ASTHMA Flashcards
What is the antibody associated with asthma
IgE Antibody
General Risk Factors for Asthma
Obesity
Family history
Indoor/Outdoor pollutants
Dust, Spray Paint, Fumes, etc.
Viral Infections
Sinitis, Rhitis (Hay Fever), gastroesophageal reflux (GERD)
Exercise-Induced Asthma
Drugs, Food additives, and food preservatives
Sleep (nocturnal asthma)
Emotional stress
Occupational Risk Factors
triggered through occupational sensitizers
Asthma and Gender Epidemiology
Among young children, asthma is about two times more prevalent in boys than girls
Male children also have a higher incident of asthma in infections
After puberty, however, asthma is more common in girls
Perimenstral asthma
Also known as catamenial asthma
Asthma in relation to your period
Extrinsic Asthma
Also known as allergic or atropic
Extrinsic asthma is an immediate (Type 1) anaphylactic hypersensitive reactive
Extrinsic asthma is family related and usually appears in children and adults younger than 30 years old
Will often disappear after puberty
Because extrinsic asthma is associated with an antigen-antibody indicuded bronchospasm, a immunologic mechanism plays a important role
INTRINSIC ASTHMA
NONALLERGIC/NONATOPIC OR TYPE TWO ASTHMA
An asthma episode cannot be directly linked to a specific antigen or extrinsic factor
Onset usually occurs after the age of 40 years
Anatomical Alterations Due to Asthma
Smooth muscle constriction of bronchial airways (bronchospasm)
Bronchial wall inflammation
Excessive production of thick, whitish, bronchial secretions
Mucus plugging
- Hyperplasia of smooth muscle (remodleing)
- Bronchial reactvity and chronic bronchial inflammation
Hyperinflation of alveoli (air-trapping)
In severe cases, atelectasis caused by mucus plugging
Diagnosis of Asthma-Wheezing
WHEEZING-History of the following
- Cough, worse particularly at night
- Recurrent wheeze
- Recurrent difficultly breathing
- Recurrent chest tightness
Symptoms occur or worsen at night, awakening the patient
Symptoms occur or worsen in a seasonal pattern
The patient also has eczema, hay fever, or a family history of asthma or atopic disease
Symptoms occur or worsen in the presence of triggers
Symptoms respond to appropriate anti-asthma therapy
Patient’s colds “go to the chest” or take more than 10 days to clear up
TESTS USED TO DIAGNOSE ASTHMA
Spirometry
Peak Expiratory Flow
Responsiveness to Metacholine, histamine, mannitol, or exercise challenge
Positive skin test with allergens or measurement of specific IgE in serum
INTERMITTENT ASTHMA
Symptons will occue less than once a week, with brief exacerbations.
Nocturnal symptons are less than twice a month
FEV1 or PEF 80% of predicted
PEF or FEV1 variability < 20%
MILD PERSISTENT ASTHMA
Symptoms more than once a week but less than once a day
Exacerbations may affect activity and sleep
Nocturnal symptoms more than twice a month
FEV1 or PEF 80% of predicted
PEF or FEV1 variability < 20-30%
MODERATE PERSISTENT ASTHMA
Symptoms daily
Exacerbations may affect activity and sleep
Nocturnal symptoms more than once a week
Daily use of inhaled short-acting 2-agonist
FEV1 or PEF 60-80% of predicted
PEF or FEV1 variability > 30%
SEVERE PERSISTENT ASTHMA
Symptoms daily
Frequent nocturnal symptoms
Limitations of physical activities
FEV1 or PEF 60% of predicted
PEF or FEV1 variability > 30%
Vital Signs from an Asthma Exasterbation
Increased
- RR
- HR
- BP
PHYSICAL EXMINATION OF AN ASTHMA EXACERBATION
Use of accessory muscles of inspiration
Use of accessory muscle of expiration
Pursed lip breathing
Substernal intercostal retractions
