NR 507 Pulmonary System & Function

Flattented Diaphragm Rationale: In COPD, there is hyperinflation of the lung that results in an expanded chest. This leads to a flattening of the diaphragm on chest x-ray.

An expected chest x-ray finding for a patient with COPD is a

This statement is false. Non-productive would be true.

An objective finding in a patient with ILD include productive cough.

Hypoxemia and Hypercapnia. Rationale Hypoxemia and hypercapnia are classic late effects of emphysema; hypoxemia occurs because the loss of alveolar surface area available to exchange CO2 and oxygen. Hypercapnia results due to poor oxygenation and also the inability to exhale CO2.

Which of the following is considered a late effect of emphysema?

Decreased FEV1/FVC ratio. Rationale: Chronic bronchitis causes lung hyperinflation that leads to a decrease in the ability to fully exhalate.

Which of the following pulmonary function test results are expected in a patient with chronic bronchitis?

B. FEV1, FVC, and total lung capacity reduced; FEV1/FVC ratio normal.

Which of the following spirometry results indicate restrictive lung disease? A. FEV1, FEV, and total lung capacity normal: FEV1/FVC ratio normal. B. FEV1, FVC, and total lung capacity reduced; FEV1/FVC ratio normal. C. FEV1 reduced, FVC normal, total lung capacity reduced; FEV1/FVC ratio normal. D. FEV1, FEV, and total lung capacity reduced; FEV1/FVC ratio reduced.

Chronic asthma. Rationale: Chronic asthma is an obstructive disease. Pulmonary hypertension and pulmonary fibrosis are restrictive diseases.

Which of the following would indicate obstructive lung disease?

Asthma Characteristics: Mild Persistent

Day Symptoms: 2-6 days/week Night Symptoms: 3-4 days/month Activity Level: Minor limitations Severe Exacerbation: 2/year FEV1: >80% FEV1/FEV: Normal

Asthma Characteristics: Intermittent

Day Symptoms: <2 days/week Night Symptoms: <2 day/month Activity: Level Normal Severe Exacerbation: 0-1/year FEV1: >80% FEV1/FEV: Normal

Asthma Characteristics: Moderate Persistent

Day Symptoms: Daily Night Symptoms: >1 night/week Activity Level: Some limitations Severe Exacerbation: 2/year FEV1: 60-80% FEV1/FEV: Decreased by 5% of normal

Asthma Characteristics: Severe Persistent

Day Symptoms: Throughout the day Night Symptoms: Every night Activity Level: Severe limitations Severe Exacerbation: 2/year FEV1: <60% FEV1/FEV: Decreased by 5% of normal

Asthma results in:

Decreased alveolar ventilation. R: Due to the obstructive nature of asthma, the lungs are unable to properly ventilate.

Asthma results in:

Decreased alveolar ventilation. Rationale: Due to the obstructive nature of asthma, the lungs are unable to properly ventilate.

Which of the following pulmonary function test results are consistent with asthma?

Decreased total lung capacity and residual volume.

Assessment and Diagnosis of ILD

Diagnosis of ILD Diagnosis of ILD is made based on exposure history which includes the patient's current and past occupations as well as hobbies. Ask about exposure to animals, especially birds; medication history, including the use of illicit drugs (methamphetamines, marijuana, smoking crack cocaine and ask about any prior radiation treatment. A chest-x-ray will reveal a honey-comb pattern. There are 4 key tests to definitively diagnose ILD: 1. High resolution chest computed tomography 2. Pulmonary function tests (normal or slightly low FEV1, low FVC, normal or elevated FEV1/FVC ratio and reduced lung volumes); these values represent restrictive lung disease 3. Bronchoalveolar lavage 4. Lung biopsy

Clinical Application - Diagnosis

Diagnosis: Intermittent Asthma For this patient we can see that there is an increased activity of the airway due to some type of stimuli. Asthma is typically induced by triggers that are either 1) physiologic or pharmacologic mediators of asthmatic upper airway response; 2) allergens that cause airway inflammation and reactivity in individuals who are sensitive to them and 3) outside agents or stimuli that produce airway over-responsiveness. In our patient, the fact that she reports seasonal symptoms, her asthma is most likely due to an allergen. Exposure to her roommate's cat might explain why her symptoms have worsened in the last few months. The NP discusses potential triggers for the patient's asthma that include occasional smoking and exposure to pet dander. She encourages the patient to stop smoking and limit exposure to the cat. The NP also underscores the need for the patient to participate in managing her asthma through using the peak flow meter (PEF). Using the patient's height and weight, her 100% lung function is determined, and green, yellow and red zones determined. For medication, the patient is ordered on a Short-Acting Beta-2 agonist to be used as needed to control asthma symptoms. A formal asthma management plan is developed for the patient that includes how to recognize exacerbated asthma symptoms, initiate treatment and monitor its effects using the peak flow meter.

Choose the drugs that are commonly associated with development of a medication-induced interstitial lung disease (ILD):

Drugs that are commonly associated with development of a medication-induced interstitial lung disease (ILD): Methotrexate Amiodarone Nitrofurantoin

Asthma: Flow Volume Loop

During spirometry, a flow volume loop is produced. In expiration, there is a scooping nature to the flow volume loop. An obstruction can be confirmed by noting that the FEV1/FVC is < 70. After albuterol, as shown in the diagram below, the lungs open allowing more airflow. This indicates a normal flow volume loop. Note that there is no scooping pattern with the blue line. This indicates reversible airflow obstruction because of measured improvement after the bronchodilator was administered (albuterol). It is also diagnostic of asthma in the presence of respiratory symptoms mentioned above.

Steps to Analyze Pulmonary Function Tests (PFTs)

First, the NP must understand how the results of the PFT is delivered. The results will yield measured values and percentages of predicted values. Predicted values and lower limits of normal have been standardized by population studies using individuals without lung disease. Each patient's predicted values depend on the age, height, and gender. This information is entered into a computer prior to the PFT. Once the results have been received, the NP looks at two factors: 1) the pattern of the condition; 2) severity of the condition.

The NP is examining a patient with a longstanding history of chronic bronchitis. Cor pulmonale is expected in the patient that presents with:

Hepatomegaly Rationale: Cor pulmonale causes fluid to back up into the body organs from the right side of the heart causing an enlarged spleen.

Extrinsic asthma develops from a predisposition for chronic allergies. Inhaled irritants are typically expelled from the respiratory tract either through the exhalation process or through coughing. Any foreign material remaining in the airway can be absorbed into mucus which will be eventually removed from the airway. If some type of foreign material or antigen can invade through the epithelial layer down into the lamina propria area, it will meet up with the second line of defense, the white blood cell immune inflammatory response. This area is loaded with a number of phagocytic white blood cells which will attempt to engulf and destroy any type of invading antigen or foreign material.

