Lung disorders Flashcards
What term describes the maximum amount of air that can be exhaled after a maximum inhalation?
vital capacity
Define the volume of air inhaled or exhaled with each breath under resting conditions.
tidal volume
How do you calculate the inspiratory capacity?
Inspiratory capacity is calculated by adding the tidal volume and the inspiratory reserve volume together.
What does functional residual capacity refer to?
Functional residual capacity is the volume of air remaining in the lungs after a normal, passive exhalation.
Explain the significance of the residual volume in the lungs.
Residual volume is important because it prevents lung collapse by maintaining alveolar inflation.
How is vital capacity related to total lung capacity?
Vital capacity is the total amount of air that can be exhaled after a full inhalation and is a portion of the total lung capacity minus the residual volume.
Describe the difference between inspiratory reserve volume and expiratory reserve volume.
Inspiratory reserve volume is the additional air that can be inhaled with effort after a normal inhalation, whereas expiratory reserve volume is the additional air that can be forcibly exhaled after the end of a normal exhalation.
What might an increase in residual volume indicate about lung function?
An increase in residual volume often indicates obstructive lung disease, where the emptying of the lungs is impaired.
How can a spirometry test be useful in diagnosing respiratory conditions?
Spirometry can help measure lung volumes and flow rates, which are essential for diagnosing conditions like asthma, chronic obstructive pulmonary disease (COPD), and restrictive lung disease.
what is coughing?
Coughing is a reflexive action of the body that serves as a protective mechanism for the lungs.
Protective Function: A cough is an explosive expiration that helps protect the lungs from aspiration of foreign materials. It also aids in the movement of secretions from the lower respiratory tract toward the mouth [where it can be swallowed or expectorated].
what triggers innate cough reflex?
mucosa located between the larynx and the second-order bronchi. In some cases, stimulation of other areas, such as the ear canal due to cerumen (ear wax), or inflammation of the pleura (the membrane surrounding the lungs), can also trigger a cough.
what are some common causes of cough?
Etiological Classification of Cough Causes:
Mechanical: Distortion of the airways, which may occur due to conditions like fibrosis (scarring of the lung tissue) or atelectasis (collapse of part of the lung).
Inflammatory: Inflammation of the trachea and bronchi, which can be caused by viral or bacterial infections, or by chronic inflammatory processes affecting the respiratory system.
Chemical: Inhalation of irritants such as smoke or dust can irritate the airways and trigger a cough reflex.
Drugs: Certain medications, particularly angiotensin-converting enzyme (ACE) inhibitors, which are commonly used to treat high blood pressure and heart failure, can cause a dry cough as a side effect.
Psychogenic: A dry cough can sometimes be related to psychological factors such as anxiety. While cough is generally a manifestation of an organic disease, stress and psychological factors can exacerbate a cough that has an organic cause.
which trug tends to cause cough?
ACE inhibitors
what is the process of cough reflex?
Rapid Inspiration:
The process begins with a deep and rapid inhalation, which draws air into the lungs.
Closure of the Glottis:
Following the inhalation, the glottis (the opening between the vocal cords in the larynx) closes abruptly to trap the air within the lungs.
Contraction of Expiratory Muscles:
Almost simultaneously, the muscles of the abdomen and thorax (including the diaphragm and the intercostal muscles) contract forcefully. This contraction increases the pressure inside the thoracic cavity.
Increase in Pressure:
The pressure within the pleural cavity (the thin fluid-filled space between the two pulmonary pleurae of each lung) and the lungs themselves (intrapulmonary pressure) rises sharply. This pressure can reach levels significantly higher than normal, often between 100 to 200 millimeters of mercury (mmHg).
Sudden Opening of the Glottis:
After a brief moment, the glottis opens suddenly, allowing the pressurized air in the lungs to be expelled rapidly.
Expulsion of Air:
A burst of air rushes out of the lungs, through the open glottis, and out of the mouth at high speed. This fast-moving air helps to dislodge and expel any irritant or foreign material from the airways.
what does the pressure in the pleural cavity and lungs increase to during cough reflex?
This pressure can reach levels significantly higher than normal, often between 100 to 200 millimeters of mercury (mmHg).
which part of the trachea invaginates and narrows the trachea during cough reflex and why?
the posterior non-cartilaginous part
The trachea has cartilaginous rings that provide structural support to prevent collapse. However, the posterior part of the trachea (the membranous part) does not have cartilage and is therefore more flexible. The high pressure generated during the cough can cause this part of the trachea to invaginate or fold inwards, narrowing the trachea’s lumen.