Increased anteroposterior chest diameter (Barrel chest)
Cyanosis
Cough and sputum production
Pulsus Paradoxus (Decreased blood pressure during inspiration and Increased blood pressure during expiration)
Breathing Assessment in Asthma Exasterbation
Expiratory prolongation (I:E > 1:3)
Decreased tactile and vocal fremitus
Hyper-resonate percussion note
Diminished breath sounds
Diminished heart sounds
Wheezing and rhonchi
Forced Expiration Flow Rate Finding in a Moderate to Severe Asthmatic Episode
Obstructive Lung Pathophysiology
Everything will Decrease
FVC
Decreased
FEV1
Decreased
FEV1/FVC Ratio
Decreased
FEF 25-75%
Decreased
FEF50%
Decreased
FEF200-1200
Decreased
PEFR
Decreased
MVV
Decreased
Forced Expiration Flow Rate Finding in a Moderate to Severe Asthmatic Episode-FVC
Normal is 4.8 L
Decreased
Forced Expiration Flow Rate Finding in a Moderate to Severe Asthmatic Episode-FEV1
FEV1 normal is 4.2 L
Decreased
Forced Expiration Flow Rate Finding in a Moderate to Severe Asthmatic Episode-FEV1/FVC Ratio
FEV1/FVC Ratio normal is > or equal to 70%
Decreased
Forced Expiration Flow Rate Finding in a Moderate to Severe Asthmatic Episode-FEF 25-75%
FEF 25-75% is 4.5 L/sec
Decreased
Moderate to Severe Asthmatic Episode-FEF50%
FEF50% normal is 6.5 L/sec
Decreased
Moderate to Severe Asthmatic Episode-FEF200-1200
FEF200-1200 normal is 8.5 L/sec
Decreased
Moderate to Severe Asthmatic Episode-PEFR
PEFR normal is 9.5 L/sec
Decreased
Moderate to Severe Asthmatic Episode-MVV
MVV normal is 160 L/min
Decreased
Moderate to Severe Asthmatic Episode-Vt
Normal or increased
Moderate to Severe Asthmatic Episode-IRV
IRV
Normal or decreased
Moderate to Severe Asthmatic Episode-ERV
Normal or decreased
Moderate to Severe Asthmatic Episode-RV
Increased
Moderate to Severe Asthmatic Episode-VC
Decreased
Moderate to Severe Asthmatic Episode-IC
Normal or decreased
Moderate to Severe Asthmatic Episode-FRC
Increased
Moderate to Severe Asthmatic Episode-TLC
Normal or increase
Moderate to Severe Asthmatic Episode-RV/TLC Ratio
Normal or increased
Arterial Blood Gases in Asthma
An ABG will initially show acute alveolar hyperinflation with hypoxemia, but may show hypercarbia in status asthmaticus
What will the arterial blood gas show in a mild to severe asthma attack
Acute Alveolar Hyperventilation with Hypoxemia (Acute Respiratory Alkalosis)
The PaCO2 will sharply go up and PaO2 will sharply go down because the muscles become over fatigues and can no longer compensate so they hypoventilate
Chest Radiograph
Increased antero-posterior diameter (barrel chest)
Translucent (dark) lung fields
Depressed or flattened diaphragms
Sputum Examination
Eosinophils
Charcot-Leyden Crystals: Product of the breakdown of eosinophils combined with lysophospholipase
Cast of muscus from small airways (Kirschman spirals)
IgE Levels-Elevated in extrinsic asthma
Moderate to Severe Asthma Attack Qs-Qt
This is the shunt %
Normal is <10
In asthma moderate to severe stages will increases
Moderate to Severe Asthma Attack DO2
This is the delivery of O2
Normal is 1000 mL
In asthma moderate to severe stages will decrease
Moderate to Severe Asthma Attack VO2
This is the O2 consumption
Normal is 250 mL/min
In asthma moderate to severe stages will be normal
Moderate to Severe Asthma Attack C(a-v)O2
This is the Content A-V delta
Normal is 5 vol%
In asthma moderate to severe stages is normal
Moderate to Severe Asthma Attack O2ER
This is the extraction ratio
Normal is 25%
In asthma moderate to severe stages will increases
Moderate to Severe Asthma Attack SvO2
This is the venous saturation
Normal is 75%