However, in the case of somebody who develops an allergy to an antigen, when that substance enters the lamina propria, instead of simply phagocytizing and destroying the antigen, the immune system overreacts to produce an excessive amounts of immune components. Particularly prominent is the production of excess amounts of IgE. IgE is one of the 5 types of antibodies that we normally produce in an adaptative immune response. However, in the case of an allergic response, that individual produces an excess amount of IgE. IgE typically binds to mast cells that triggers mast cell degranulation which releases chemical mediators including histamine, prostaglandins, leukotrienes, and interleukin. Collectively, these chemical mediators cause smooth muscle constriction, mucus secretion and vasodilation. The vasodilation specifically results in mucosal edema and the migration of even more WBCs to the site. Dendritic cells capture the antigen and present it to a special type of lymphocytes, the TH2 cells. Upon presentation of the antigen to the TH2 cell, these cells, in turn, release large amounts of interleukin. Interleukin stimulates B-cells to produce even more IgE to coat mast cells, which facilitates even more antigen binding and even more degranulation. The interleukins go on to activate the eosinophils, which then release chemicals designed to rid the area of the antigen. But in the case of a hypersensitivity or eventually an asthmatic experience, these excess chemicals not only destroy the antigen, but also damages the surrounding tissue. There will also be an enhanced activation of neutrophils that further amplify this damaging effect. And at some point, the transition is made from an allergic response to a type of response that leads to long term damage and permanent airway remodeling resulting in extrinsic asthma. This causes mucus plug formation which can block the alveolar passageways, leading to air-trapping and hyperinflation. Mast cell degranulation triggered by the excessive amounts of IGE that have formed that will bind the allergen as it enters the airway. Mast cell degranulation releases chemicals that causes mucus production and accumulation as well as chemicals that contribute to smooth muscle constriction. Smooth muscle constriction, along with mucus plugs that form. result in hyperinflation of the alveoli and eventual erosion of airway tissue.

air trapping Rationale: Hyperresonance is the characteristic lung percussion finding when the chest hyperinflated in COPD.

Hyperresonance found on lung percussion with a patient with COPD is primarily due to

Clinical Manifestations: Chronic Bronchitis

Productive cough: Classic sign Dyspnea: Late in course Wheezing: Intermittent History of Smoking: Common Barrel Chest: Occasional Prolonged Expiration: Always present Cyanosis: Common Chronic Hypoventilation: Common Polycythemia: Common Cor Pulmonale: Common

Clinical Manifestations: Emphysema

Productive cough: Late in course with infection Dyspnea: Common Wheezing: Minimal History of Smoking: Common Barrel Chest: Classic Prolonged Expiration: Always present Cyanosis: Uncommon Chronic Hypoventilation: Late in course Polycythemia: Late in course Cor Pulmonale: Late in course

Symptoms common to both intrinsic and extrinsic asthma include:

Wheezing.

Extrinsic asthma is

triggered by an allergic reaction

*Associated with smokers **Are the most common diagnosed

*Associated with smokers Pulmonary Langerhans cell histiocytosis* **Are the most common diagnosed Hypersensitivity Pneumonitis** Pneumoconioses** Radiation pneumonitis** Idiopathic pulmonary fibrosis** Sarcoidosis**

Obstructive Disorder Key Points

-Are characterized by a reduction in airflow. -Result in shortness of breath when exhaling air. -Causes air "trapping" in lungs after full expiration. -Include chronic obstructive pulmonary disorders (COPD) and asthma. -In persons with asthma are usually fully reversible, whereas defects in persons with COPD typically are not.

Restrictive disorders Key Points:

-Are characterized by a reduction in lung volume. -Result in difficulty in taking air into the lungs. -Due to stiffness in lung compliance or chest wall structural abnormality. -Include interstitial lung disease (ILD), scoliosis, neuromuscular causes and significant obesity.

Abbreviations:

-FVC / Forced Vital Capacity -FEV1 / Forced Expiratory Volume in One Second -TLC / Total Lung Capacity -RV / Residual Volume -DLCO / Diffusion Capacity for Carbon Monoxide -BD / Bronchodilator

Intrinsic

-Triggered by a variety of non-allergic factors (chemicals, airborne irritants, infections, exercise, stress, anxiety, GERD, obesity) -No elevation in IgE -More common in adults less than 40 years of age

Extrinsic

-Triggered by an allergic, chronic reaction (pollen, dust mites, pet dander) -Elevated IgE is diagnostic -More common, especially in children

Exposure-related ILD includes the following: *Associated with smokers **Are the most common diagnosed

1. Hypersensitivity pneumonitis** (extrinsic allergic alveolitis) is -caused by an immune-mediated response to inhaled organic dust -there are many subtypes of extrinsic allergic alveolitis depending on the type of substance inhaled -named after the associated occupation or hobby rather than the organism that caused it (e.g., "farmer's lung" is caused by exposure to hay) 2. Pneumoconioses** -caused by inhalation of inorganic substances -coal dust, asbestos, silica, and beryllium 3. Radiation pneumonitis** -due to radiation treatment for intrathoracic cancers 4. Medication-induced -Amiodarone -Nitrofurantoin -methotrexate

There are some indications to help the NP to determine when to order PFTs:

1. When signs and symptoms of a respiratory problem require evaluation (cough, dyspnea, cyanosis, wheezing, hypoxemia, hypercapnia, and lung hyperinflation). 2. When disease progression needs to be determined. 3. When monitoring the effectiveness of drug therapy. 4. When monitoring for potential toxic effects of certain drugs.

Increase residual volume. Rationale: The problem with COPD is getting air out of the lung. The air accumulates and increases the amount of residual volume left in the lung after exhalation.

A lung volume measurement that indicates air trapping in a COPD patient is:

Mucus plugs. Rationale: the production of mucus is one of the problems of chronic bronchitis. Due to the amount of mucus produced, mucus plugs can cause the accumulation of secretion that can lead to pneumonia.

A patient with chronic bronchitis is at risk for developing pneumonia due to:

Respiratory acidosis due to inability to exhale CO2 Rationale: Due to the excess mucus production this can cause an obstruction leading to the inability to exhale CO2; this leads to respiratory acidosis.

A patient with chronic bronchitis is most likely to experience:

80% Rationale: The normal range for the FEV1/FVC is 80%.

A patient with normal lungs should be able to exhale ___ of the forced vital capacity within the first second.

