Respiratory & Endocrine (PHAR 253) Flashcards
What do pulmonary function tests measure?
- Lung capacity
- How quickly air can move in and out of lungs
- Gas exchange efficiency
What are the four compartments of air in the lungs?
Tidal Volume: air exhaled during normal respiration
Inspiratory Reserve Volume: maximum air inhaled above TV
Expiratory Reserve Volume: maximum air exhaled below the tidal volume
Residual Volume: volume of air remaining in the lungs after maximal expiration
The sum of the above four components is defined as the total lung capacity (TLC)
What is the functional residual capacity?
This is the volume of air in the lungs at the end of normal expiration
What is vital capacity?
This is the total volume of air exhaled after a maximal inhalation
What are some airflow measures used in pharmacy?
FEV1 (Forced Expiratory Volume in 1 second)
FVC (Forced Vital Capacity)
FEV1/FVC ratio
What is FEV1?
Forced Expiratory Volume in 1 second
Patient inspired to TLC and exhales maximally. The volume of air exhaled in the first second
This is the best measure for assessing severity of airflow obstruction
What is FVC?
Forced Vital Capacity
This is the total volume of air expired as rapidly as possible from TLC
How is FEV1/FVC clinically relevant?
Helps to differentiate restrictive from obstructive lung disease
ex. FEV1=4L of air and FVC=5L, FEV1/FVC ratio is 80%
What are the types of pulmonary function tests?
- Spirometry
- Peak Expiratory Flow Meter
- Carbon Monoxide Diffusing Capacity
What are some potential uses for spirometry?
The following is not an exhaustive list:
- Diagnosing lung disease and assessing severity
- Monitoring the course of disease or result of therapeutic intervention
- Assessing surgical risk
How does a patient take a spirometry test?
The test should be conducted by trained personal who follow a quality assurance program
- Take the deepest breath
- Exhale into the sensor as hard as possible for at least 6 seconds
What are the results of spirometry compared against?
- Predicted normal values based on height, age, and sex
- Patient’s “Personal Best” lung function (particularly helpful to monitor progression or treatment of disease states)
What is a limitation of spirometry?
Requires full cooperation of the patient
This can be challenging for some patient groups (children under 6, dementia patients, etc.)
What are some contraindications for spirometry?
Spirometry causes the following and could be damaging in certain disease states
- Increases intracranial or intraocular pressure
- Increases in intra-thoracic and intra-abdominal pressure (avoid especially if patient had a thoracic procedure)
- Increases in mycardial demand or changes in BP
- Increased risk of infection
What is obstructive lung disease?
The inability to get air out of the lung (asthma and COPD)
FEV1 is reduced, therefore FEV1/FVC ratio is lower
What is restrictive lung disease?
The inability to get air into the lung and maintain normal lung volumes (interstitial lung disease, patients that are not fully cooperating)
FEV1/FVC ratio is either normal or increased
What is the utility of conducting spirometry tests when diagnosing asthma?
After a patient is confimed to have an obstructive lung disease. Practitioners must determine if it is asthma or COPD
When an asthma patient is given salbutamol (beta 2 agonist), their airways will open up. This will increase FEV1 (acute bronchodilator response).
If the use of salbutamol does not change FEV1, it is likely this obstructive lung disease is COPD
Why are peak expiratory flow rate devices not preferred to measure pulmonary function?
Although they are more portable, they have less reproducible results
Results are compared to personal best or predicted values
What is Carbon Monoxide Diffusing Capacity?
It is a measurement of the ability of carbon monoxide to diffuse across the alveolar-capillary membrane
What happens to CO Diffusing capacity when the lungs are diseased?
This capacity will be reduced in all clinical situations where gas transfer from alveoli to capillary blood is impaired
What do pulse oximeters measure?
They help determine oxygenation status
In what situations will pulse oximeters give an inaccurate reading?
- Patients who are cold
- Wear dark nail polish
- Patient is in shock
- Patient has smoke inhalation
Why are arterial blood gas levels important in determing pulmonary function?
ABG’s reflect how well lungs are oxygenating the blood and are useful to assess acid-base status
What is asthma?