In asthma moderate to severe stages will decrease
GINA’S FIVE COMPONENETS OF ASTHMA CARE
Identify and Reduce Exposure to Risk Factors
Assess, treat, and monitor asthma
Manage Asthma Exacerbations
Special Considerations
Treatment Protocols
DEVELOP THE PATIENT/DOCTOR PARTNERSHIP
Avoid risk factors
Take medications correctly
Understand the difference between “controller medications” and “reliever” medications (also called rescue medications)
Monitor the status using symptoms and, if relevant, PEFR
Recognize signs that asthma is worsening and take action
Seek medical help as appropriate
Look at your asthma action plan and for indications if status if getting worse
Asthma Management Continuum
From controlls to uncontrolled
- Confirm Diagnosis
- Enviromental control, education, and action plan
- Fast acting bronchodilator on demand
- Inhaled Corticosteroid (ICS)-2nd Line Leukotriene Recptor Anatagonist (LTRA)
- Add LABA if older than 12 but if 6-11 increase ICS
- Add LTRA if older than 12 but if 6-11 add LABA or LTRA
- Anti IgE
- Prednisone
Asthma Exacerbation Definition
Asthma exacerbation is defined as a progressive increase in shortness of breath, cough, wheezing, or chest tightness, or any combination of these symptoms
Corticosteroids (Inhaled Corticosteroids=ICS)
Maintanence and control of chronic asthma through the suppression of activated inflamatory genes in the airway epithelial cells
First line therapy in mild, moderate and severe asthma as it is considered to be the most effective long term therapy
ICS in Asthma versis COPD
It is considered to be a first line of defense in asthma but not for COPD
Not considered first line therapy for treatment of COPD (used in combination: ICS/LABA). This is because COPD has a different pattern of inflammatory cells in comparison to asthma (neutrophils are seen in COPD). Oral and ICS do not influence the inflammatory changes driven by neutrophils.
Patients with stable COPD should not be given systemic steroids.
Antiallergic Agents
Mediator antagonists (Nonsteroidal)
Agents that are prophylactic, antiallergic, antiasthmatic
Act as antagonists to mediators of inflammation
These are not steroids
Includes Anti-Leukotrienes like Singulair
Leukotriene Inhibitor
(LTRA’s: Leukotriene Receptor Antagonists)
Zafirlukast – ACCOLATE
Zafirlukast (ACCOLATE)
Indications
For the prophylaxis and chronic treatment of asthma
Effective in preventing bronchoconstriction and other asthmatic airway responses in allergen, exercise and cold air challenges
Zafirlukast (ACCOLATE)
Mode of Action
Selectively competes for leukotriene receptor LTD4 and LTE4 sites, preventing the inflammatory response of airway contractility, vascular permeability and mucus secretion.
Inhibits asthma reactions induced by exercise, cold air, allergen and aspirin
Leukotrienes are more potent than histamines in causing bronchospasm.
They are also potent stimulants of mucus secretion
Oral Vs. Inhaled
- Oral will inhibit early and late phase asthma and cause modest bronchodilation
- Inhaled format inhibits early phase only
Montelukast-Singular
Indication for Use
For the prophylaxis and chronic treatment of asthma
Effective in preventing bronchoconstriction and other asthmatic airway responses in allergen, exercise and cold air challenges
Approved for use in children as young as 6 months
Useful for mild-moderate asthma,
Also approved for allergic rhinitis
Montelukast-Singular
Mode of Action
Selectively competes for leukotriene receptor LTC4, LTD4 and LTE4 sites, preventing the inflammatory response of airway contractility, vascular permeability and mucus secretion.