Asthma Management: Medication Management

A step system is used in the pharmacological management of the patient. Step-up means that drug dosages are increased and more added, depending on the severity when the patient has symptoms greater than two days of the week and must be severe enough to require a short-acting beta2 agonist (SABA). The therapy can be stepped down when the symptoms have been controlled for three months. The common medications used in the treatment of asthma are: -Short-Acting Beta-2 Agonists (SABA) (albuterol)-it will act on the beta 2 adrenergic receptors to cause bronchodilation. -Inhaled Corticosteroids (ICS) are used to reduce inflammation. Depending on the severity of the asthma attack, low-dose, medium-dose or high-can be used. Other drugs include: Mast-cell stabilizers (cromolyn sodium)-are used in situations where patients have cold or exercise-induced asthma. They Inhibit the release of histamine by the mast cells and inhibit eosinophils. This is an alternative for patients who have allergic rhinitis and atopic dermatitis associated with their asthma Leukotriene Receptor Antagonists (LTRA)-(Montelukast) -It binds onto the receptors and blocks the reaction of leukotrienes to inhibit bronchospasms and mucus production Omalizumab-an anti-IgE antibody that binds onto the IgE antibody in patients with severe allergic asthma. It helps to decrease bronchospasms, decrease vascular permeability, inflammation and mucus production. It is indicated in the severe stage of asthma who have allergies.

False Fine crackles are noted instead of rhonchi.

A subjective finding in interstitial lung disease is rhonchi in the upper posterior airways.

Intrinsic asthma can be triggered by a variety of non-allergic factors, each causing a slightly different variation on the inflammatory process. Chemicals such as aspirin or non-steroidal anti-inflammatory drugs (NSAIDS) have been known to trigger asthma. These chemicals have the undesirable side effect of causing gastrointestinal (GI) irritation. They can also cause respiratory irritation by the same mechanism because ingesting these chemicals causes a shift in production of mucosal protective substances not only in the GI tract, but also in the respiratory tract causing the production of inflammatory substances. Airborne irritants like tobacco smoke and pollution triggers a natural bronchoconstriction to protect the lower airways. If the irritant, though, is inhaled continually, natural bronchoconstriction, coupled with the irritation that these substances promote in the airways contributes to inflammation and asthma symptoms.

Additional factors that can trigger asthma includes viral infections acquired through infancy, particularly Respiratory Syncytial Virus (RSV), and strain C of the human respiratory virus. These viruses are thought to stimulate excessive immune response in children. This creates a permanent imbalance of immune cells, possibly favoring the activation of the TH2 cells to stimulate the excess production of IgE to ultimately promote more mast cell degranulation. Gastroesophageal reflux disease (GERD) is also associated with the development of intrinsic asthma. The vagus nerve controls acid production. When stimulated, the vagus nerve releases acetylcholine, which is part of our parasympathetic response. The acetylcholine released during GERD will not only increase acid production but can also bind to receptors in the respiratory tract and cause bronchial constriction.

In normal gas exchange, which of the following is correct?

After air is breathed in, it diffuses into the pulmonary veins. R: When air is breathed in, oxygen is carried away from the lung to the left side of the heart via the pulmonary vein.

Asthma Characteristics Asthma is a complex obstructive disease. The wide range of environmental triggers for the condition, the variety of inflammatory chemicals released during an exacerbation, and the large number of genes that may play a role in the susceptibility and development of asthma underscores that no two patients may experience the exact same disease progression nor respond the same way to treatment. The typical presentation during the onset of an attack is chest tightness, expiratory wheezing, dyspnea, non-productive cough, prolonged expiration, tachycardia, and tachypnea. In more severe attacks, the patient will use the accessory muscles to breath. Status asthmaticus may result if bronchospasm is not reversed with treatment. In this case, hypoxemia worsens, expiratory flow rates further decrease and ventilation decreases resulting in acidosis. The absence of breath sounds and a PaCO2 greater than 70 mmHg are signs of impending death. The types of asthma are staged as either intermittent or persistent. Persistent is divided into mild, moderate and severe. Staging considers the frequency of day and nighttime symptoms, the impact on activity level, the frequency of severe exacerbations and the FEV1 and FEV1/FEV results. These are summarized in the following table.

All asthma symptoms tend to occur at night or in the early morning hours. This is a key feature in the diagnosis of asthma. Night and early morning symptoms may be a concern. The inability to sleep impacts the individual's quality of life as symptoms of chest tightness, shortness of breath, coughing and wheezing interrupts sleep. More importantly, worsening of nighttime symptoms that could indicate that further management of the asthma is needed. Although the reasons for the worsening of asthma symptoms at night in some individuals is not clearly understood, there are some factors to be considered. First, there may be environmental triggers in the mattress such as dust mites and pet dander that trigger a reaction. Another potential cause may relate to gastric reflux that may aggravate asthma symptoms at night. Sleeping position may also be factor, especially the reclining position that compresses the airways decreasing lung volumes. Post-nasal drip and coughing also contribute to airway irritation. Bronchospasms may occur as a result of airway cooling during the night. Physiologically, cortisol levels are higher during the day, but decrease during the night. Decreased cortisol levels results in an increase in histamine levels that lead to increased mucus production and inflammation. There is also decreased levels of epinephrine and increased vagal tone that contributes to nighttime asthma symptoms.

Asthma Severity: Steps 1-6

All steps: 1. Provide patient education, tips on environmental control and control comorbidities 2. Ensure that all patients have access to quick-relief medications 3. Step up therapy if needed (after assessment of adherence, environmental control and comorbid conditions) 4. Step down therapy if possible (if asthma is well controlled for ≥ 3 months

Asthma: Peak Expiratory Flow Rate

Another method for determining variable obstruction is through the peak expiratory flow rate. It is simple and convenient to use by the patient in the home setting. You will see values ranging from zero up to around 800 that corresponds to liters/minute. A patient's peak expiratory flow can be predicted by using certain online calculators that use the patient's age, height and gender to determine their personal value. The patient is instructed to take the lever down into the neutral or zero position. The patient inhales maximally and then forcefully exhales to completion. The patient will record three of these values for both morning and evening. Over one week, if these values vary by more than 20%, it is consistent with the variability of obstruction (asthma).

