Lecture 2/3 Flashcards
Two lung function tests
- spirometry
- peak flow meters
how many times do you need to do spirometry to confirm results
three times
three stages of spirometry
regular breathing, deep breath in, big blow out
4 variables healthy lung size and function is dependent on
age, sex, height, race
three numeric values of clinical importance for interpretation
1) Forced vital capacity (FVC)
2) forced expiratory volume in the first second (FEV1)
3) FEV1/FVC ratio
Forced vital capacity FVC
total amount of air that can be expelled from full lungs
FEV1
the amount of air expelled during the first second of the spirometry maneuver
FEV1/FVC
The fraction of air exhaled in the first second relative to the total exhaled
Vital Capacity
a volume of a full breath exhaled in the patient’s own time and not forced
Reversibility Testing
determination of airflow limitation reversibility using drug administration.
Why is reversibility testing done
to detect patients with reversible airway obstruction
Reversibility is positive if
FEV1 changes by ~12% and FVC changes by ~200mL
what is administered prior to reversibility testing
larger doses of bronchodilators
3 limitations of spirometry
pt needs to show effort and cooperation
clinical context is important (need suspicion to get spirometry)
normal values may not be reflective
age for spirometry
6 years and over
Asthma diagnosis general
reduced FEV1/FVC, and increased FEV1 after bronchodilator therapy
Asthma diagnosis children
FEV1/FVC = <0.8-0.9 AND FEV1 increase greater than or equal to 12%
Asthma diagnosis adults
FEV1/FVC = <0.75-0.8) AND FEV1 increase greater than or equal to 12% minimum >200mL
Peak flow Meters short term benefits
confirm diagnosis of asthma
assess response to treatment
establish a baseline for management of exacerbations
long term benefits of peak flow meters
managing patients asthma
identify environmental causes of asthma symptoms
instructions for peak flow meter
blow out hard and fast in a single blow.
how do things show up on chest x rays - bone or metal
all white or completely radiopaque
how do things show up on chest x rays - water (soft tissue)
white to grey
how do things show up on chest x rays - fat
gray
