Oxygenation Chapter 35 Flashcards
What happens to inhaled air in the airways? How does this occur?
Answer:
The airway structures moisten, warm, and filter inhaled air. This is accomplished in three ways:
● A moist mucous-membrane lining adds water to inhaled air.
● Blood flowing through the vessels of airway walls transfer body heat to the inhaled air.
● Tiny hairlike projections from the wall of the airways (cilia) move rhythmically to carry trapped debris up and out of the airway.
Pulmonary System
Airways and Lungs
Ventilation
Movement of air into/out of the lungs
Respiration
Exchange of oxygen/carbon dioxide
Which diagnostic test/exam would best measure a client’s level of hypoxemia?
a. chest x-ray
b. pulse oximeter reading
c. ABG
d. peak expiratory flow rate
c. ABG
Cardiovascular System
Heart, blood vessels, red blood cells
Hemoglobin: carries oxygen
Arteries
• Oxygenated blood to tissues
Veins
• Deoxygenated blood back to heart/lungs
Tissue Paper My Assets
From the Body flows to the
Tricuspid
Then to the
Pulmonic
Out to the lungs, back in from the lungs to the
Mitral
Then to the
Aortic
and out to the body
Factors That Influence Oxygenation
Lifespan and development (e.g., respiratory distress syndrome, upper respiratory infections (URIs), adolescent smoking, cardiac insufficiency)
Environment (e.g., stress, allergies)
Lifestyle (e.g., nutrition, exercise, substance abuse)
Medications
Pathophysiological Conditions
Neuromuscular abnormalities
Cardiovascular abnormalities
• Heart disease
• Vessel disease
Oxygen transport problems
Metabolic problems
Pathophysiological Conditions
Alterations in O2 and CO2 levels
Alterations in
Pulmonary system: structure, airways, tissue
Pulmonary circulation
Assessing Oxygenation Status
Physical Examination
Breathing pattern
Respiratory effort
Pulse oximetry
Cardiac functioning
Using inspection, palpation, percussion, and auscultation
The term “Kussmaul” refers to a high-pitched, harsh, crowing inspiratory sound that occurs due to partial obstruction of the larynx.
a. true
b. false
Correct answer: B, false
The term for this sound of respiratory distress is “stridor.”
Assessing Oxygenation Status
Diagnostic Testing
Arterial blood gases (ABGs)
PO2, PCO2
Peak flow monitoring
Cardiac monitoring: electrocardiogram
Normal Range for Hemoglobin
12-18
Hematocrit Levels
Men = 40-54%
Women 36-46%
Newborn = 44-64%
Normally 3x the hemoglobin
Measures the % of RBC in whole blood
Interventions for Optimal Oxygenation
Use of a mechanical ventilator
Use of chest tube drainage
systems
Promoting circulation
Administering respiratory medications
Promoting Respiratory Function
Immunizations/prevent URIs
Positioning: maximum lung excursion
Incentive spirometry
Aspiration precautions
Mobilizing secretions
• Deep breathing and coughing
• Hydration
• Chest physiotherapy
Oxygen therapy
• Cannula
• Mask
• Transtracheal catheter
Using artificial airways
- Oropharyngeal
- Nasopharyngeal
- Endotracheal tubes
- Tracheostomy tube Artificial airway patency
• Suctioning
•
•
ClickerCheck
In caring for a client with a tracheostomy, the nurse would give priority to the nursing diagnosis of
a. Risk for ineffective airway clearance
b. Anxiety related to suctioning
c. Social isolation related to altered body image
d. Impaired tissue integrity
Correct answer: A
While other diagnoses may be applicable, maintaining a patent airway by tending to excessive secretions is a priority.
In which structures of the lung does gas exchange take place?
Answer:
Gas exchange takes place in the type I alveolar cells.
What does surfactant do for alveoli?
Answer:
Surfactant is the substance that lowers the surface tension inside alveoli and prevents their walls from being drawn together. Adequate surfactant levels are key to preventing alveolar collapse and allowing alveolar expansion during breathing.
What is the difference between ventilation and respiration?
Answer:
Ventilation and respiration have the following differences:
● Ventilation is the movement of air into and out of the lungs through the act of breathing.
● Respiration is gas (carbon dioxide and oxygen) exchange.
Describe how the diaphragm, accessory muscles, and pressure changes within the lungs create inhalation and exhalation.
Answer:
The diaphragm is the major muscle of breathing. Inhalation begins when the diaphragm contracts and the chest cavity is pulled downward. The lung bases descend with the chest cavity, significantly enlarging the lungs. Intercostal muscles, the small muscles around the ribs, also contract and pull the ribs slightly outward, expanding the chest cavity and lungs. The overall effect is to enlarge the chest cavity and subsequently the lungs. The negative pressure created in the lungs draws air in through the only opening to the outside, the trachea. Exhalation occurs when the diaphragm and intercostals muscles relax, allowing the chest and lungs to return to their normal resting size. The reduction in size causes a rise in pressure inside the chest and lungs to above atmospheric pressure, which causes air to flow out of the lungs. Exhalation requires no energy or effort.
How does hypoventilation affect risk for hypoxemia and hypoxia?
Answer:
Hypoventilation occurs when a small amount of air is moved into and out of the lungs, which is caused by a decreased rate and/or depth of breathing. Hypoventilation increases the risk for problems with oxygenation (hypoxemia) and perfusion (hypoxia).
Describe two ways in which breathing is controlled.
Answer:
● Chemoreceptors located in the medulla of the brainstem, the carotid arteries, and the aorta detect changes in blood pH, O2, and CO2 levels, and they send messages back to the central respiratory center in the brain stem. In response, the respiratory center increases or decreases ventilation to maintain normal blood levels of pH, O2 (pO2), and CO2 (pCO2). Normally the blood CO2 level provides the primary stimulus to breathe. High CO2 levels stimulate breathing to eliminate the excess CO2.