Chronic Bronchitis

As air enters via the naso- or oropharynx, it passes into the trachea which branches into the left and right bronchi. It then branches out into smaller passageways, the bronchioles, and then finally into the alveoli where gas exchange occurs. The anatomical composition of these passageways transitions from cartilage to entirely smooth muscle, which is innervated by the autonomic nervous system. Parasympathetic stimulation, which is mediated via the vagal nerve, releases acetylcholine (AcH). AcH binds to cholinergic receptors in the respiratory tract results in bronchial constriction and decreased airflow. Sympathetic stimulation is mediated by systemic release of the neurotransmitter epinephrine which binds to Beta-2 adrenergic receptors in the respiratory tract. It is responsible for bronchial dilation which increases airflow. Normally parasympathetic stimulation dominates to keep our airways physiologically constricted to limit exposure to potentially noxious substances that we might inhale. Any change in the movement of air in and out of the lungs through any of these passageways will affect perfusion and the body's ability to efficiently exchange oxygen and CO2 at the capillary level.

Interstitial Lung Disease (ILD)

As you may recall, in obstructive pulmonary disorders, patients struggle with expiration, or getting the air OUT. Obstructive pulmonary disorders include those conditions that cause air trapping such as COPD and asthma. Cystic fibrosis and bronchiectasis are two other examples in this class of pulmonary disorders.

Assessment and Diagnosis of ILD

Assessment of ILD Subjective and objective findings in patients with ILD include: -Shortness of breath -Non-productive cough -Hypoxia -Fine crackles, especially during exertion ILD should be considered in any patient presenting with subacute or chronic, progressive shortness of breath and/or a non-productive cough, especially if they have a history of: -Occupational or animal exposure, excluding dogs and cats -Connective tissue disease -Chest irradiation -Taking amiodarone, nitrofurantoin, or methotrexate

Choose the types of interstitial lung diseases (ILD) that are commonly associated with smoking:

Associated with smoking: Respiratory bronchiolitis-interstitial lung disease Desquamative interstitial pneumonia Pulmonary Langerhans cell histiocytosis

Asthma

Asthma is a chronic (obstructive) disease which is characterized by airway inflammation, bronchial hyperreactivity, and smooth muscle spasm that occurs intermittently and has a reversible obstructive airflow component. Asthma is caused by complex interaction of genetic and environmental factors. As a matter of fact, over 100 different genetic mutations have been implicated as possible links to the development of asthma. Asthma results in excess mucus production and accumulation hypertrophy of bronchial smooth muscle airflow obstruction decreased alveolar ventilation. Asthma can take two forms: Extrinsic and intrinsic. The two are compared below:

Characteristics of Obstructive and Restrictive Lung Disease

Before comparing obstructive and restrictive lung disease, remember that we are keying in on how much air the patient can forcefully expire. FEV1 is the amount of air that the patient can forcefully expire in 1 minute. The normal range is between 80% - 120%. Also keep in mind the FVC, which is the amount of air that the patient can forcefully inspire and expire. The normal range is between 3-5 liters. These values can be altered in obstructive and restrictive pulmonary disease.

Chronic Obstructive Pulmonary Disease (COPD)

COPD consists of chronic bronchitis and emphysema and is characterized by an airflow limitation that is not fully reversible. Risk factors for COPD include smoking whether it is via cigarette, pipe, cigar or second-hand exposure. Airborne irritants may also contribute to the development of COPD such as air pollutants, chemical fumes or dust. Additionally, anything that affects the lung growth during gestation can also contribute to the development of COPD such as smoking, antibiotic use, preterm birth, and air pollution. Finally, the inherited mutation in the alpha-antitrypsin gene in patients who have never smoked, is a genetic cause of COPD. COPD, as its name implies, is an obstructive disorder. COPD patients have difficulty in fully expiring air from the lungs (decreased FVC) due to expiratory airway obstruction caused by mucus, edema, and loss of elastic recoil, which causes the airway to collapse. This results in the ability of the lung to passively expire air. Air trapping causes the chest to hyper-expand which leads to increased work of breathing. As a result, patients will develop hypoventilation and hypercapnia. Bronchoconstriction may also occur due to ongoing inflammation, which may be partially reversible with bronchodilators. Chronic inflammation can lead to systemic effects of weight loss, muscle weakness and increased susceptibility to infection. COPD is diagnosed through history, physical exam and diagnostic testing. On respiratory exam, hyperresonance will be identified due to air-trapping. Pulmonary function tests will show a FEV1/FVC ratio <70% with a decreased FEV1 % predicted. Additionally, bronchodilator challenge will result in no change in the obstructive pattern. Arterial blood gas measurements may reveal hypoxemia with activity or rest as well as hypercapnia due to air trapping and the increased effort required for breathing. Chest x-ray will typically demonstrate a flattened diaphragm, distended lung fields and increased thoracic diameter. A high-resolution CT scan may also be used to diagnose COPD.

COPD Background Info

COPD is a group of common chronic respiratory disorders with progressive tissue degeneration and airway obstruction in the lungs. These conditions can be debilitating. Emphysema, chronic bronchitis and chronic asthma make up this disease. COPD is irreversible and progresses to severe lung damage. COPD can lead to severe hypoxia, respiratory failure or cor pulmonale. Smoking is the leading causative factor for emphysema and chronic bronchitis. COPD -Symptoms: Chronic cough, Shortness of breath, Production of mucus, Dyspnea, Fatigue, Chest discomfort -COPD Causes Smoking, Air pollutants, Genes -Emphysema - alveolar membranes break down -Chronic bronchitis - inflammation and excess mucus -A healthy airway has healthy alveoli, open airway, smooth muscles, and normal bronchial tubes.

The most diagnosed interstitial lung diseases are: Radiation pneumonitis Pneumoconioses Hypersensitivity Pneumonitis

Choose the interstitial lung diseases that are the most diagnosed:

Chronic Bronchitis

Chronic bronchitis is a disease characterized by bronchial inflammation, hypersecretion of mucus, and chronic productive cough that persists for at least 3 consecutive months for at least 2 successive years. It is caused by long-term exposure to environmental irritants, repeated episodes of acute bronchitis (infection) and factors affecting gestational or childhood lung development, such as pre-term birth and/or Respiratory Syncytial Virus (RSV) infection in early infancy. The result of chronic bronchitis is excess mucus production and accumulation, hypertrophy of bronchial smooth muscles, hypertrophy and hyperplasia of bronchial mucus-producing cells, airflow obstruction and decreased alveolar ventilation. The lung damage from chronic bronchitis is irreversible. The most common presenting symptoms of chronic bronchitis are productive and purulent cough, copious sputum production, dyspnea, wheezing, rhonchi, cyanosis of the skin and mucus membranes and peripheral edema. These symptoms impair the lungs' ability to perform adequate ventilation and perfusion. Ventilation is the ability to move air in and out of the lung. It is critical to ensure perfusion. Perfusion is the actual exchange of oxygen and carbon dioxide in the blood stream that occurs via the alveoli and pulmonary capillaries.