It is a chronic inflammatory disorder of the airways characterized by the following:
- Sudden occurence or persistent symptoms
- Dyspnea, chest tightness, wheezing, sputum production and cough
- Airway hyper-responsiveness to a variety of stimuli
Do pediatric asthma patients “grow out” of asthma ?
Yes many patients no longer have asthma or a less severe form in adulthood
What is the prognosis of asthma?
If asthma is adequately managed, then the following apply:
Most do not die from long-term progression of asthma
Lifespan is unaltered
Can maintain all activities of daily living
What is the etiology of asthma?
Genetic predisposition (60-80%)
Environmental factors (smoke, allergens, cold air)
Drugs (Aspirin and other NSAIDs, sulfites, non-selective b-blockers, etc.)
Sex (males affected initially, but women are affected more by asthma after 20)
Obesity
What is the difference between atopic and non-atopic asthma?
Atopic (Extrinsic): asthma is in response to allergy to antigens
Non-atopic (Intrinsic): Secondary to chronic/ recurrent infections. Hypersensitivity to bacteria and viruses
What are some predictive factors that contribute to persistebt adult asthma?
- Atopy
- Onset during school age
- Presence of bronchial hyperactivity
What are the consequences of untreated bronchial hyperactivity in asthma?
Without anti-inflammatory treatment, airway remodelling can occur
What does the early asthmatic response look like?
Occurs in minutes (bronchospasm)
Activation of mast cells and macrophages
What does the late asthmatic response look like?
Occurs in hours
Bronchospasm returns, submucosal edema, hyperresponsiveness
Activation of inflammatory cells
What does chronic asthma look like?
Occurrs in days
Hyperreactive airways, epithelial cell damage, mucous hyper secretion
Leads to airway remodelling
What are the two asthma phenotypes?
Type 2 and Type 1
What are some examples of Type 2 asthma?
Early onset allergic asthma
Aspirin exacerbated respiratory disease (AERD)
Exercise-induced asthma
What are some examples of Type 1 asthma?
Obesity-related asthma
Very late onset asthma
Smoking-related
Cormorbidities
What are the four elements of asthma diagnosis?
- Medical history
- Physical exam
- Pulmonary Function Tests
- Other laboratory tests (CBC, Allergy skin tests, sputum test)
When diagnosing asthma, what information should a practitioner collect for a good history?
Symptoms and severity:
Most patients with asthma will experience intermittent episodes of expiratory wheezing, coughing and dyspnea
Family history
Precipitating factors
Triggers
What are some common triggers for asthma?
- Exercise
- Time of day
- Aero-allergens
- Irritants
- Respiratory tract infections
- Drugs (Aspirin and other NSAIDs in particular)
- Stress
- Hormonal fluctuations
- GERD
Are physical exams for asthma always useful?
No, asthma is a heterogeneous disease and it can present different signs or symptoms at different times
This can make gauging severity of asthma difficult
What is the pulmonary function criteria for asthma diagnosis?
FEV1/FVC is less the 75-80% below predicted values
and
More than 12% improvement in FEV1 and at least 200mL from baseline 15 min post quick acting b-2 agonist challlenge (shows reversibility)
Is the threshold for diagnosis for children more conservative or liberal compared to guidelines for adults?
It is a more conservative threshold (FEV1/FVC ratios below 80-90% are grounds for asthma diagnosis and treatment in children)
What are some other laboratory tests used in the diagnosis of asthma?
CBC (eosinophil count, IgE concentration, FeNO (breath test))
Allergy skin tests
Sputum eosinophils
What are the two organizations that create asthma guidelines?
- Canadian Thoracic Society (Clinical guideline)
- Global Initiative for Asthma (less clinical, but practcal guideline)
Which criteria were modified in the new CTS guidelines for asthma control?
- Daytime symptoms: No more than 2 days/week
- Need for a reliever (SABA or budesonide/formoterol): No more than 2 doses per week
Under this new definition, more people will be classified with having uncontrolled asthma
When is a patient considered to have well controlled asthma?
- Avoid symptoms during the day and night
- Need little or no reliever medication
- Have productive, physically active lives
- Have normal or near-normal lung function
- Avoid serious asthma flare ups
What are the six principles of asthma treatment?