● A secondary, though important, drive to breathe is hypoxemia. Low blood O2 levels stimulate breathing to get more oxygen into the lungs.
● In addition, lung receptors, located in the lung and chest wall, are sensitive to breathing patterns, lung expansion, lung compliance, airway resistance, and respiratory irritants. The respiratory center uses feedback from the lung receptors to adjust ventilation.
● Voluntary control from the motor cortex can override the involuntary respiratory centers, but only temporarily.
The level of which gas (oxygen or carbon dioxide) is the primary stimulant for breathing?
Answer:
Carbon dioxide
What are the major risks to oxygenation related to developmental factors?
Answer:
Children and adults have the following major risks factors related to oxygenation:
● Children. Incomplete development of the lungs and immune system place infants and young children at increased risk for problems with oxygenation. Increasing motor skills that are not accompanied by knowledge of risks also place young children at risk for aspiration and drowning.
● Older adults. The effects of aging also influence oxygenation. Costal cartilage begins to calcify, making the chest wall gradually less mobile and more rigid, reducing chest wall movement during breathing. The lungs have less recoil ability, and the alveoli lose elasticity. These changes result in reduced lung expansion and less alveolar inflation, especially in the bases of the lungs. The cough reflex is less effective, and the number of cilia in the airways decline with aging, making it more difficult to expel mucus or foreign material. Exhalation becomes less efficient, causing progressive air trapping, which decreases the ability to increase ventilation when oxygenation demands increase (as with exercise). The immune response declines with aging, especially cell-mediated immunity, T-cell activity, and the inflammatory response. All of these changes put elders at risk for respiratory infections.
What environmental and lifestyle factors that influence ventilation and circulation can be avoided or minimized?
Answer:
The following environmental and lifestyle factors that influence ventilation can be avoided:
● Poor nutrition
● Obesity
● Sedentary lifestyle
● Smoking
● Substance abuse
To a lesser extent, exposure to poor air quality, altitude, temperature extremes, and stress can be minimized.
What are some indirect indicators of tissue oxygenation?
Answer:
Adequacy of tissue oxygenation can be indirectly assessed by determining whether organs are functioning normally. For example, hypoxic central nervous system tissue causes abnormal brain functioning (e.g., altered level of consciousness), whereas hypoxic renal tissue causes abnormal kidney functioning (e.g., poor urine output), and hypoxic limb tissue results in abnormal muscle functioning (e.g., muscle weakness and pain with exercise).
How are hyperventilation and hypoventilation related to carbon dioxide levels?
Answer:
Ventilation relates to carbon dioxide levels in the following ways:
● Hypoventilation causes an excess of dissolved carbon dioxide in the blood, called hypercarbia (also called hypercapnia).
● Hyperventilation causes a low level of dissolved carbon dioxide in the blood, called hypocarbia (also called hypocapnia).
What are the effects of carbon dioxide levels on the nervous system?
Answer:
Carbon dioxide levels affect the nervous system in the following ways:
● Very high blood levels of carbon dioxide have an anesthetic effect on the nervous system and can lead to somnolence progressing to coma and death, a syndrome known as carbon dioxide narcosis.
● Very low blood levels of carbon dioxide have a stimulating effect on the nervous system and lead to muscle twitching or spasm (especially in the hands and feet) and numbness and tingling in the face and lips.
How are hyperventilation and hypoventilation related to carbon dioxide levels?
Answer:
Ventilation relates to carbon dioxide levels in the following ways:
● Hypoventilation causes an excess of dissolved carbon dioxide in the blood, called hypercarbia (also called hypercapnia).
● Hyperventilation causes a low level of dissolved carbon dioxide in the blood, called hypocarbia (also called hypocapnia).
What are the effects of carbon dioxide levels on the nervous system?
Answer:
Carbon dioxide levels affect the nervous system in the following ways:
● Very high blood levels of carbon dioxide have an anesthetic effect on the nervous system and can lead to somnolence progressing to coma and death, a syndrome known as carbon dioxide narcosis.
● Very low blood levels of carbon dioxide have a stimulating effect on the nervous system and lead to muscle twitching or spasm (especially in the hands and feet) and numbness and tingling in the face and lips.
Identify four pathophysiological conditions that affect pulmonary function. How are they similar? How are they different?
Answer:
The following types of conditions affect ventilation and oxygenation.
● Pulmonary system abnormalities, such as structural alterations, inflammation, obstruction, infection, alveolar–capillary membrane disorders, or collapse of alveoli, affect ventilation and gas exchange.
● Pulmonary circulation abnormalities, such as pulmonary embolus and pulmonary hypertension, can disrupt gas exchange.
● Neuromuscular abnormalities can affect gas exchange by interfering with the regulation of breathing or limiting movement of the muscles involved with breathing. Any condition that causes injury to the CNS or alters CNS function can interfere with the regulation of breathing.
These conditions are similar in that each of these conditions affects oxygenation.
They differ as to whether they affect ventilation, gas exchange, or gas transport.
They also differ in that some affect structure of the pulmonary or cardiovascular systems, and others affect function of these systems.
What types of injuries are most likely to cause oxygenation problems?
Answer:
Three types of injuries are most likely to be associated with oxygenation problems:
● Injuries to the chest wall
● Injuries to the CNS that may affect regulation of breathing
● Injuries that may be associated with embolus formation
What areas should you include in a nursing history for a patient with oxygenation concerns who is undergoing a comprehensive assessment?
Answer:
For a patient with oxygenation concerns, six areas need to be assessed:
● Demographic data
● Health history
● Respiratory history
● Cardiovascular history
● Environmental history
● Lifestyle