The combination of high pressure and high-velocity airflow acts to do what during cough reflex?
dislodge and propel the material up the trachea and into the throat, from where it can be swallowed or expectorated.
what is Bernoulli principle?
the principle of fluid dynamics (Bernoulli’s principle), when the velocity of a fluid (in this case, air) increases, its pressure decreases.
where are the irritant receptors primarily located that contributes to cough reflex?
These receptors are primarily found in the larynx, trachea, and large bronchi but can also be present in the external auditory meatus (ear canal), diaphragm, pleura, and stomach.
once irritant receptors are activated what do they send afferent sensory signals through to the cough center in the brain?
vagus nerve CNX
where is the cough center located in brain that integrates signal inputs?
medulla oblongata
The cough center integrates the incoming signals and if the stimulus is sufficient, it triggers an efferent (motor) response. This center can also be influenced by higher brain functions, such as emotions and conscious control, which is why sometimes a cough can be voluntarily suppressed or exacerbated.
why are we able to voluntarily suppress or exacerbate our cough?
This cough center can also be influenced by higher brain functions, such as emotions and conscious control, which is why sometimes a cough can be voluntarily suppressed or exacerbated.
the efferent signals are sent out from the cough centers through which nerves?
The efferent signals are sent out from the cough center through the vagus, phrenic, and spinal motor nerves to the effector organs.
The efferent signals lead to a coordinated series of muscular actions: the glottis closes, the muscles of the chest wall, diaphragm, and abdomen contract to generate increased intra-thoracic pressure, and then the glottis suddenly opens, resulting in a rapid expulsion of air from the lungs. This high-speed air flow is what helps clear irritants from the airways.
what structure that’s part of the innate defense mechanism of the respiratory tract moves the mucus up towards the pharynx to be swallowed or expectorated?
mucociliary escalator
What are some common symptoms associated with upper respiratory tract infections like sinusitis or nasopharyngitis?
Upper respiratory tract infections can lead to symptoms such as a sensation of needing to clear the throat, postnasal drip, and following an upper respiratory syndrome or sinus symptoms.
How does tracheobronchitis typically present itself symptomatically?
Tracheobronchitis is associated with a sore throat, running nose, and eye irritation.
What differentiates bronchopneumonia from acute bronchitis?
Bronchopneumonia, which is usually dry or productive, begins as acute bronchitis but can become purulent, indicating an infection.
In the context of respiratory illnesses, what characterizes the exacerbation of chronic bronchitis?
An exacerbation of chronic bronchitis is indicated by the production of mucoid sputum becoming purulent.
How is chronic bronchitis defined in terms of duration and sputum production?
Chronic bronchitis is defined by the production of sputum on most days for more than three consecutive months in a year, for more than two years.
What are some distinct features of tuberculosis or fungal respiratory infections?
Tuberculosis or fungal respiratory infections are persistent for weeks to months, often with blood-tinged sputum.
Describe the nature of the cough associated with interstitial fibrosis and infiltrations.
Interstitial fibrosis and infiltrations usually cause a nonproductive, persistent cough, which depends on the origin of the condition.
How might adenocarcinoma in situ or minimally invasive lung cancer affect sputum production?
Adenocarcinoma in situ or minimally invasive lung cancer typically presents similarly to bronchogenic carcinoma, with occasional instances of large quantities of watery, mucoid sputum.
What symptom is often associated with mediastinal tumors due to their location?
Mediastinal tumors often cause breathlessness due to compression of the trachea and bronchi.
What cough symptom can be indicative of a foreign body in the airway?
A foreign body in the airway can cause a cough with immediate signs of asphyxiation if still in the upper airway, or a nonproductive, persistent cough with a localizing wheeze if in the lower airway.
How can left ventricular failure affect cough, especially when lying down?
Left ventricular failure can intensify coughing while lying supine, along with the aggravation of dyspnea.
what is the hallmark sign of croup?
A loud metallic barking cough
what is croup?
an infection that leads to swelling around the vocal cords (larynx), windpipe (trachea), and bronchial tubes (bronchi).
what are some causes for the loud barking cough heard in croup?
Subglottic Edema: The term “subglottic” refers to the area just below the vocal cords. When this region becomes swollen due to inflammation, it narrows the airway.
Non-Productive Cough: The cough associated with croup does not typically produce mucus or sputum, hence it’s described as “non-productive.”
‘Metallic’ Quality: The cough is often described as having a metallic sound because the airflow through the narrowed, inflamed subglottic area produces a unique resonating sound.
Occurrence in Children: Croup is most common in children. Their airways are smaller and more susceptible to becoming obstructed when swelling occurs.