- Environmental control
- Pharmacologic treatment
- Appropriate use of inhalation therapy
- Regular consultation with certified asthma education
- Graduated approach to therapy
- Regular follow up
What are some environmental control measures for asthma patients?
Avoid animals (use HEPA filters and wash pets if you already have animals in your home)
Mold/fungus (use dehumidifier and fix leaky pipes)
Minimize outdoor activity when pollen/poor air quality
Avoid allergens
Maintain personal hygiene
What are the two main categories of pharmacological therapy used in asthma?
- Reliever medication (only use for acute flare-ups)
- Controller medication (take everyday, and it acts slowly over time)
What is an example of a reliever medication used in asthma?
SABA (selective b-2 adrenergic agonists)
ex. Salbutamol
These drugs have little impact on long-term inflammation reduction, but they can be used in acute situations
Are beta-1 or beta-2 agonists better for asthma treatment?
beta-2 agonsists specificially activate receptors in the lungs. b-2 agonism causes dilation of the airways
This action by b-2 agonists is preferred over different types of adrenergic agonists
Are drug interactions with SABAs common?
No, DIs are not awfully common because SABAs are not always absorbed into the blood, but some concerns exist
Be careful when using beta blockers and a SABA (oppose the actions of one another)
QT prologation possible
What is a common dose for SABAs in asthma patients?
Usually dosed 1-2 puffs every 4-6 hours PRN
In a serious asthma attack, it is safe to take puffs every few minutes
How do long-acting beta agonist (LABA) work?
They work slowly over 12h period
Need to take LABAs every day
Formoterol is special because it is approved for rescue
What drug class is the most common and effective type of controller?
Inhaled Corticosteroids (ICS)
ICS can take days, weeks, and months to see changes in controlled asthma
What are some side effects for inhaled corticosteroids?
Side effects are dependent on drug, dose, and inhalation technique irritation
- Dysphoria, hoarseness, throuag itching, and cough
- Candida oral infections
- Growth retardation in children
What are some patient education points that pharmacists should convey to their patients about LABAs?
LABAs need to be taken regularly, daily and delayed onset
Use spacer if provided to younger child.
Rinse out mouth following every inhaler use
What are some contraindications for inhaled corticosteroids?
Do not start using ICS during untreated respiratory tract infections
What is the utility of oral or intravenous corticosteroids?
They are used for short periods of time in acute, severe asthma
What are some commonly used oral/IV corticosteroids used in asthma?
- Prednisone
- Prednisolone
- Dexamethasone
What is the utility of Leuktriene Receptor Antagonists in asthma treatment?
They are an alternative to increasing steroid doses in patients who remain symptomatic
Can LABAs be used without corticosteroids?
No, LABAs can never be used alone. They must be used in conjuction with a corticosteroid
Use a combo product for convienence and full adherance
What is the utility of Methylxanthines in asthma?
Less effective bronchodilators than beta agonists
Used as a add on therapy for patients that need high dose corticosteroid (used in severe asthma cases)
Also require close monitoring due to narrow therapeutic index
What was the first biologic for asthma?
Omalizumab (anti IgE antibody)
Used for atopic asthma that is poorly controlled despite high dose steroids and and add on therapy
Which biologic has EDS coverage for asthma?
Mepolizumab
It is useful in patients with eosinophillic asthma who experience exacerbations despite of high doses of inhaled corticosteroids
What is the role of tiotropium in asthma treatment?
Tiotropium is used as an add-on therapy for patients over the age of 12 for asthma that is uncontrolled despite combo ICS/LABA therapy
Why should patients avoid increasing the frequency of their SABA over adding ICS?
Excessive SABA use on its own can increase mortality rates, but using an ICS in conjunction can reduce mortality rates
What is the rationale against using SABA alone?
ICS + LABA vs. SABA alone = 2/3 reduction in exacerbations with a lower ICS dose
Which patients are at higher risk for exacerbations?
- History of a previous severe asthma exacerbation
- Poorly controlled Asthma as per CTS criteria
- Overuse of SABA (more than 2 inhalers of SABA in a year)
- Current smoker
What is the minimum age required for Symbicort (budesonide/formoterol)?
need to be at least 12 years old