Flashcards Competency 12: Oxygenation and Perfusion

Two major divisions of the respiratory system

The upper airway and lower airway.

Structures included in the upper airway

The pharynx and larynx.

Function of the upper airway

It helps warm, filter, and humidify inspired air.

What is the pharynx?

The cavity behind the nose and throat.

What is the nasopharynx?

The portion of the pharynx associated with the nasal area.

What is the oropharynx?

The portion of the pharynx associated with the mouth/throat.

What is the larynx?

The structure at the top of the trachea that contains the vocal cords.

Structures that make up the lower airway

Trachea, bronchi, bronchioles, and alveoli.

Where does actual gas exchange occur?

The alveoli.

Number of lobes in the right lung

3 lobes.

Number of lobes in the left lung

2 lobes.

Why does the left lung have fewer lobes than the right?

Your ATI identifies the left lung as having two lobes but does not explain the reason in the supplied section.

What is the pleura?

A membrane that surrounds the lungs.

What is the pleural cavity?

The space between the pleural layers containing fluid that allows the lungs to expand and contract smoothly.

What does surfactant do?

Helps keep the alveoli from collapsing during exhalation.

What is atelectasis?

Collapse of lung tissue/alveoli, causing loss of lung volume.

Why are postoperative patients at risk for atelectasis?

General anesthesia and opioids can cause slow, ineffective breathing, decreasing lung expansion and gas exchange.

What muscles are primarily involved in breathing?

The diaphragm and intercostal muscles.

What happens to the diaphragm and intercostal muscles during inhalation?

They contract, increasing thoracic size and creating negative pressure that pulls air into the lungs.

What happens during exhalation?

The diaphragm and intercostal muscles relax, allowing air to leave the lungs.

What is ventilation?

The movement/flow of air into and out of the alveoli. (Ventilation = AIR)

What is perfusion?

The flow of blood to the alveolar capillaries. (Perfusion = BLOOD)

What is gas exchange?

The exchange of oxygen and carbon dioxide between the alveoli and blood.

What happens to oxygen during gas exchange?

Oxygen moves from the alveoli into the blood.

What happens to carbon dioxide during gas exchange?

CO₂ moves from the blood into the alveoli so it can be exhaled.

What carries most oxygen through the bloodstream?

Hemoglobin inside red blood cells.

Easiest way to distinguish ventilation from perfusion

Ventilation = air getting to the alveoli. Perfusion = blood getting to the alveoli.

Why do we need both ventilation and perfusion?

Air must reach the alveoli and blood must reach the alveolar capillaries for effective gas exchange.

What part of the body helps regulate breathing?

The brainstem.

What do respiratory chemoreceptors monitor?

Changes in CO₂ and O₂ in the blood.

Where are peripheral chemoreceptors located?

The aortic arch and carotid arteries.

Where are central chemoreceptors located?

The medulla oblongata in the brainstem.

What happens to respirations when the body needs more oxygen or needs to eliminate more CO₂?

Respiratory rate and depth increase.

Normal resting adult respiratory rate according to ATI

12-20 breaths/min.

What is pulmonary circulation?

Movement of deoxygenated blood from the heart to the lungs for oxygenation and then back to the heart.

Which side of the heart sends deoxygenated blood toward the lungs?

The right side.

What vessel carries deoxygenated blood toward the lungs?

The pulmonary artery.

Where does pulmonary gas exchange occur?

The pulmonary capillaries surrounding the alveoli.

What vessels return oxygenated blood to the heart?

The pulmonary veins.

Where does oxygenated blood enter the heart?

The left atrium.

Where does blood go after the left atrium?

Left ventricle → aorta → systemic circulation.

What is cardiac output (CO)?

The amount of blood pumped by the left ventricle in 1 minute.

What is the cardiac output formula?

CO = HR × SV

Expected cardiac output in a healthy resting adult according to ATI

3-6 L/min.

What is stroke volume?

The amount of blood ejected from the left ventricle with each contraction.

What three major factors affect stroke volume?

Preload, afterload, and contractility.

What is preload?

The amount of blood in the left ventricle at the end of diastole before contraction.

What is afterload?

The resistance the left ventricle must overcome to eject blood.

What is contractility?

The heart muscle's ability to contract/pump.

Four modifiable cardiopulmonary risk factors identified by ATI

Diet, exercise, smoking, and stress.

What are two nonmodifiable risk factors?

Age and family history.

How does smoking/nicotine interfere with oxygenation and perfusion?

Nicotine causes vasoconstriction, which decreases blood flow and increases blood pressure and heart rate.

Environmental exposures that can impair respiratory function

Pollution, secondhand smoke, dust, chemical vapors, fumes, and occupational exposures.

