Cardiopulm Unit 6 Pulmonary Anatomy/Physiology and Examination Flashcards
What is Ventilation?
This refers to the delivery system that presents oxygen‐rich air to the alveoli and removes CO2 from the blood/alveoli
What are the Clinical Signs that can be use to evaluate the adequacy of ventilation at bedside?
Chest Rise and Respiratory Rate
With ventilation, what is CO2 levels affected by?
CO2 leve ls are mainly affected by Minute Ventilation which can be described as the amount of air that ventilated per breath (tidal volume) and the rate of breathing (TIDAL VOLUME x RESPIRATORY RATE)
What is Oxygenation?
The patient’s ability to take in oxygen from the alveoli and distribute it to the tissues and organs of the body to maintain cellular activity.
With Oxygenation,what is the difference between Hypoxia and Hypoxemia?
- Hypoxia refers to the end-result of insufficient oxygen delivery to the tissues. While not directly measurable, it is clinically suspected through different types of blood analyses and via clinical signs suggesting organ ischemia
- Hypoxemia refers specifically to low levels of oxygen in the blood. It is measured by SaO2 and SpO2. Saturation of peripheral oxygen levels measured with a pulse oximeter (SpO2) correlate highly with actual arterial oxygenation concentrations (SaO2). SaO2 tells us the percentage of hemoglobin in the blood that is fully loaded with oxygen
What is Respiration? What is Respiratory Failure?
A general term that refers to the action of breathing via the combination of ventilation and oxygenation. It is the biochemical process of both taking in oxygen and removing carbon dioxide.
- “Respiratory Failure” is a medical diagnosis that can refer to either an issue with oxygenation and/or inadequate carbon dioxide removal.
What do neurons of the brainstem (including the medulla oblongata and pons) provide?
Control for automatic breathing and adjust ventilatory rate and tida volume for normal gas exchage
What are Chemoreceptors responsible for?
Sensing alterations in Blood pH, CO2, and O2 levels
What normal ventilation driven by?
Normal ventilation is driven mostly by the levels of carbon dioxide and less so by oxygen levels.
- Chronically high levels of CO2 (i.e., hypercapnia)
can desensitize the body to CO2 and shift respiratory
drive to rely on oxygen levels.
What is Normal PaO2?
75-100 mmHG
What is Pleural Effusion?
This refers to an excess of pleural fluid in the pleural cavity caused by damage to pleura (e.g., by trauma, infection,
malignancy) or when there is either excessive production
of pleural fluid or the resorption capacity is reduced (e.g., lymphatic obstruction)
What can the pleural space be filled with?
- Hemothorax (blood)
- Empyema (pus)
- Air (Pneumothorax)
Is the pleural space continuous with the airways?
The pleural space is NOT continuous with the airways
With Ventilation, what are the 2 opposing forces?
- Inward pull from the elastic tension of the lung tissue trying to collapse the lung
And
- An outward pull of the thoracic wall trying to expand the lungs
With Ventilations opposing forces (Inward/outward pull), what does this give rise to?
These two opposing forces give rise to a subatmospheric
(negative) pressure within the intrapleural space, termed the intrapleural pressure.
- This intrapleural pressure is normally lower than the intrapulmonary pressure developed during both inspiration and expiration.
- In light of these two pressure differences, a transpulmonary or transmural pressure is developed across the wall of the lung
What does Transmural or Transpulmonary Pressure allow?
This allows changes in lung volume to parallel changes in thoracic excursion during inspiration and expiration
What does the Diaphragm do during contraction?
It flattens and moves downward, increasing the space in the chest cavity and decreasing the pressure inside the chest, allowing air to flow into the lungs
What does the Diaphragm do during relaxation?
On relaxation it moves upward into its dome shape, decreasing
the space in the chest cavity and increasing the pressure,
which helps to push air out of the lungs (exhalation)
What innervates the Diaphragm?
Phrenic Nerve
What can the Functioning of the Diaphragm be affected by?
- Weakness and/or fatigue (e.g., after invasive ventilatory support)
- Hyperinflation
- Paralysis or Hemi-paralysis
- Medical procedure (e.g., surgical pain
Using the pic, in the green, what are the Trachea, Primary bronchus, bronchus, Bronchi, and Bronchioles referred as?
This is the conduting zone
- The volum of air ventilated into these areas are referred to as “Dead Space”
Using the pic, in the blue, what are the Respiratory bronchioles, alveolar ducts, alveolar sacs referred as?