Leukotrienes are more potent than histamines in causing bronchospasm.
Also inhibits both early and late phase bronchoconstriction
Montelukast-Singular
Side Effects
Laryngitis, pharyngitis, cough
Nausea, diarrhea, pain
Otitis, sinusitis
Zileuton – ZYFLO
Indication for Use
This drug is indicated for the prophylaxis and chronic treatment of asthma, and is approved for use in adults and children over 12 years of age
It is a controller not a reliever and has no use in an acute asthma attack
Zileuton – ZYFLO
Mode of Action
Leukotriene receptor antagonist like Accolate.
Inhibits the formation of leukotrienes from arachidonic acid. By interrupting the synthesis of these biologically active leukotrienes their contribution to the inflammatory responses in asthma is effectively blocked
Inhibits the 5-LO enzyme which would otherwise catalyze the formation of leukotrienes from arachidonic acid
Zileuton – ZYFLO
Hazards and Side Effects
Headache, neck pain
General pain
Abdominal pain
Loss of strength
Nausea, vomiting, constipation, flatulence
Liver enzyme elevations
Recommend monitoring liver enzymes during treatment – liver enzymes may decrease or return to normal during tx or after discontinuation
Contraindicated in patients with acute liver disease or with elevated liver enzymes
Taken at meals and at bedtime.
BIOLOGICS (Anti Immunoglobulin E (Anti IgE)
Xolair – Omalizumab
An injectable Biologic used with Asthmatics with allergic components that are not well controlled with maximized conventional therapy. Biologic means made of animal or human protein – genetically engineered
It is an anti-IgE monoclonal antibody that inhibits the immunologic cascade by blocking IgE
Expensive treatment not covered by all drug programs
Symptoms are inadequately controlled with inhaled corticosteroids.
Xolair has been shown to significantly decrease the incidence of asthma exacerbations and improve control of asthma symptoms in these patients.
Safety and efficacy have not been established in other allergic conditions.
Anaphylaxis rare. However, can occur after first dose or 1 year into treatment therefore, pt. must be monitored appropriately following injection
Omalizumab - Xolair
Indicated for the treatment of moderate to severe asthma in adults and peds (>12 years old) who have a positive skin test to aeroallergen
Patients must have S.Q injections every 2 or 4 weeks – comes in a 150 mg vial, dependent on the weight and serum IgE level of the patient
Issues: Anaphylaxis, expensive, requires an injection, duration of treatment
Anaphylaxis rare – can occur after the first dose or 1 year into tx,
Pharmacokinetics – after administration – absorbed slowly – peak effect in 7-8 days, excreted by the liver, half-life of aprox 26 days (may be weight related – increasing weight, increases clearance)
Not indicated for acute relief of SOB
Not a replacement for inhaled corticosteroids
Not optimal as monotherapy in persistent asthma
May allow reduction of high-dose ICS or allow for decreasing of ICS dos
May allow reduction in asthmatic rescue agents
Beclomethasone Dipropiontae
Inhaled Corticosteroids
QVAR
Triamcinolone Acetonide
Inhaled Corticosteroids
azmacortt
Flunisolide
Inhaled Corticosteroids
Aerobid
AeroBid-M
Fluticasone Propionate
Inhaled Corticosteriods
Flovent
HFA
Flovent
Diskus
Ciclesonide
Inhaled Corticosteriods
Alvesco
Budesonide
Inhaled Corticosteroid
Pulmicort
Turhuhaler
Momestasone Furate
Inhaled Corticosteroid
Asmanex
Twisthaler
Methylprednisolone
SYSTEMIC CORTICOSTEROIDS
Medrol
Solu-Medrol
Hydrocortisone
SYSTEMIC CORTICOSTEROIDS
Solu-Cortef
SALMETEROL
LONG-ACTING 2-AGENTS (LABA)