What is hyperventilation?

Increased rate and depth of breathing.

What happens to CO₂ during hyperventilation?

CO₂ decreases because too much is exhaled.

What happens to pH during hyperventilation?

pH increases → alkalosis. (Hyperventilation = blow OFF CO₂ → respiratory alkalosis)

What can cause hyperventilation according to ATI?

Anxiety attacks, pneumonia, COPD, asthma, DKA, and brain injury.

What manifestations can occur with hyperventilation?

Weakness, dizziness, headache, anxiety, tachycardia, difficulty breathing, and numbness/tingling of the fingers.

What is hypoventilation?

Shallow breathing with a lower-than-expected respiratory rate.

What happens to CO₂ during hypoventilation?

CO₂ increases.

What happens to pH during hypoventilation?

pH decreases → acidosis. (Hypoventilation = HOLD CO₂ → respiratory acidosis)

What can cause hypoventilation?

Neuromuscular disorders, barbiturates, narcotics, benzodiazepines, neurological disorders, trauma, COPD, and asthma.

What is hypoxemia?

Decreased oxygen in the blood.

What is hypoxia?

Lack of adequate oxygen at the cellular/tissue level. (Hypoxemia = BLOOD, Hypoxia = TISSUES)

Can hypoxemia lead to hypoxia?

Yes. Low oxygen in the blood can eventually result in inadequate oxygen reaching tissues.

Manifestations of hypoxemia/hypoxia

Confusion, irritability, restlessness, dyspnea, tachypnea, tachycardia or bradycardia, and cyanosis.

Additional respiratory signs that can indicate hypoxia

Accessory-muscle use, pursed-lip breathing, intercostal retractions, and nasal flaring.

Important early neurological clue of hypoxia

Restlessness/confusion.

What does cyanosis indicate?

Bluish discoloration associated with inadequate oxygenation.

What can cause hypoxia?

Smoke inhalation, high altitude, COPD, pneumonia, asthma, respiratory-depressing medications, anemia, decreased ventilation, poor tissue perfusion, or impaired diffusion.

Major physical-assessment techniques for the cardiopulmonary system

Inspection, palpation, percussion, and auscultation.

What should normal breathing look like?

Regular, quiet, and without obvious respiratory distress.

What should the nurse look for when inspecting a client with possible respiratory difficulty?

Accessory-muscle use, restlessness, cyanosis, abnormal breathing pattern, clubbing, edema, chest deformities, and tripod positioning.

What is the tripod position?

Sitting while placing the arms against the legs or another surface to assist breathing.

What is clubbing?

Enlargement of the fingertips with an increased angle between the nail and nail bed, associated with chronic cyanosis/pulmonary disease.

What does a barrel chest suggest?

It can be seen in clients with COPD.

What is tactile fremitus?

A vibration felt through the chest wall while the client speaks.

What can decrease tactile fremitus?

Accumulation of fluid or air, such as pleural effusion or pneumothorax.

Normal capillary refill according to this ATI module

No longer than 3 seconds.

What can prolonged capillary refill indicate?

Impaired circulation or oxygenation.

Normal breath sounds identified in this ATI section

Bronchial and vesicular sounds.

Where are bronchial sounds normally heard?

Over the trachea and bronchi.

Where are vesicular sounds normally heard?

Over the lung tissue.

What are adventitious breath sounds?

Abnormal breath sounds.

What do crackles sound like?

Popping/crackling.

What causes crackles?

Fluid filling the air sacs.

What conditions can produce crackles?

Pneumonia/infection.

What does wheezing sound like?

A whistling or musical sound, especially on exhalation.

What causes wheezing?

Constricted/narrowed airways.

What conditions can cause wheezing?

Asthma and COPD.

What do rhonchi sound like?

Rattling.

What causes rhonchi?

Airway obstruction.

What is stridor?

A wheezing-like sound caused by upper-airway constriction, heard on inhalation.

Why is stridor especially important?

Stridor is a medical emergency. (Crackles = FLUID, Wheeze = NARROW airway, Rhonchi = OBSTRUCTION/secretions, Stridor = UPPER AIRWAY EMERGENCY)

Percentage of oxygen present in room air

21%.

Is oxygen considered a medication?

Yes. Oxygen is considered a medication and requires a provider prescription.

Why is supplemental oxygen administered?

To treat hypoxemia, increase oxygen available to the alveoli, and potentially decrease work of breathing.

Oxygen saturation for healthy individuals in this oxygen-therapy section

95-100%.

Flow rate for a nasal cannula

1-6 L/min.

Oxygen concentration a nasal cannula can deliver

Approximately 24-44% oxygen.