Diagnostic and Therapeutic Skills - Pulmonology Flashcards
measured against predicted values derived from large studies of healthy people of same height, weight, sex and race.
what type of PFT is this?
Spirometry, Plethysmography
what are the Types of PFTs
- Spirometry, Plethysmography
- Diffusing Capacity, 6 Minute Walk Test, Peak Flow
indications for PFTs
- Evaluate patients with respiratory symptoms or rib fracture
- Assess progression of previously diagnosed lung disease
- Monitor the efficacy of treatment
4.Evaluate patients preoperatively - Monitor for potentially toxic side effects of certain drugs
considerations for PFTs
- Patient cooperation and consistent effort is essential
- > 5 y/o can perform
volume of air inspired or expired with each normal breath at rest
tidal volume
maximum volume of air that can be inspired over and above the tidal volume
Inspiratory reserve volume (IRV)
volume of air that can be expired after the expiration of the tidal volume
Expiratory reserve volume (ERV)
volume of air that remains in the lungs after maximal exhalation
Residual volume (RV)
Non-invasive assessment of maximum inspiratory and expiratory volume as well as maximal expiratory effort
- Spirometry
- Completed bedside, in pulmonary lab or as an incentive spirometer
- May be performed pre- and post bronchodilator
indications for spirometry
- diagnostic and monitoring of lung and neuromuscular diseases that affect breathing
- prevention of post-surgical/traumatic pulmonary complications
CI/cautions for spirometry
- recent (<6wks) since abdominal, intracranial, or eye surgery or a pneumothorax
- thoracic, abdominal and cerebral aneurysms
- unstable angina or a recent MI
- acute severe asthma, acute respiratory distress, active TB
Minimal risk - dizziness, rarely syncope occurs
what Lung volumes are assessed with spirometry
- Vital capacity (VC)
- Forced vital capacity (FVC)
- Forced expiratory volume in one second (FEV₁)
- FEV₁/FVC
- Peak expiratory flow (PEF) rate
- Forced expiratory volume over the middle half of expiration (FEF25-75)
Measures the total volume of air held in the lungs
Gold standard for PFTs
Plethysmography
Indicated if decreased FVC on spirometry
Plethysmography
volume measurements in plethysmography
- Total Lung Capacity¹ (TLC)
- RV+VC = TLC - Vital capacity (VC)
- Functional Residual Capacity² (FRC)
- ERV + RV = FRC - Expiratory reserve volume (ERV)
5.Residual Volume (RV) - RV/TLC
difficulty exhaling air from the lungs during PFT
what is your interpretation?
obstructive
difficulty expanding the lungs during inhalation during PFT
what is you interpretation?
Restrictive
3 lung volumes to initiate plethysmography interpretation
- FVC - amount of air moved after the deepest breath possible
- FEV₁ - amount of air moved in the first 1 second
- TLC - total amount of air in the lungs at maximal inspiration
what are the 3 values reported in a PFT
- Actual value - what the patient performed
- Predictive values - what the patient should have performed
- Based upon healthy patients of the same height, age, sex, ethnicity - Percent predicted - a comparison of the actual value to the predicted value
Assessed during plethysmography
Measures respiratory muscle strength
what is this PFT
Maximal respiratory pressures
Pre- and Post-bronchodilator Responsiveness during PFT
- Adults: increase in FEV1 > 12% AND FVC > 0.2 L
- 5-18 y/o: increase in FEV1 > 12%
indications for Maximal respiratory pressures
unexplained decrease in VC or suspected respiratory muscle weakness
Procedure: forced expiration (with cheeks bulging) through a blocked mouthpiece after a full inhalation.
most sensitive PFT
assesses the transfer of oxygen and carbon dioxide
Diffusing Capacity (DLCO)
procedure of Diffusing Capacity (DLCO)
- patient inhales carbon monoxide (CO) + tracer gas (methane or helium)
- holds for 10 sec, exhales forcefully
- exhaled air tested to determine amount of tracer gas remaining
A result a >80% is normal
assesses oxygenation during exertion and the distance a patient can walk
6 minute walk test (6MWT)
patients walks back and forth on flat surface 100 ft in length
with 6 minute walk test (6MWT), you must monitor:
symptoms (dyspnea and fatigue) at rest and progression of symptoms with walking
oxygen saturation at rest and while walking
what is a normal 6MWT
1300 - 2300 feet, asx with pulse ox maintained above 95%
Measures peak expiratory flow (PEF) rate
Utilized to determine adequate control of asthma
Peak Flow
how are predicted values of peak flows determined?
- Height and Age
- Predicted values for African American and Hispanic are appx 10% less
interpretation of peak flow
- GREEN = 80-100% (p) “All clear”
- YELLOW = 50-80% (p) - “Caution”
- Implement treatment plan prescribed by PCP - RED = Below 50% (p) - “Medical Alert”
- Contact provider and start bronchodilator therapy immediately