Lung Tests and Measures Flashcards
What is tidal volume and how can you objectively measure it?
Its the amount of air in a normal breath
You can measure it with a tape measure
Whats IRV?
Inspiration Reserve Volume (max amount of air you can take in after you’ve already taken a normal breath)
What is ERV?
Expiration Res Volume (max amount of air exhaled after you’ve taken a normal breath)
What is RV?
Residual volume (volume of gas that remains in the lungs at the end of ERV)
Which patient population may have a higher RV?
COPD patients
What is TLC?
Total Lung capacity
IRV+TV+ERV+RV
What is VC and how can you measure it?
Vital Capacity
Max amount of air you can force out of the lungs after max inspiration
Measure with a tape measure
What is IC?
Inspiration Capacity
max amount of air inspired from resting expiration levels
What is FRC?
Functional residual capacity
volume of air remains at rest expir levels (ERV+RV)
Give some examples of an obstructive lung disease?
COPD
Bronchitis
Asthma
Give some examples of a restrictive lung disease
Cirrhosis
Fibrosis
Poor posture
What is a normal value for TV?
400-700 mL
What is a normal respiration rate (RR)?
12-20 breaths/min
What is a normal Minute ventilation? (TVxRR)
5-10 L/min
What can cause a higher min ventilation?
hypoxia, hypercapnia, acidosis, increase dead space vol, anxiety, exercise
What can decrease min ventilation?
hypocapnia, alkalemia, resp center depression, neuromuscular disease
What is dead space in the lungs/
Volume in lungs that is not perfused with capillary blood flow (125-175 mL)
What can increase dead space in the lungs?
PE
pulmonary HTN
What is alveolar ventilation?
Volume of air that participates in gas exchange
This is where you get your ABG values
What is pulmonary function tests (PFT) important for?
Assists in evaluation of cardiopulmonary status
Assessment of strength and endurance of respiratory mmt
What is FVC?
Forced vital capacity (max volume of gas that can be expired forcefully
What causes FVC and VC to be smaller than normal?
Restrictive lung disease
What is FEV1?
Forced expiratory volume in 1 second
Why would FEV1 be smaller in patients with an obstructive disorder?
Decreased elasticity makes it harder for air to expire
What are normal FEV1/FVC ratio?
75-85% = normal
How can you tell if it’s an obstructive or restrictive disorder using FEV1/FVC?
The ratio will be smaller in obstructive patients
In restrictive patients, the ratio will still be in normal limits
How can you measure respiratory endurance?
Measure maximum voluntary breaths they can do per min)
What are ABG analysis done for?
measure pH
ventilation
and oxygenation
What are the normal ABG values?
PaO2 >80 mm Hg
PaCO2 = 35-45 mm Hg
pH = 7.35-7.45
HCO3 = 22-26 mEq/L
Is respiratory strength measured on inspiration or expiration?
Inspiration