Decreased forced expiratory flow (FEV1). Rationale: Chronic bronchitis is an obstructive condition. FEV1 is decreased.

Chronic bronchitis will decrease which of the following parameters?

Restrictive Lung Disorders

Conversely, patients with restrictive lung disorders struggle with inspiration or getting the air IN. Patients with restrictive lung diseases cannot fully fill their lungs because of diseased lung tissue or a physical impediment which prevents full chest expansion. Restrictive lung disorders can be classified as either intrinsic or extrinsic: -Extrinsic causes include conditions where the problem is from a source outside of the pulmonary system which restricts airflow. For example, scoliosis, Myasthenia Gravis, Guillain-Bare', Atrophic Lateral Sclerosis, and obesity are extrinsic causes of restrictive lung disease. -Intrinsic causes of restrictive disorders are due to causes within the lungs or damage to the parenchymal tissue. This class of intrinsic, restrictive lung disorders are known as interstitial lung disease (ILD), or parenchymal disease.

Exposure-Related ILD

Hypersensitivity Pneumonitis** (extrinsic allergic alveolitis): Farmer's lung and others Pneumoconioses** Coal worker's lung Asbestos Silica Beryllium Radiation pneumonitis** Medication Induced ILD: Amiodarone Nitrofurantoin Methotrexate

Types of ILD

ILD is not one specific lung condition. It refers to any disease affecting the pulmonary interstitium and typically "excludes infectious and neoplastic diseases". Most ILDs are characterized by a combination of interstitial inflammation, fibrosis, and scarring around the alveoli sacs. Although there is no universal agreement on the classification ILD, the disease can be grouped into four general categories based on etiology: 1. Exposure-related 2. Connective tissue disease 3. Idiopathic 4. Miscellaneous or "other"

Connective tissue disease

ILD secondary to connective tissue disease are the result of systemic autoimmune conditions, such as: -Systemic sclerosis (the most common cause) -Rheumatoid arthritis -Mixed connective tissue disease -Systemic lupus erythematosus (least likely cause)

Step 1 - Determine the pattern

In order to classify the respiratory issue as either obstructive, restrictive or normal., the NP starts by looking at the FEV1/FVC ratio. Obstructive pattern: If the FEV1/FVC ratio is "less than 70%" or less than the lower limit of normal for the patient. FEV1 also falls to a greater degree than the FVC. Restrictive pattern: If the FEV1/FVC ratio is "greater than 70%" or greater than the lower limit of normal, then the spirometry test is either normal, or a restrictive respiratory abnormality is present. To make this distinction, the NP must look at the TLC. In restrictive disorders, the percent predicted of TLC is <80%, where 80-120% represents a normal range.

There are three important measures on which the NP focuses when reviewing spirometry results: 2.) FEV1

Measure Forced Expiratory Volume in 1 second (FEV1); Normal 80-120% Definition Amount of air forcefully exhaled from the lungs in the first second. Maneuver The patient inhales and forcefully exhales as fast as possible.

Anatomical Changes with Chronic Bronchitis: Chronic Low Oxygen

In response to the chronic low oxygen level of the blood, the kidneys compensate by increasing secretion of erythropoietin, the primary hormone responsible for stimulating red blood cell (RBC) production. As a result of increased RBC production, patients with chronic bronchitis exhibit an elevated hematocrit and can develop secondary polycythemia vera. One might think that an increase in RBC to carry oxygen could be beneficial. That is not the case here. The increased blood volume causes additional strain on the pulmonary and cardiovascular systems. The increased blood volume combined with the vasoconstriction caused by chronic hypoxia leads to pulmonary hypertension. This situation increases the workload of the right ventricle as it tries to pump deoxygenated blood into the lungs. Overtime, this results in cardiac hypertrophy and right-sided heart failure or cor pulmonale. The reduced ejection fraction from the right side of the heart causes blood to back up into the venous system causing venous distention and peripheral edema. To diagnose chronic bronchitis, the NP must collect a through health history. The patient should be asked about chronic exposure to any inhaled irritants. Smoking history should also be obtained. The patient will also report chronic cough and sputum production.

Asthma is a chronic disease characterized by:

Intermittent, reversible airflow obstruction. R: The effects of asthma is intermittent and occurs when the individual comes in contact with the triggering factor. It reverses with treatment.

False ILD does not include infectious and neoplastic lung etiologies.

Interstitial lung disease (ILD) includes infectious and neoplastic lung diseases.

This statement is true. Interstitial lung disease refers to any disease affecting the pulmonary interstitium and typically excludes infectious and neoplastic diseases.

Interstitial lung disease refers to any disease affecting the pulmonary interstitium and typically excludes infectious and neoplastic diseases

Clinical Application - Asthma

Mary Nielson A 25-year-old female reports to the primary care office with complaints of episodic chest tightness and shortness of breath that she has experienced more frequently over the last 3 years. She now reports an "attack" every three months, especially during the spring months. She reports no intolerance to exercise. She does report that her roommate has a cat. She smokes occasionally when she is out with friends. The patient denies any family history of asthma, bronchitis, or other respiratory issues, GERD, or obstructive sleep apnea. She does not take any medications. The NP delves deeper into the patient's history to get a full sense of her respiratory symptoms. The patient indicates that, although her symptoms are occurring more often, she reports that her day and night-time symptoms occur less than 2 days/week. She denies any severe exacerbation of the symptoms over the last year. The NP conducts a physical exam and investigates the patients symptoms. Review both below: VS: afebrile, BP 118/70; HR 78; RR; 18; Ht. 5'5"; Wt. 127 lbs.; BMI: 21.1 HEENT: unremarkable Lungs: symmetrical lung expansion, no use of accessory muscles, mild-end-expiratory wheezing auscultated in right and left upper lobes; lung bases clear bilaterally. Heart: S1 and S2 audible with RRR; no murmur, extra heart sounds and Gallup noted Abdomen: unremarkable Musculoskeletal: unremarkable The NP orders a spirometry. The results were normal as indicated below: Predicted / Actual / Predicted FVC (L): 3.61/ 4.21 /117 FEV1 (L) 3.14/ 3.38/ 108 FEV1/FVC (%) 86 /80/ 93 Despite the patient's normal spirometry reading, the NP still has a high suspicion for asthma because of the patient's history. The NP decides that a provocation test is needed and orders a Methacholine Challenge test. The results revealed a 20% reduction in her FEV1 after inhalation of the methacholine (significant bronchial reactivity) which improved by >12% post-bronchodilator therapy. These results demonstrate a provocable, reversible, obstructive pattern of disease. Following the methacholine challenge test, the patient returned for a follow-up visit, where the NP continued the work-up. During this visit, the NP, once again, considered the pattern of patient symptoms, the normal spirometry results and final results of the methacholine challenge to determine that 1) the patient has asthma and 2) it is intermittent based on the characteristics of her day and night-time symptoms and no effect on her activity level.

