Respiratory system Flashcards
1
Q
FRC: functional residual capacity
A
- volume of gas remaining in lung after completion of a normal breath
- change w/ position & activity
- reduced: supine, GA, surgery
- preserve: PEEP or recruitment maneuvers
2
Q
TLC: total lung capacity
A
- total volume of gas in lungs at maximum inspiration
- Increased: OPD
- Reduced: restrictive lung disease
3
Q
VC: vital capacity
A
- maximum volume expired after a max inspiration
2.
4
Q
dynamic lung volumes
A
- TV: tidal volume
- IRV: inspiratory reserve volume
- ERV: expiratory reserve volume
5
Q
inspiratory capacity
A
IRV+TV
6
Q
static lung volumes
A
- RV
- TLC
- FRC
Note: can not be measured by spirometry;
Can: gas dilution (helium), nitrogen washout, whole-body plethysmography
7
Q
CC: closing capacity
A
- lung volume below which small airways start to collapse–>alveoli collapse–>atelectasis
- increase: smoking, obesity, aging, supine
- CC=FRC: 44 yo healthy in supine, 66 yo upright position
8
Q
CC: closing capacity (cont.)
A
- CC > FRC–> as expiration nears completion and the lung capacity falls below CC–> airways begin to collapse–>atelectasis–> dyspnea and hypoxemia
- PEEP from 5 to 10 cm H2O –> increase FRC above CC–> small airway collapse and improve oxygenation.
9
Q
Forced Vital Capacity (FVC)
A
- volume that can be expired after a maximal inspiration
2. reduced: COPD, restrictive lung dz, poor pt cooperation during testing
10
Q
Forced Expiratory Volume (FEV)
A
volume expired after a maximal inspiration over a specific amount of time, generally one second (FEV1)
11
Q
Forced Expiratory Flow (FEF 25-75% )
A
- Decreased flow rates of the medium sized airways are identified by this test
- earlier detection of obstructive disease and being more independent of patient cooperation
12
Q
Maximum Voluntary Ventilation (MVV
A
maximum ventilation that the subject can perform in one minute
13
Q
DLCO = Carbon Monoxide Diffusing Capacity
A
- predictor of perioperative mortality but not long-term survival
- Predicted post-lung resection DLCO of less than 40% is the strongest single predictor of high risk for pulmonary complications and mortality
- less than 20% of predicted place a patient in a very high-risk category for respiratory complications; this risk may be prohibitive for anything other than immediately life-saving surgery
14
Q
VO2 max
A
maximum oxygen consumption by the subject
15
Q
How much pressure needs to be applied during a recruitment maneuver to expand all atelectasis?
A
40 cm H2O