Acute Bacterial or Viral Laryngotracheitis: Croup can be caused by a viral infection (most commonly the parainfluenza virus) or, less frequently, by a bacterial infection. Laryngotracheitis refers to inflammation of the larynx and trachea.
Inspiratory Stridor: This is a high-pitched, wheezing sound made when a child breathes in. It is another indication of the narrowed airway and is often more noticeable when the child is crying or agitated.
Respiratory Distress: The child may show signs of difficulty breathing, such as fast breathing, the use of accessory muscles (neck, chest, and abdominal muscles), and retractions (skin pulling in around the ribs with each breath).
what are signs of respiratory distress in a child with croup?
The child may show signs of difficulty breathing, such as fast breathing, the use of accessory muscles (neck, chest, and abdominal muscles), and retractions (skin pulling in around the ribs with each breath).
croup is caused more by viral infection than by bacterial infection, which virus is it mainly caused by?
parainfluenza virus
Acute Bacterial or Viral Laryngotracheitis: Croup can be caused by a viral infection (most commonly the parainfluenza virus) or, less frequently, by a bacterial infection. Laryngotracheitis refers to inflammation of the larynx and trachea.
what signs are croup often accompanied with?
inspiratory stridor and respiratory distress
what is inspiratory stridor?
This is a high-pitched, wheezing sound made when a child breathes in. It is another indication of the narrowed airway and is often more noticeable when the child is crying or agitated.
when is inspiratory stridor most noticeable in a child with croup?
agitated or crying
why is croup more common in children?
Croup is most common in children. Their airways are smaller and more susceptible to becoming obstructed when swelling occurs.
what are some things that can impair cough reflex?
Damage to Irritant Receptors: Irritant receptors in the airways can be damaged by conditions like bronchiectasis, which involves chronic inflammation and dilatation of the bronchi. Furthermore, narcotics and anesthetics can reduce the sensitivity of these receptors, making them less responsive to irritants.
Neurological Disease: Diseases that affect the nervous system can damage the neural pathways responsible for the cough reflex, which can include peripheral nerves or centers in the central nervous system (CNS).
Tracheostomy Effects: A tracheostomy, which is a surgical procedure to create an opening in the trachea, bypasses the normal upper airway structures. This eliminates the closure of the glottis, which is crucial for generating the high-pressure gradient needed for an effective cough, thus decreasing peak intrapulmonary pressures.
Respiratory Muscle Weakness: Illness, aging, or neuromuscular diseases can weaken the respiratory muscles. This weakness can prevent the generation of sufficient pressure for an effective cough.
to impair cough reflex, what part must be affected?
Interrupting or blunting any step in the sequence may impair the cough reflex.
what’s the minimum expiratory pressure you must be able to achieve in order to produce peak flow for an effective cough?
> 60 cm of water
An effective cough requires the ability to generate high expiratory pressures. If a patient can achieve expiratory pressures greater than 60 cm H2O, they are typically able to produce a peak flow that will result in an effective cough.
what are 2 conditions that can damage irritant receptors?
bronchiectasis and narcotics/anesthetics
what is equal pressure point (EPP)?
The EPP is a theoretical point in the airways where the pressure inside the airway equals the pressure outside the airway in the surrounding tissue. During a cough, the location of this point is crucial for determining which parts of the airway can effectively clear secretions.
when the lung volume is high, where is the equal pressure point (EPP) located?
the larger airways
When the lung volume is high, the EPP is located in the larger airways. This is because the larger airways are held open by the higher surrounding pressure due to the inflated lungs. A cough at this volume can generate a high-velocity airflow from deep within the lungs, which helps to move secretions from the smaller airways into the larger ones where they can be more easily expelled (“downstream”).
when the lung volume is decreased where is the equal pressure point (EPP) located?
closer to alveoli
As lung volume decreases, such as after several coughs without an intervening breath, the EPP moves “upstream” closer to the alveoli. At lower lung volumes, the airway pressure can fall below the pressure of the surrounding tissue, causing smaller airways to collapse. This collapse can trap secretions in the small airways and alveoli.
why can repeatedly coughing without taking breaths hinder clearance of secretions?
It prevents reinflation of lungs and allows small airway collapse
If a person coughs repeatedly without taking a breath in between, the EPP moves progressively closer to the alveoli with each cough. This is beneficial because it helps clear particles from the deeper parts of the lungs. However, it is also important to have intervening inspirations to re-inflate the lungs and prevent small airway collapse, which can hinder the clearance of secretions.
for cough to be most effective it should occur at what lung volume and where should the EPP be located?