This is the Respiratory Zone, aka the “Acinus”
What is the role of the Bronchial Smooth Muscle?
This is under Autonomic nervous system:
- It increases in parasympathetic outflow that causes bronchoconstriction
- It increases in sympathetic stimulation that causes bronchodilation
With Gas Exchange, What are Type 1 Pneumocytes?
These are thin, flat cells which allow gas exchange between the alveolus and capillaries
With Gas Exchange, What are Type 2 Pneumocytes?
These secrete surfactant to prevent the collapse of the alveolus and to prevent the inner walls from sticking together
With Gas Exchage, is Pulmonary Capillary Pressure High or low?
Pulmonary Capillary Pressure is very low - around 7 mmHG
- This keeps the lungs dry
What is Total Lung Capacity (TLC)?
The volume in the lungs at
maximal inflation, the sum of VC and RV
What is Tidal Volume (TV)?
That volume of air
moved into or out of the lungs during quiet breathing
What is Residual Volume (RV)?
The volume of air remaining in
the lungs after a maximal exhalation
What is Vital Capacity (VC)?
The volume of air breathed out after the deepest inhalation. Also called “Forced” Vital Capacity during Pulmonary Function Testing.
What is Forced Expiratory Volume in 1 Seconds (FEV1)?
Volume of air that is exhaled during the 1st second of
the FVC and reflects airflow of the large airways
What is Compliance?
This refers to the ease with which the lungs can expand during inhalation
Some diseases change the lung’s compliance which negatively affects respiratory mechanics and gas exchange
How can compliance be quantified?
It can be quantified by how much the volume of the lungs changes in response to a change in the pressure applied to thenm (i.e., by the respiratory muscles
What is Compliance influenced by?
By elastin and collagen fibers in the alveolar walls and the surrounding blood vessels and bronchi
What is Ventilation-Perfusion (V/Q) Matching?
This describes the relationship between the amount of air reaching the alveoli (ventilation) and the amount of blood passing by the alveoli in the pulmonary capillaries (perfusion)
What happens if there are disruptions in V/Q matching?
This can lead to inadequate oxygenation of the blood or ineffective elimination of carbon dioxide and are central to many pulmonary diseases and conditions affecting respiratory function
What is the Difference between Shunt and Dead Space?
- Shunt is when blood bypasses the alveoli without gas exchange
- Dead Space is when the areas of the lungs are ventilated but not perfused with blood
Why is patient positioning important to those with respiratory problems?
A patients position can help a optimize gas exchange in the lungs
Why would Gravity-Assisted Positioning be beneficialto patients with respiratory problems?
By using gravity-assisted positioning, we can optimize perfusion and ventilation to these areas. For instance, a “good lung down” position can be beneficial in unilateral lung diseases. By placing the less affected lung down, it receives more perfusion due to gravity, matching the relatively normal ventilation, thereby improving the overall V/Q ratio
Why would Upright positions be beneficial to patients with respiratory problems?
These positions can be beneficial, especially in patients with conditions like COPD by improving diaphragmatic movement and reducing the work of breathing. Upright positioning can enhance ventilation to the lung bases, improving the V/Q match in these areas, which are more heavily perfused due to gravity
Why would Prone positions be beneficial to patients with respiratory problems?
This positioning can improve V/Q matching in patients with conditions like ARDS. Prone positioning can redistribute pulmonary blood flow, decrease pleural pressure and lung compression, and mitigate V/Q mismatch, potentially improving oxygenation
Why would Mobility be beneficial to patients with respiratory problems?
Mobilizing the patient as much as possible can also assist
in improving V/Q matching. It promotes lung expansion, secretion clearance, and enhances overall lung function
Why would Postural Drainage Positions be beneficial to patients with respiratory problems?
These positions can help mobilize secretions from specific lobes or segments of the lungs, enhancing ventilation to these areas and consequently improving V/Q matching. For example, in patients with bronchiectasis or cystic fibrosis where mucus accumulation is a significant issue, postural drainage positions can facilitate mucus clearance, improve ventilation, and thus enhance V/Q matching.
What is Bronchospasm? What are some causes of this?
This is constriction of the muscles of the walls of the bronchioles
Causes:
- Asthma
- COPD
- Allergens or other environmental irritants
- Exercise-induced brochospasm
- Cold Temp.
- Infections
What are the Cardinal Signs of Bronchospasm?