SEREVERT
Formoterol
LONG-ACTING 2-AGENTS (LABA)
Foradil
Arformoterol
LONG-ACTING 2-AGENTS (LABA)
Brovana
Fluticasone/Sameterol
INHALED CORTICOSTEROIDS AND LABA
Advair Diskus
Budesonide/Formoterol
INHALED CORTICOSTEROIDS AND LABA
Symbicort
Cromolyn Sodium
MAST-CELL STABILIZING AGENTS
Intal
Zafirlukast
LEUKOTRIENE INHIBITORS (ANTILEUKOTRIENES)
Accoclate
Montelukast
LEUKOTRIENE INHIBITORS (ANTILEUKOTRIENES)
Singulair
Aminophylline
XANTHINE DERIVATIVES
Aminophylline, Theo-Dur
Asthma Rates
Asthma rates continue to increase in both sexes however self reported rates are higher in women than in men
COPD vs. Asthma PFT
COPD FEV1/FVC >70% and FEV1 < 80% of predicted in response to bronchodilator therapy
If post bronchodilator therapy FEV1 increases > 0.4 L then the COPD pt. may also have underlying asthma and will benefit from a combined therapy of bronchodilators and inhaled steroids
COPD vs. Asthma Lab Results
COPD-Increases in neutrophils and macrophages
Asthma-Increases in eosinophils inflammation
COPD vs. Asthma Management
COPD-Non drug oriented that is more focused on rehab
Asthma-Drug oriented
COPD vs Asthma-Age of Onset
COPD-> 40 yrs of age
Asthma- < 40 yrs of age
COPD vs Asthma-Smoking history
More common in COPD
COPD vs Asthma-Sputum Production
Asthma-Infrequent
COPD-Often
COPD vs Asthma-Allergies
Asthma-Often
COPD-Infrequent
COPD vs Asthma-Clinical Symptons
COPD-Presistent and Progressive
Asthma-Intermittent and Variable
COPD vs Asthma-Disease Course
COPD-Progressively worsening
Asthma-Stable
COPD vs Asthma-Airway Inflammation
COPD-Neutrophils
Asthma-Eosinophils
COPD vs Asthma-Response to Inhaled Corticosteroids
COPD-Helful in patient with moderate to severe disease
Asthma-Essential
COPD vs Asthma- Role of bronchodilator
COPD-Regular therapy
Asthma-Only use as needed
COPD vs Asthma-Exercise
Asthma-Rarly used
COPD-Essential
What does hyperractivity of the airways lead to?
Bronchoconstriction & bronchospasm, mucosal swelling, and increased production of thick tenacious mucus.
What are signs, symptoms, and observations of asthma?
Increased respiratory rate, work of breathing, heart rate, cardiac output, and blood pressure. The patient may also have a prolonged (forceful) expiration and a decreased peak expiratory flow rate.
What happens when mediators are released in asthma?
Bronchoconstriction, bronchospasm, pulmonary vasodilation, airway inflammation, and increased mucus production.
What are some special medications used for asthma?
Luekotriene antagonist, Montelukast Sodium (Singulair).
What are some prophylactic medications used for asthma?
Cromolyn (intal) and Nedocromil (tilade).
When would you use Xolair (omalizumab) to treat asthma?
It can be used to treat patient that are 12 years of age and above. They must have a moderate to severe persistent asthma have asthma triggered by year-round allergens in the air, and continue to have asthma symptoms even though they are taking inhaled steroids.
True or False: A methacholine challenge test can be used in the diagnoses of asthma.
True. A methacholine challenge test is performed to determine how reactive or responsive your lungs are to different asthma triggers in the environment. The test can help your doctor evaluate symptoms suggestive of asthma and help diagnose whether or not the patient has it.
What is an allergen?
They affect only people allergic to a specific substance.
What is an irritant?
The effect everyone if the dose is high enough.
What are some examples of irritants?
Tobacco smoke, wood smoke, chemicals in the air, ozone, perfumes, household cleaners, cooking fumes, paints, and varnishes.