For a cough to be most effective, it should occur at a relatively high lung volume to ensure that the EPP is in the larger airways and to maximize airflow velocity, thereby helping to clear secretions from the lower respiratory tract.
what are the consequences of increased thoracic pressure in the body for cough?
Rise in Vascular Pressures: The increase in intrathoracic pressure causes a corresponding increase in the pressure within the vessels, including blood vessels and the cerebrospinal fluid (CSF). This pressure change is transmitted evenly and does not typically alter the pressures on the coronary vessels, lungs, or other organs significantly, hence typically there are no direct clinical consequences on these structures from the pressure change alone.
Reflex Vasodilation: The body responds to the rise in intrathoracic pressure with a reflex that causes the systemic arteries and veins to dilate. This reflex vasodilation is likely a compensatory mechanism to maintain adequate cardiac output despite the increased pressure.
Decrease in Cardiac Output and Venous Return: Vasodilation of the vessels can reduce the amount of blood returning to the heart (venous return), which in turn can decrease cardiac output. Cardiac output is the volume of blood the heart pumps per minute, and it is determined by the stroke volume (the amount of blood pumped with each beat) multiplied by the heart rate.
Potential for Syncope: In patients with cor pulmonale (right-sided heart disease caused by lung disease) and right heart failure, these changes in pressure and cardiac output can be critical. These patients have a compromised ability to compensate for fluctuations in pressure and blood flow. As a result, a significant decrease in cardiac output can lead to syncope (fainting) due to inadequate perfusion of the brain.
why might Vasodilation leads to a decrease in cardiac output and then a decrease in venous return when intrathoracic pressure has increased for cough?
Decrease in Cardiac Output and Venous Return: Vasodilation of the vessels can reduce the amount of blood returning to the heart (venous return), which in turn can decrease cardiac output. Cardiac output is the volume of blood the heart pumps per minute, and it is determined by the stroke volume (the amount of blood pumped with each beat) multiplied by the heart rate.
why might people with cor pulmonale or right heart failure encounter syncope during increased thoracic pressure for cough?
Potential for Syncope: In patients with cor pulmonale (right-sided heart disease caused by lung disease) and right heart failure, these changes in pressure and cardiac output can be critical. These patients have a compromised ability to compensate for fluctuations in pressure and blood flow. As a result, a significant decrease in cardiac output can lead to syncope (fainting) due to inadequate perfusion of the brain.
which gender experience cough syncope more and why?
Men may be more prone to cough syncope because they can typically generate higher intrathoracic pressures compared to women. This greater pressure can lead to a more significant decrease in cardiac output.
what condition does cough syncope resemble and how do you differentiate the 2?
It is crucial to distinguish cough syncope from epileptic seizures, as the two can appear similar. In the past, cough syncope was sometimes considered a form of epilepsy, but they are now recognized as distinct conditions. Epileptic seizures are neurological events caused by abnormal electrical discharges in the brain, while cough syncope is a circulatory issue.
epilepsy need to be ruled out
what is the probable cause of post-tussive cough?
person coughs more forcefully and longer than average person affecting circulatory system.
what are causes of dyspnea?
Dyspnea can be due to issues in the respiratory system such as asthma, COPD, pneumonia, or pulmonary fibrosis. Cardiac conditions like heart failure or myocardial infarction can also cause dyspnea. Other causes include neuromuscular disorders that affect the muscles involved in breathing, psychogenic causes such as anxiety, or systemic illnesses like anemia or metabolic acidosis. Often, these causes can overlap.
what is air hunger?
desperate feeling of being unable to breathe sufficiently, sometimes accompanied by panic.
how do you describe acute dyspnea?
Acute dyspnea develops over a short time, typically hours to days, and is often more alarming to the patient. It may signal an urgent medical condition.
how do you describe chronic dyspnea and what is it usually due to?
Chronic dyspnea persists over a longer period, usually defined as more than 4 to 8 weeks, and can be due to ongoing medical conditions like COPD or chronic heart failure.
what is the pathway of sensation of breathlessness?
Sensory Input: Signals from the body are sent to the brain regarding the state of the airways, lungs, respiratory muscles, and the chest wall. This includes input from mechanoreceptors in the respiratory tract and chemoreceptors that respond to changes in blood gases.
Motor Cortex: Signals for respiratory effort originate here and are sent to the ventilatory muscles.
Brain Stem: This area regulates the automatic aspects of breathing and contributes to the sensation of air hunger, which is the uncomfortable feeling of not getting enough air.
Vagal Stimulation: The vagus nerve, which innervates the lungs, sends signals when irritant receptors are stimulated, contributing to the sensation of chest tightness.
what causes air hunger?
