PFTs and Asthma Flashcards
What are the basic PFTs?
- Airflow spirometry
- Lung volumes
- Diffusion Capacity of the lungs for carbon monoxide (DLCO)
What can be measured with airflow spirometry?
- Forced Vital Capacity (FVC)
- Forced Expiratory Volume in first second of expiration (FEV-1)
- FEV-1/FVC Ratio
What PFT aspect is the most useful information for obstruction?
FEV-1
How many times should spirometry be performed?
Repeat testing at least 3 times
What classifies an airway disease as reversible?
If there is reversibility, what disease are you most likely dealing with?
If FEV-1 increases by 12% AND 200 mL
Asthma
How is bronchodilator testing performed?
Patient inhales 2-4 puffs of medication and hold it in lungs for 5-10 seconds. Spirometry is then completed 15 minutes later.
What constitutes a positive Methacholine Challenge Test (Bronchoprovocation)?
FEV-1 decreases by 20%
What are examples of obstructive diseases?
Are there issues with expiration or inspiration?
COPD, asthma, bronchitis
Expiration
What are examples of restrictive diseases?
Are there issues with expiration or inspiration?
Fibrosis, infectious lung disease, pleural effusion
Inspiration
Define Total Lung Capacity (TLC)?
Volume of air within the lung after maximal inhalation
Define Vital Capacity (VC)?
Volume of air we breath out following maximal inhalation
Define Residual Volume (RV)?
Volume of air remaining in the lungs following maximal exhalation
What does DLCO measure?
When can this be misleading?
Measures the ability of the lungs to transfer gas and saturate the hemoglobin (alveolar-capillary membrane)
Can be misleading in anemia and must be adjusted for hemoglobin level
In DLCO testing, what will occur in healthy versus diseased lungs?
In healthy lungs, little CO is collected during exhalation
In disease lungs, less CO diffuses into lungs and higher levels are measured in exhaled gas
Is the following seen in obstructive or restrictive lung disease:
Inspiration and expiration will overall look normal, but flow and volume are reduced
Restrictive
Is the following seen in obstructive or restrictive lung disease:
Reduction in lung volume
Restrictive
Is the following seen in obstructive or restrictive lung disease:
TLC: Increased FVC: Normal RV: Increased FEV-1: Decreased FEV-1/FVC: Decreased
Obstructive
Is the following seen in obstructive or restrictive lung disease:
TLC: Decreased FVC: Decreased RV: Decreased FEV-1: Decreased FEV-1/FVC: Normal or increased
Restrictive
What must the FEV-1/FVC ratio decrease to to classify it as an obstructive process?
Decreased to 70% or less
What is the hallmark symptom of asthma?
Wheezing
What are symptoms typically associated with asthma?
- Nocturnal coughing with duration longer than 3 weeks
- Wheezing
What physical exam findings are associated with asthma?
- Increased AP diameter (air trapping)
- Wheezing with prolonged expiratory phase (mostly heard on forced expiration)
- Associated signs of rhinitis, sinusitis, URI, atopic dermatitis
What are signs of severe obstruction in asthma?
- Tachypnea
- Tachycardia
- “Tripod positioning”
- Accessory muscle use
- Pulsus paradoxus (different pulses during inspiration vs. expiration)
What is included in the ASA Triad/Samter’s Triad?
Sinus disease with nasal polyps, ASA sensitivity, severe asthma
If patient has aspirin-exacerbated respiratory disease (AERD), what should you include in patient education?
- Avoid NSAIDS
- Avoid alcohol (75% also have respiratory response to alcohol)
What is included in the Atopic Triad?
Atopic dermatitis, allergic rhinitis, asthma
What testing can help confirm the diagnosis of asthma?
Spirometry
5 year old patient presents with the following:
- Symptoms 2 days a week or less
- 2 or less nighttime awakenings per month
- FEV-1 > 80%
- FEV-1/FVC is normal
- Normal activity
- SABA use to control symptoms 2 days or less per week
How would you classify this case of asthma and what would the recommended treatment be?
Step 1: Intermittent asthma
Treatment:
SABA PRN
5 year old patient presents with the following:
- Symptoms greater than 2 days a week but not daily
- 3-4 nighttime awakenings per month
- FEV-1 > 80%
- FEV-1/FVC is normal
- Minor limitation in activity
- > 2 days per week of SABA use to control symptoms (not daily)
How would you classify this case of asthma and what would the recommended treatment be?
Step 2: Mild persistent asthma
Treatment: - SABA PRN - Low dose ICS daily OR LTRA/Cromlyn (used in children)
5 year old patient presents with the following:
- Daily symptoms
- More than 1 nighttime awakenings per week
- FEV-1 is 60-80%
- FEV-1/FVC is reduced by 5%
- Some activity limitations
- Daily use of SABA to control symptoms
How would you classify this case of asthma and what would the recommended treatment be?
Step 3: Moderate persistent asthma
Treatment: - SABA PRN - Medium dose ICS (all ages) OR Low dose ICS + LABA if 5 or older (or LTRA)
5 year old patient presents with the following:
- Symptoms throughout the day
- Nighttime awakenings are nightly
- FEV-1 < 60%
- FEV-1/FVC is reduced by 5%
- Extremely limited physical activity
- SABA used to control symptoms several times per day
How would you classify this case of asthma and what would the recommended treatment be?
Step 4: Severe persistent asthma
Treatment:
- Refer to specialist
- SABA PRN
- Medium dose ICS + LABA (or LTRA in 0-4)
What is the preferred treatment in Step 5 asthma?
- SABA PRN
- High dose ICS + LABA (or LTRA in ages 0-4)
- Consider adding Xolair for ages > 12 with allergies
What is the preferred treatment in Step 6 asthma?
- SABA PRN
- High dose ICS + LABA (or LTRA in ages 0-4) + oral steroids
- Consider adding Xolair for ages > 12 with allergies
What is considered well controlled asthma?
What should follow up look like?
- Symptoms 2 days per week or less
- Less than 2 nighttime awakenings per month
- FEV-1 is > 80%
- FEV-1/FVC is > 80%
Follow-up initially 1-3 months then every 3-12 months depending on severity
When would you order an ABG for asthma symptoms?
What would you see on the ABG?
Order ABG is O2 levels are low
Will see respiratory alkalosis initially due to hyperventilation; if PaCO2 is normal though you should consider the patient getting tired/breathless
How should an acute asthma exacerbation be treated?
When should the patient follow-up?
- O2
- SABA/SVN of Albuterol or Xopenex +/- Ipratropium Bromide
- Systemic corticosteroids
- Abx PRN
- Respiratory monitoring
- C-PAP, BiPAP, or intubation if severe
Follow-up within 1 week