What are some occupational irritants?
Vapors, dust, gases, and fumes.
What are some other common causes of asthma?
Viral and sinus infections, exercise, reflux disease herd, medications (NSAIDS), beta blockers, and emotional anxiety.
What are the types of medications that help with asthma symptoms?
Antihistamines, decongestants, anti-inflammatory agents, anti-leukotrienes, bronchodilators, and anticholinergics.
What are the 3 types of medications that are used as anti-inflammatory agents?
Mast cell stabilizers, corticosteroids, and bronchodilators.
What are the classes of bronchodilators available for asthma?
Beta-agonist bronchodilators, methylxanthines, and anticholinergics.
What are methylxanthines?
PDE inhibitors such as theophylline, aminophylline, and theobromide.
How do anticholinergics work?
They block the veal nerve in bronchoconstriction and can be used alone or along with bronchodilators. Some examples include Atrovent and Spiriva (tiotropium bromide). These are better for COPD rather than asthma.
What are the 6 goals for the effective management of asthma?
(1) To prevent chronic and troublesome symptoms, (2) to maintain normal breathing, (3) to maintain normal activity levels including exercise, (4) to prevent recurrent asthma flare-ups, (5) to minimize the need for emergency room, and (6) to provide optimal medication therapy with no or minimal effort.
What are the rules of 2 for asthma medications that tell you that your asthma is not under control?
You use a rescue inhaler more than 2 times a week, you awaken at night with asthma symptoms more than 2 times a month, you use more than 2 canisters a year of rescue medications (inhaler).
What are quick-relief medications?
Short-acting beta-2 agonists, inhaled anticholinergics, short-acting theophylline, epinephrine/ adrenaline injection.
What are examples of long-term asthma medications?
Corticosteroids, tablets or syrup steroids, mast cell stabilizers, long-acting beta-2 agonist, sustained-release tablets, sustained release methylxanthines, anti-leukotrienes.
What is immunotherapy?
It’s a form of antigen extract to desensitize the patient to asthma triggers. It can help to reduce asthma symptoms, as well as the need for medications. It can also help reduce the risk of severe asthma attacks after future exposure to the allergen. It has been shown to possibly be as effective as inhaled steroids.
If the PaCO2 rises drastically and suddenly during an asthma attack, what does that mean?
It likely means that the patient isn’t moving any air and may be going into respiratory failure. This is a very dangerous situation and may require intubation and mechanical ventilation.
What will a PFT test show on an asthmatic?
Decreased airflow, low peak flows, and an increased residual volume. The FVC may be decreased due to air trapping, and the FEV1/FVC ratio is decreased.
What happens to the systolic blood pressure during an asthma attack?
It will decrease during inspiration by 10-20 mmHg.
Which WBC increases during an asthma attack?
Eosinophils.
What is Pulsus Paradoxus?
It is an abnormally large decrease in the patient’s stroke volume, systolic blood pressure and pulse wave amplitude during inspiration.
What is Asthma
- Asthma is a condition in which a person’s airways become inflamed, narrow and swell, and produce extra mucus, which makes it difficult to breathe.
- The disease is chronic, obstructive, inflammatory, and varies with different levels of severity.
- There will be recurring episodes of paroxysmal dyspnea, wheezing on expiration and inspiration caused by constriction of the bronchi, coughing, and viscous mucoid bronchial secretions.
- The episodes may be precipitated by inhalation of allergens or pollutants, infection, cold air, vigorous exercise, or emotional stress.
- It’s essentially hyperreactivity of the airways
Hyperreactivtiy in Asthma
During the course of inflammation bronchial hyperreactivity will occur
- In comparison to healthy people the airways of patient with asthma react more sensitive to various stimuli
- The consequence is paroxysmal and recurring obstruction in the airways
Atopic Syndrome
Allergic type of asthma often exists in combination with other diseases pertaining to the atopic syndrome, such as allergic rhinitis or neurodermatitis.