His minute respiratory volume is (650 mL/breath)(11 breath/min) = 7,150 mL/min (7.15 L/min). With an anatomic dead space of 185 mL; his alveolar ventilation rate is (650 - 185 mL/breath)(11 breaths/min) = 5.12 L/min.

Math: Consider a man in good health with 650 ML tidal volume and a respiratory rate of 11 breaths/minute. Report his minute respiratory volume in liters per minute. Assuming his anatomic dead space is 185 mL calculate his alveolar ventilation rate in liters per minute.

There are three important measures on which the NP focuses when reviewing spirometry results: 3.) FEV1/FVC ratio

Measure FEV1/FVC ratio Definition Determines if the pattern is obstructive, restrictive or normal Maneuver This is a calculated ratio that represents the proportion of a person's vital capacity that they are able to expire in the first second of forced expiration to the full, forced vital capacity.

There are three important measures on which the NP focuses when reviewing spirometry results: 1.) FVC

Measure Forced Vital Capacity (FVC); Normal 80-120% Definition The FVC measures the volume of air in the lungs that can be exhaled. Maneuver Patient inhales as deep as possible and then exhales as long and as forcefully as possible.

Measurement: Total lung capacity (TLC): Normal range is 80-120% of predicted

Obstructive - >120% (represents hyperinflation) Restrictive - <80%

Measurement: Forced vital capacity (FVC)Forced expiratory volume in 1 second (FEV1): Normal is > 80%

Obstructive - Decreased Restrictive - Decreased

Measurement: FEV1/FVC ratio: Normal is 70% or less than the lower limit of normal for the patient

Obstructive - Less than 70% Restrictive - Normal or > 70%

Measurement: Forced vital capacity (FVC)

Obstructive -Decreased or normal Restrictive- Decreased

Obstructive Disorders

Obstructive disorders are characterized by obstruction to airflow during expiration. This can be related to conditions that increase mucus production leading to mucus plugs as in the case of chronic bronchitis or the loss of surface area of the lung that decreases areas of gas exchange as a result in inflammatory processes that destroys the lung's elastic resulting in decreased recoil. Regardless of the cause of the obstruction, there is an increased work of breathing (WOB), which requires more energy and effort to create airflow. This eventually results in a ventilation-mismatch where not enough CO2 is being expelled and not enough oxygen being brought in for gas exchange. In using emphysema as an example, the defect is destruction of the lung's elastic tissue caused by inflammation after the person has been exposed to smoking and other irritants over a long period of time. The lung is infiltrated with inflammatory cells that release cytokines that contribute to airway damage and mucus production. When elastin is destroyed, the lung loses its recoil ability that is necessary to expel air out. This leads to air trapping and enlarged alveoli that results in increased lung compliance and decreased elasticity. Ultimately, the lungs become overstretched without the ability to recoil. Individuals with an obstructive disorder will have less than 70% on their PFT. Both the FEV1 and FVC will be decreased.

Step 3 Bronchodialator Response

One other aspect of spirometry is that it may be repeated after the patient receives a bronchodilator. If either the FEV1 or the FEV increases by at least 12% and by at least 200 mL from the pre-bronchodilator values, then the patient has had a significant bronchodilator response. The NP must consider the degree of severity of the respiratory abnormality.

Methachloline Challenge Test

One other consideration in diagnosing asthma is those patients who present with normal spirometry, but the NP still suspects asthma because they have symptoms suggestive of asthma. At this point, the NP can order a bronchoprovocation test called the Methacholine Challenge Test. It is considered the gold standard for diagnosing asthma. Methacholine is a substance that directly stimulates airway smooth muscle cells to cause bronchoconstriction. The challenge test is performed in a pulmonary function laboratory. After obtaining a baseline FEV1, methacholine is administered in escalating doses until either the FEV1 drops by 20% or the maximum dose is achieved. A graphic representation of a methacholine challenge is seen below. On the "x" axis is the doses of methacholine challenge. The "y" axis is the predicted FEV1. The value of 100% corresponds to the patient's FEV1. The values are plotted after each dose of methacholine. The curve will progressively drop where it crosses the 80% mark. This is an important value because it is considered the provocation challenge dose that causes as 20% decreased in the FEV1. If this value is less that 8-16 mg/mL, this is positive for bronchial hyperreactivity. Simply, if the patient has asthma, the airway constriction will be very pronounced as it reaches the smaller airways. If the test is negative, asthma can be ruled out. The results will be presented in a flow loop similar to the one below: One last point is that before the methacholine challenge test is ordered, the NP must determine if the patient is receiving any medications that can interfere with the interpretation of the results. Short-acting beta agonists, long-acting beta agonists, and anticholinergics can falsely reveal a normal test result. Other symptoms that can be related to asthma include: Increased respiratory rate: An increased respiratory rate can lead to hypoventilation as the patient cannot maintain the effort to breathe. Accessory muscles will be used to maintain breathing. -Breathlessness: Due to respiratory distress, the patient is unable to speak or can only use brief phrases or words. -Tachycardia: The patient may exhibit tachycardia that is related to the increased respiratory effort. -Pulses paradoxus: this will be seen on inspiration where there is a drop in blood pressure by 12 mmHg when the patient inspires. -Decreased alertness: Decreased mental status is an indicator of hypoxia.

Asthma Management: Patient Education

Providing education is critical for asthma management as it is most important in decreasing mortality. Patients are provided an Asthma Action Plan. The patient receives education on what is a mild, moderate and severe reaction, and depending on where they fit within these categories, they will be provided specific information on its management including how to adjust their drug dosages. The patient is also provided information on how to avoid asthma triggers once they are identified. Finally, how to recognize an exacerbation of symptoms and treat them using the PEF meter is also included.

ILD and Smoking Of the 4 general categories of ILD, the most common in smokers is:

Pulmonary Langerhans cell histiocytosis Respiratory bronchiolitis-interstitial lung disease Desquamative interstitial pneumonia

Mechanics of Respiration: Pulmonary Function Tests

Pulmonary function tests (PFTs) are non-invasive tests that provide information about lung function. PFTs alone cannot differentiate among the causes of respiratory abnormalities. Therefore, the patient's history, physical exam and other diagnostics must be considered when making a diagnosis. The PFT can help the NP determine the patient's respiratory pattern, specifically if the abnormality is due to an obstructive or restrictive problem. Once the pattern is identified, PFTs allow the NP to determine the severity of the disease. This data combined with other patient findings, leads to a diagnosis.