Air Hunger: This perception arises from increased respiratory activity within the brain stem.
what are some respiratory causes of dyspnea?
Respiratory Causes:
Conditions that obstruct air flow (e.g., asthma, COPD).
Infections that impair gas exchange (e.g., pneumonia).
Blockages in the pulmonary blood vessels (e.g., pulmonary embolism).
Diseases affecting lung tissue and its ability to expand (e.g., lung malignancy, pneumothorax).
Inhaled foreign objects causing obstruction (aspiration).
what are some cardiovascular causes of dyspnea?
Cardiovascular Causes:
Heart conditions that prevent proper circulation (e.g., congestive heart failure, valvular heart defects).
Increased pressure in the pulmonary circulation (pulmonary hypertension).
Conditions that affect the heart’s rhythm (cardiac arrhythmia).
Abnormal connections between the heart chambers (intracardiac shunting).
Accumulation of fluid in the lung tissue (pulmonary edema).
Compression of the heart by fluid in the pericardium (pericardial tamponade).
what are some neuromuscular causes of dyspnea?
Neuromuscular Causes:
Physical trauma to the chest wall or spinal injuries.
Diseases affecting the muscles and nerves involved in respiration (myopathy, neuropathy, phrenic nerve paralysis).
Structural deformities that impair lung function (kyphoscoliosis).
Excessive body weight increasing the work of breathing (obesity).
what are some psychogenic causes of dyspnea?
Psychogenic Causes:
Conditions where emotional or psychological factors lead to the sensation of breathlessness (hyperventilation syndrome, psychogenic dyspnea).
Dysfunctions of the vocal cords that can mimic respiratory conditions (vocal cord dysfunction syndrome).
what are some systemic causes of dyspnea?
Systemic Illnesses:
Conditions affecting the body’s oxygen-carrying capacity (anemia).
Metabolic disturbances that can lead to increased breathing rate (metabolic acidosis).
Endocrine disorders that accelerate metabolism (thyrotoxicosis).
Severe allergic reactions or infections causing systemic responses (anaphylaxis, sepsis).
Swelling in the airways (angioedema) or inflammation of the epiglottis (epiglottitis).
What are two acute conditions that can cause dyspnea due to a rapid accumulation of fluid in the lungs?
Acute pulmonary edema and adult respiratory distress syndrome (ARDS) can both cause rapid fluid accumulation in the lungs, leading to acute dyspnea.
Name a chronic condition that can progressively lead to dyspnea by causing obstruction of the airways.
Chronic obstructive pulmonary disease (COPD) is a chronic condition that can cause airway obstruction and progressive dyspnea.
Which acute event can cause dyspnea by disrupting the integrity of the lung’s pleural space?
A spontaneous pneumothorax, which is the sudden presence of air in the pleural space, can disrupt normal lung function and cause acute dyspnea.
How can a condition affecting the heart lead to chronic symptoms of dyspnea?
Left ventricular failure can lead to chronic dyspnea due to the back-up of fluid into the lungs, a condition known as congestive heart failure.
What is a potential psychogenic cause of dyspnea and how does it manifest?
Psychogenic dyspnea, which is often related to anxiety, can manifest as a sensation of breathlessness or suffocation without an organic cause.
Identify a blood condition that can cause chronic dyspnea and explain why it affects breathing.
Severe anemia can lead to chronic dyspnea because the reduced number of red blood cells limits oxygen transport to tissues, prompting increased breathing to meet oxygen demands.
which condition that can cause dyspnea can be considered as both acute and chronic?
asthma
what is it called when there is a mismatch between the effort of breathing and the actual movement of air, perceived by the respiratory center in the brainstem. Essentially, the brain registers that despite efforts to breathe, not enough air movement (effective ventilation) is occurring?
Respiratory System Neuromechanical Dissociation
what is it called when Dyspnea arise when the efferent (motor) neurological signals that regulate tidal volume (the amount of air moved into and out of the lungs with each breath) and respiratory rate do not achieve the expected mechanical results. This discrepancy is sensed through feedback from airflow and chest expansion and can cause the sensation of breathlessness?
Efferent Neurologic Output Failure
what can lead to extreme dyspnea?
When the neuromechanical dissociation is combined with a strong ventilatory stimulus such as hypercarbia (high carbon dioxide levels in the blood), metabolic acidosis, or hypoxemia (low blood oxygen levels), it can lead to extreme dyspnea.
how do you calculate vital capacity?
Vital Capacity (VC): The maximum amount of air that can be exhaled after a maximum inhalation. VC can be calculated by adding the ERV, VT, and IRV.