What Does All Extrinsic Asthma HAve in Common
- They all have in common a polygenic predisposition for excessive production of IgE.
Intrinsic Asthma Causes
- Causes can include
- Stress
- Cold or dry air
- Smoke
- Noxious inhaled agents
- GERD
- Anxiety
- Acetylsalicylic acid/NSAIDs
- Analgesic Asthma Syndrome
- Viruses
- Infections.
The two Types of asthma
- Often, the two types cannot be rigorously distinguished especially when they occur in adult asthmatics. Only 30 % of patients suffer from a purely extrinsic or intrinsic asthma; the rest display hybrid forms of both types.
Pathophysiology of Extrinsic Asthma
- After a few minutes of coming into contact with a corresponding allergens IgE antibodies will appear
- These antibodies will activate mast cells, which will release mediators such as leukotriene, prostaglandin, and histamine
- Type 1 hypersensitivity reaction
- These mediators will cause bronchospasm and attract inflammatory cells
- The inflammatory cells will create long term chronic inflammation
Pathophysiology of Intrinsic Asthma
- The immunological process is similar to extrinsic asthma but without a triggering allergen, rather there is infectious agents (viruses) that can be triggering factors
Classic Signs of Asthma
- Shortness of breath
- Expiratory stridor
- Chronic cough
- Mostly dry and in spasms (cough variant asthma)
- Thoracic tightness
- Symptoms respond to appropriate anti-asthma therapy
What part of the airway is mainly involved in astham
- Mainly involves the medium sized and small bronchi
Spirometry for Asthma
- Improvement in FEV1 >/= 12% and >/= 200 mL
% Improvement= [(Post FEV1-Pre FEV1)/ Pre FEV1] x 100
Asthma and PFT
- An essential part of diagnosis asthma is the PFT
- In a PFT an obstruction with an increase in airway resistance can be observed
- FEV1 is reduced
- Given an approximately constant vital capacity, this yields a reduced Tiffeneau-Pinelli index: FEV1 / VC < 70 %.
- A decisive factor in differential diagnosis (e.g. in comparison to COPD) is the reversibility of the obstruction, tested in a bronchodilator reversibility test
- The FEV1 value improves significantly either directly after administration of inhaled bronchodilator medication (e.g., 400 μg salbutamol) or in case of a lack of response, after administration of inhaled glucocorticoids over 4 weeks.
- If the pulmonary function testing does not show any abnormalities despite suspected asthma, a provocation test (methacholine challenge test) can confirm a diagnosis.
- The patient inhales methacholine or histamine, and due to the hyperreactivity of the airways, this provokes bronchoconstriction, which leads to a reduced FEV1 value by least 20 % and a doubling of resistance.
- The following inhalation of salbutamol dilates the bronchial tubes and normalization of the pulmonary function parameters should be achieved.
ABG With Mild Asthma Attack
- pH
- Increased
- PaCO2
- Decreased
- Due to hyperventilation
- HCO3
- Slightly Decreased or Normal
- PaO2
- Normal
ABG With Moderate Asthma Attack
Acute Alveolar Hyperventilation with Hypoxemia (Acute Respiratory Alkalosis)
- pH
- Normal
- PaCO2
- Normal
- HCO3
- Normal
- PaO2
- Normal but starting to decrease
ABG with Severe Asthma Attack
Acute Alveolar Hyperventilation with Hypoxemia (Acute Respiratory Alkalosis)
- In severe asthma attacks, it will be a case of impending respiratory failure
- pH
- Decrease
- PaCO2
- Increase
- HCO3
- Decrease
- PaO2
- Severe Decrease
Cardiac Asthma Differential diagnosis
- Patients with left-sided heart failure who have developed a lung congestion with shortness of breath. Bilateral basal rales during auscultation of the lungs and a chest x-ray with signs of pulmonary congestion lead to the right diagnosis.
