Measures the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled to evaluate a broad range of lung diseases
spirometry
Reasons for spirometry test (5):
- diagnose lung diseases (asthma, bronchitis, emphysema)
- cause of SOB
- chemicals at work
- check lung function before surgery
- see affect of meds and progress
The amount of air inspired during normal, relaxed breathing
about 500 ml
tidal volume
the additional air that can be forcibly inhaled after the inspiration of a normal tidal volume
inspiratory reserve volume
3.1 L
the additional air that can be forcibly exhaled after the expiration of a normal tidal volume
expiratory reserve volume
1.2L
the volume of air still remaining in the lungs after the expiratory reserve volume is exhaled
residual volume
1.2L
the maximum amount of air that can fill the lungs
total lung capacity
6L
the total amount of air that can be expired after fully inhaling
vital capacity
4.8 L
the maximum amount of air that can be inspired
inspiratory capacity
3.6 L
the amount of air remaining in the lungs after a normal expiration
functional residual capacity
about 2.4L
volume of gas exhaled in one second by a forced expiration from full expiration
FEV1
the percent of forced vital capacity that is exhaled in the first second
normal FEV1/FVC ratio
80%
- involves difficulty exhaling all the air from the lungs
- because of damage to the lungs or narrowing of airways inside lungs, air comes out more slowly than normal
- at end of full exhalation, abnormally high amount of air still linger in the lungs
obstructive lung disease
like pink puffers
- results from a condition causing stiffness in the lungs
- stiffness of chest wall, weak muscles, or damaged nerves may cause restriction in lung expansion
restrictive lung disease
- the FEV1 is reduced due to obstruction of air escaping from the lungs
- FEV1/FVC ratio is <70%
obstructive disease
the FEV1 and FVC are equally reduced due to fibrosis or other lung pathology
the ratio should be approximately normal, or increased
FEV1 > 80%
restrictive disease
chronic obstructive disease
Arterial blood gas measures: (4)
- pH
- pO2
- pCO2
- HCO3
test used to determine gas exchange which reflects gas exchange at the alveolar-capillary membrane
arterial blood gas
If PaO2 < ______ mmHg, supplemental oxygen should be administered.
If PaO2 < ______ mmHg, the patient is at risk of death and must be oxygenated immediately.
60 mmHg
26 mmHg
In an ABG, ______ indicates whether a metabolic problem is present.
bicarbonate
The ______ is an indicator of CO2 production and elimination.
paCO2
a low paCO2 indicates _______, or overventilation.
hypocapnia
Normal ABG pH
7.35 - 7.45
