation 

Pallor (lack of color)  indicates less than optimal oxygenation

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Cyanosis (bluish discoloration)  indicates decreased blood flow or poor blood oxygenation

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Note any abnormalities in the structures of the chest 

Kyphosis (curvature of the spine)  contributes to the older adult’s appearance of leaning forward and can limit respiratory ventilation

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Normally, respirations are quiet and nonlabored, and occur at a rate of 12 to 20 times each minute in healthy adults

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Tachypnea  rapid breathing

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Bradypnea  slow breathing

o Palpation 

Palpate the chest 

Note skin temperature and color

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Asses chest expansion, should be symmetrical

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Note the presence or absence of masses, edema, or tenderness on palpation

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Palpate extremities

o Percussion 

Used to assess the position of the lungs, density of lung tissue, and identify changes in the tissue

o Auscultation 

Assess air flow through the respiratory passages and lungs

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Normal Breathing 

Vesicular  low-pitches, soft sounds heard over peripheral lung fields

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Bronchial  loud, high-pitches sounds heard primarily over the trachea and larynx

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Bronchovesicular  medium pitched blowing sounds heard over the major bronchi

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Auscultate as patient breathes slowly through an open mouth 

Breathing through the nose can produce falsely abnormal breath sounds

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Listen for adventitious sounds (extra, abnormal sounds of breathing), such as wheezing or crackles 

Crackles  frequently heard on inspiration o Soft, high-pitched discontinuous (intermittent) popping sounds o Produced by air passing through fluid in the airways or alveoli and opening of delated small airways and alveoli o Occur due to inflammation or congestion and are associated with pneumonia, heart failure, bronchitis, and COPD

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Wheezes  continuous musical sounds, produces as air passes through airways constricted by swelling, narrowing, secretions, or tumors

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Auscultation of the heart assess function of the heart, heart valves, and blood flow. 

“lub-dub” o Lub = systole o Dub = diastole

Common Diagnostic Tests 

Electrocardiography o Measures the heart’s electrical activity o Electrocardiogram (ECG)  electrodes attached to the skin can detect these electric currents and transmit them to an instrument that produces a record 

Used to identify myocardial ischemia and infarction, heart damage, rhythm and conduction disturbances, chamber enlargement, electrolyte imbalances, and drug toxicity

o Measures and averages the differences between the electrical potential of the electrode sites for each lead and graphs them over time 

Pulmonary Function Studies o Encompass a group of tests used to assess respiratory function to assist in evaluating respiratory disorders o Provide an evaluation of lung dysfunction, diagnose disease, assess disease severity, assist in management of disease, and evaluate respiratory interventions o Tests and their purposes: 

Diffusion capacity estimates the patient’s ability to absorb alveolar gases and determine if a gas exchange problem exists

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Maximal respiratory pressures help evaluate neuromuscular causes of respiratory dysfunction

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Exercise testing helps evaluate dyspnea during exertion

o Commonly Measured Values from Pulmonary Function Tests 

Tidal Volume (TV): Total amount of air inhaled and exhaled with one breath

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Vital Capacity (VC): Maximum amount of air exhaled after maximum inspiration

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Forced Vital Capacity (FVC): Maximum amount of air that can be forcefully exhaled after a full inspiration

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Total Lung Capacity (TLC): The amount of air contained within the lungs at maximum inspiration

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Residual Volume (RV): The amount of air left in the lungs at maximal expiration

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Peak Expiratory Flow Rate (PEFR): The maximum flow attained during the FVC

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Spirometry o Measures the volume of air in liters exhaled or inhaled by a patient over time o Used to measure the degree of airway obstruction and evaluates response to inhaled medications o Spirometer  an instrument that measures lung volumes and airflow

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Peak Expiratory Flow Rate o Refers to the point of highest flow during forced expiration o Produces a measurement in liters indicating the maximum flow rate during a forced expiration o Normal values are established in regard to height, age, and biological sex, as well as individual baseline values for patients with disease

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Pulse Oximetry o A noninvasive technique that measures the arterial oxyhemoglobin saturation (SpO2) of arterial blood o Useful for monitoring patients receiving oxygen therapy, titrating oxygen therapy, monitoring those at risk for hypoxia, and monitoring postoperative patients o A range of 95% to 100% is considered normal SpO2; values < or = 90% are abnormal, indicate that oxygenation to the tissues is inadequate and should be investigated for potential hypoxia or technical error

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Capnography o A method to monitor ventilation and indirectly, blood flow through the lungs o Exhaled air passes through a sensor that measures the amount of carbon dioxide (CO2) exhaled with each breath

o Can detect signs of hypoventilation earlier than pulse oximetry 

Thoracentesis o Procedure of puncturing the chest wall and aspirating pleural fluid o May be performed to obtain a specimen for diagnostic purposes or to remove fluid that has accumulated in the pleural cavity and is causing respiratory difficulty and discomfort o The location where the needle is inserted depends on where the fluid is present and where the practitioner can best aspirate it o The maximum amount of fluid removed is generally 1,000 mL o A chest radiograph is usually done after the procedure to verify the absence of complication

Diagnosing 

Alterations in Oxygenation as the Problem o Examples of nursing diagnoses indicating alterations in oxygenation include:

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Ineffective Airway Clearance

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Ineffective Breathing Pattern

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Impaired Gas Exchange

Alterations in Oxygenation as the Etiology o May affect other areas of human functioning o Examples of nursing diagnoses for whi...