Components of a Pulmonary Function Tests: Residual volume (RV) and Total Lung Capacity (TLC) RV + FVC = TLC

RV is the amount of air that remains in the lungs after a forceful exhalation. RV + FVC = TLC. Note that the RV cannot be measured by spirometry. Other methods are used that require the patient to inhale an inert gas (helium) or sit in an airtight booth where the pressure is measured during breathing. These measurements are also called static lung volumes. The values add to the information obtained from spirometry. If the patient has an obstructive disease, RV and TLC results will be elevated which reveals air trapping and hyperinflation. In restrictive disease, the TLC is needed to confirm true restriction. It can also help in quantifying the degree of restriction.

Restrictive Disorders

Restrictive disorders occur because of a decreased compliance of the lung tissue. Unlike emphysema, as discussed above, there is normal amount of elastin. So, the issue is not related to recoil in the restricted lung. The issue is with compliance, which is decreased in a restrictive disorder. Using pulmonary fibrosis as an example, fibrous or scarred tissue increases the elasticity of the lung, but compliance decreases due to the scarring caused by the fibrosis which prevents the lungs from expanding. With low compliance, the lungs do not ventilate adequately because there is limited air that is able to enter the lung on inhalation. If there is not sufficient air going in, then there cannot be sufficient air going out. Therefore, the FVC will be lower while FEV1 increases.

Misc & Other ILDS

Sarcoidosis** Vasculitis granulomatosis with polyangitis eosinophilic granulomatosis with polyangitis Eosinophilic Pneumonia acute chronic Pulmonary Langerhans cell histiocytosis*

Miscellaneous or other *Associated with smokers **Are the most common diagnosed

Sarcoidosis** Vasculitis Eosinophilic pneumonia (acute and chronic) Pulmonary Langerhans cell histiocytosis*

Step 2 Determine the Severity The American Thoracic Society (ATS) system for grading the severity of pulmonary function test abnormality according to the FEV1 percent predicted, where normal is greater than 80%

Severity & FEV1 % Predicted Mild >70% Moderate 60-70% Moderately Severe 50-60% Severe 35-50% Very Severe <35%

Residual volume.

Simple spirometry can be used to measure any of the following EXCEPT: A. Tidal volume. B. Inspiratory reserve volume. C. Vital capacity. D. Residual volume.

False Rationale: Residual capacity is not part of a simple spirometry test because it cannot be measure since it is not expelled.

Simple spirometry includes a measure of residual capacity.

Components of a Pulmonary Function Tests Spirometry

Spirometry: This measures air movement in and out of the lungs during various respiratory maneuvers. The NP can also determine how much air the patient is breathing in and out and how fast the patient is doing it. Think about the respiratory cycle in terms of lung volume and lung capacities. The capacity is just simply the sum of one of more volumes. There are three important measures on which the NP focuses when reviewing spirometry results:

Asthma Severity The severity of the asthma will be classified before it is treated. The table below depicts the six steps to medication management depending on asthma severity: Intermittent Asthma

Step 1 Preferred: Short-acting B2-agonist

cigarette smoking

The number one cause of chronic bronchitis is

Asthma Severity: Persistent Asthma Steps 2-4 consider subcutaneous allergen immunotherapy for patients with allergic asthma

Step 2 Preferred: Low-dose ICS + LABA or medium-dose ICS Alternative: Cromolyn, LTRA, nedocromil or theophylline Step 3 Preferred: Low-dose ICS + LABA or medium-dose ICS Alternative: Low-dose ICS + LTRA, theophylline or zileuton Step 4 Preferred: Medium-dose ICS + LABA Alternative: Medium-dose ICS + LTRA, theophylline or zileuton Step 5 Preferred: High-dose ICS + LABA Consider: Omalizumab for patients with allergies Step 6 Preferred: High-dose ICS + LABA + OCS Consider: Omalizumab for patients with allergies

COPD Classification: The GOLD Criteria

The Global Initiative for Obstructive Lung Disease (GOLD) Criteria for COPD is used to classify the severity of COPD in patients already diagnosed with COPD by spirometry (FEV₁/FVC <70%) who are at their baseline symptoms and lung function. The GOLD criteria should not be used in patients <18 years of age and should not be used in patients with acute exacerbation. Severity \ FEV1/FVC \ FEV1 % Predicted -Stage 1 - Mild / <.70 / ≥ 80%-100% -Stage 2 - Moderate / <.70 / 50% ≤ FEV1 < 80% -Stage 3 - Severe / <.70 / 30% ≤ FEV1 < 50% -Stage 4 - Very Severe / <.70 / 30% < FEV1 < 50%

Hepatomegaly. Cor pulmonale causes fluid to back up into the body organs from the right side of the heart causing an enlarged spleen.

The NP is examining a patient with a longstanding history of chronic bronchitis. Cor pulmonale is expected in the patient that presents with:

Decreased forced expiratory flow (FEV1). Rationale: Chronic bronchitis is an obstructive disease. Therefore, the patient will have decreased expiratory flow rates. The FEV1 will be decreased. Air trapping is also common in obstructive disease which will cause an increased TLC. A decreased diffusing capacity typically only occurs in emphysema, not chronic bronchitis.

The NP is seeing a patient with chronic bronchitis that needs spirometry on today's visit. What pulmonary function test (PFT) findings are anticipated based on the diagnosis of chronic bronchitis?

Pulmonary fibrosis. A normal FEV1/FVC points to a restrictive disorder. Pulmonary fibrosis is due to a restrictive cause.

The NP notes that a patient's FEV1/FVC ratio is normal. Which of the following conditions is most likely the patient's pulmonary issue?

Chronic asthma. Rationale: The FEV1/FVC ratio is a measure of the percentage of a patient's vital capacity that can be expired in the first second of expiration. A reduced (<70%) FEV1/FVC ratio automatically points to obstructive disease. Asthma is an obstructive disease.

The NP notes that a patient's FEV1/FVC ratio is severely reduced. Which of the following conditions is most likely the patient's pulmonary issue?

Restrictive lung disease. Rationale Since the FEV1, FVC and TLC are all reduced this indicates restrictive disease. A normal FEV1/FVC ratio is also a clue that this is not an obstructive problem.