The cardinal signs of bronchospasm include wheezing, a high-pitched whistling sound during exhalation, and dyspnea. Individuals often experience chest tightness and persistent coughing as reflex responses to airway irritation. Visible use of accessory muscles and prolonged expiration reflect the increased effort to breathe due to narrowed airways
What is Pulmonary Consolidation?
A region of normally compressible lung tissue that has filled with liquid instead of air. Consolidation occurs through accumulation of infiltrates in the alveoli and adjoining ducts which can be made up of:
- white blood cells (e.g., pus)
- inhaled fluid (e.g., water)
- blood (from bronchial tree or hemorrhage from a pulmonary artery)
What is Pulmonary Effusion?
Fluid in the pleural space, caused by various conditions including heart failure and infections, presenting with fluid collections at the lung bases and symptoms like dyspnea
and pleuritic chest pain
What is Pulmonary Edema?
Fluid within the alveoli and interstitium (spaces between the alveoli and the capillaries), often due to heart failure (cardiogenic), where increased pressure in the pulmonary capillaries causes fluid to leak out. Non-cardiogenic causes include acute respiratory distress syndrome (ARDS), where increased permeability of the alveolar-capillary barrier allows fluid to enter the alveoli
What is Atelectasis?
A pathological collapse or incomplete expansion of lung tissue, resulting in partial or complete loss of lung volume due to alveolar airspace closure
Atelectasis can also happen when a person takes small, shallow breaths, which can happen due to pain, sedatives, or prolonged bed rest. Over time, this inadequate lung expansion can cause parts of the lung to collapse.
What is Obstructive Atelectasis?
A consequence of blockage of an airway. Air retained distal to the occlusion is resorbed from nonventilated alveoli, causing the affected regions to become totally gasless and then collapse
With Non-obstructive Atelectasis, what is Relaxation (i.e., Passive) Atelectasis?
This ensues when contact between the parietal and visceral pleurae is eliminated (e.g., as within pleural effusion or pneumothorax)
With Non-obstructive Atelectasis, what is Compressive Atelectasis?
This occurs when a space occupying lesion of the thorax (e.g., pleural effusion or solid mass of the chest wall, pleura, or parenchyma) presses on the lung and causes the lung volume to diminish to less than the usual resting volume (i.e., the functional residual capacity)
What is a Respiratory Exam determined by?
Determined by both arterial partial pressure of oxygen (oxemia) and partial pressure of carbon dioxide (-capnia)
How does the body attempt to correct hypoexemia (low levels of O2) and Hypercapnia (High levels of CO2)?
By increasing tidal volume (TV) and respiratory rate (RR). Together, TV (mL/cycle) x RR (cycles/min) = Minute Ventilation (mL / min)
With a respiratory exam, what is the normal repsonse to activity?
Hyperpnea (increased depth of breathing) followed by increases to RR
What are breathing patterns mostly influenced by?
- Chemoreceptor activity (peripheral and central) sensing alterations in blood pH, CO2, and oxygen levels
- Hypothalamic and Limbic Input (e.g., fear, anxiety)
- Acute or chronic changes to anatomy (e.g., trauma, hyperinflation, kyphosis, scoliosis)
- Disruptions in the neurogenic control of the respiratory pump (e.g., as seen in comatose patients)
How can respiration be assessed by?
Via visual inspection, palpation and/or with tape measure
What is Tachypnea?
> 20 cycles/min
- Poor specificity but usually suggests moderate-to-severe cardiorespiratory disease that is triggering a compensatory increase in ventilation effort/work of breathing
- Has better sensitivity such that its absence challenges the differential diagnosis of significant
cardiorespiratory dysfunction
What are the causes of Bradypnea?
Hypothyroidism, CNS or ANS dysfunction, narcotics/sedatives
What is Apnea? What are the causes?
This is the cessation of breathing
Caused:
- Drug-induced
- CNS dysfunction
- obstructive sleep apnea
What is the Difference between Hyperventilation vs Hypoventilation?
- Hyperventilation: Increased rate and/or depth of ventilation where the body eliminates more carbon dioxide than is being
produced. Common causes:
-Metabolic Acidosis w/ Kussmaul’s breathing:
-Anxiety, Fear - Hypoventilation: Decreased rate and/or depth of breathing which leads to increased concentration of CO2 and eventual hypoxia
-Sedation, somnolence, neurologic depression of respiratory centers, metabolic alkalosis