The NP reviews the results of a patient's pulmonary function tests and notes that the FEV1, FVC, and total lung capacity (TLC) are reduced. The FEV1/FVC ratio is normal. Based on interpretation, this reflects:

Anatomical Changes with Chronic Bronchitis

The anatomical changes associated with chronic bronchitis are: Smooth muscle constriction, bronchial wall inflammation and mucus plugs lead to alveolar hyperinflation. Because of the anatomical changes in the bronchioles associated with chronic irritation, ventilation (includes inhalation and exhalation) is compromised, especially exhalation. Pressure differences during inhalation are high enough to force air into the alveoli. During exhalation, however, the narrowing and collapse of the air passageways causes air to be trapped in the alveoli that results in alveolar hyperinflation leading to an expanded thorax. The inability to fully exhale leads to hypercapnia (CO2 retention) that leads to respiratory acidosis.

This statement is true. The honey-comb pattern is found on chest x-ray of individuals with ILD.

The characteristic finding of on a chest x-ray of an individual with ILD is a honey-comb pattern

Components of a Pulmonary Function Tests: Diffusing capacity

The diffusing capacity is simply how well the lungs are able to exchange gas. Gas exchange is most efficient in a lung that has high surface area because it's easier for the blood to pick up the gas that's being exchange. An example of a condition that decreases the patient's diffusing capacity because of a loss of surface area is emphysema. Conditions that increase the lungs thickness can also decrease diffusing capacity as in the case of pulmonary fibrosis.

Inability to block the effects of proteolysis. Rationale: Alpha-antitrypsin normally blocks the effects of proteolysis that prevents inflammation and lung damage. A deficiency blocks its ability to perform this function.

The effects of an Alpha-antitrypsin 1 deficiency is:

This statement is true. The four key diagnostic tests for interstitial lung disease are pulmonary function tests, high resolution CT scan, bronchoalveolar lavage and lung biopsy.

The four key diagnostic tests for interstitial lung disease are pulmonary function tests, high resolution CT scan, bronchoalveolar lavage and lung biopsy.

Anatomical Changes with Chronic Bronchitis: Gas Exchange

The high concentration of CO2 creates unfavorable conditions for gas exchange. There is decreased oxygen exchange leading to a ventilation/perfusion (V/Q) mismatch: Decreased perfusion of the pulmonary capillaries with oxygenated blood cells results in chronic pulmonary hypoxia and cyanosis. The term "blue bloater" is used to describe a patient with chronic bronchitis, with bloater referring to the expanded thorax that these individuals can develop as a result of alveolar hyperinflation. Poor ventilation leads to decreased perfusion which causes right to left shunting. This is the phenomenon where deoxygenated blood passes from the right ventricle to the left ventricle with adequate perfusion (gas exchange).

Pathogenesis of Chronic Bronchitis

The pathogenesis of chronic bronchitis begins with an exposure to airborne irritant that activate bronchial smooth muscle constriction, mucus secretion and the release of inflammatory mediators (histamine, prostaglandins, leukotrienes, and interleukins) from immune cells located in the lamina propria. These airborne irritants can include air pollution or industrial chemicals and fumes. The most common irritant is cigarette smoke and other tobacco products. Remember that all of these bronchial responses are normal to occasional inhalation of airborne irritants. Smooth muscle constriction is important to limit the passage of the irritant deeper into the respiratory tract. Secretion of mucus and release of inflammatory chemicals are also important to help trap the irritant. At some point, though, there is the transition from a normal, protective respiratory response to a detrimental effect. This occurs with long-term exposure to airborne irritants that promote: 1. Smooth muscle hypertrophy that leads to bronchoconstriction 2. Hypertrophy and hyperplasia of goblet cells that lead to the hypersecretion of mucus 3. Epithelial cell metaplasia that creates non-ciliated squamous cells 4. Migration of more white blood cells (WBC) to the site which leads to inflammation and fibrosis in the bronchial wall 5. Thickening and rigidity of bronchial basement membrane which leads to narrowing of bronchial passageways

Idiopathic *Associated with smokers **Are the most common diagnosed

The pathogenesis of idiopathic interstitial pneumonia is poorly understood, hence the name "idiopathic". Idiopathic interstitial pneumonias include the following: -Idiopathic pulmonary fibrosis** -Non-specific interstitial pneumonia -Cryptogenic organizing pneumonia -Respiratory bronchiolitis-interstitial lung disease* -Desquamative interstitial pneumonia* -Acute interstitial pneumonia

Asthma Severity Management

The patient's asthma management plan should include what to do in case of an asthma exacerbation and how to anticipate the onset of symptoms. The patient should be prompted to perform a PEF when they feel themselves becoming breathless, coughing, wheezing, use of accessory muscles and drowsiness. If the PEF is 50-79% of their best, then 2-6 puffs of a SABA should be taken three times every 20 minutes followed by re-evaluation with another PEF. If the repeat PEF is >80%, it's a good response. The patient should continue the SABA every 3-4 hours for 48 hours and follow-up with the provider for medication adjustment. If the repeat PEF is between 50-79%, this is considered an incomplete response to the medication. The patient should use an oral glucocorticoid and SABA and follow-up with the provider. If the follow-up PEF is <50%, this is a poor response. The patient should take an oral glucocorticoid, SABA and then go to the emergency department (ED). If <50% was obtained on the first PEF, the same steps should be followed.

This statement is true. The symptoms that are common to all types of interstitial lung disease are shortness of breath and non-productive cough.

The symptoms that are common to all types of interstitial lung disease are shortness of breath and non-productive cough.

Diagnosis of Asthma

To confirm a diagnosis of asthma two things are needed. First are compatible respiratory symptoms. The clinician must carefully review and analyze the symptoms as the ones listed below. The three symptoms that will be present during an asthma exacerbation is non-productive cough, wheezing initially heard on end-expiration. As the exacerbation worsens, the wheezing will be heard throughout the expiratory phase and then will be heard during inspiration and expiration. Chest tightness will also be described. The symptoms, however, are not enough to diagnose asthma since they can be seen in other respiratory diseases. What makes these symptoms more likely that it is asthma rather than another respiratory disease is their presence after exposure to a trigger. In addition, there must be a demonstration of variable airflow obstruction to diagnose asthma. Obstruction is determined by spirometry which is defined by an FEV1/FEV of < 70% or less than the lower limit of normal. What differentiates asthma from other obstructive diseases is the fact that it is variable and reversible. There are differences between variable and reversible. Variability refers to the fluctuation of lung function over time where the patient has normal spirometry on occasion or abnormal or obstructive spirometry on another occasion. Reversibility is a key differentiator of asthma as well. It is defined as an FEV1 that improves by 12% and 200 mL after the use of a bronchodilator (albuterol). So, in the presence of compatible respiratory symptoms with variable or reversible obstruction, the asthma diagnosis can be confirmed.

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