03 - Lung Volumes Flashcards
When a volume is not affected by the rate if air movement, it is called
Static lung volume
What are volumes?
A single measurement of abstract fragmentation of the lung
What is capacity?
Combined volumes
What is a normal tidal volume?
Normal breath volume
About 2500-3000 cc
How many cc is a normal breath? How much of total lung capacity is that?
400-500 cc
About a tenth or twelfth
What is expiration reserve volume? How much is it?
The additional volume that can be forcefully squeezed out after a normal exhalation
About 1100 cc
What is residual volume? How much is it?
Volume remaining after forced exhalation.
About 1200 cc
What is functional residual capacity?
The volume at the end of a normal TV.
About 2300 cc
How is FRC calculated?
FRC = ERV + RV
How does the gas that makes up FRC get there?
Gas moves in by diffusion during exhalation
How does FRC contribute to efficient gas exchange during apnea?
FRC acts as a reserve during apnea so that patients are less likely to desaturate
What is needed in order to have good preoxygenation?
A good seal and adequate time
What is the difference between preox for three minutes and three vital capacity breaths?
Longer reserve period in patients who breathe for three minutes because they have more venous oxygen
Arterial oxygen is the same for both
What is inspiration reserve volume
Amount that can be inhaled after a TV
About 3000 cc
What is inspiration capacity?
Ins capacity = IRV + TV
What is vital capacity?
The biggest breath possible
VC = IRV + ERV + TV
How is total lung capacity calculated and how much is it?
TLC = IRV + ERV + RV + TV
About 5800 cc
If contractility of the lungs/diaphragm or abdominal muscles decreases, forced vital capacity ______________
Decreases
What are the two components of expiration?
Active and effort independent
What is forced expiration volume (FEV^1)?
The expiration volume in the first second
Why is one second chosen for FEV^1?
In one second, 70-80% of air has gotten out of the lungs and can help diagnose obstructive or restrictive lung disease
What happens to the following with anesthesia?
FRC
Compliance of the lungs
Airway resistance
FRC decreases
Compliance of the lungs decreases
Airway resistance increases
Emphysema _________ the airway, limiting further expiration.
Collapses
Patients with obstructive lung disease have a ________ time getting air _______ the lungs in the first second
Harder, out of
What is maximal voluntary ventilation (MVV)?
The measure of how much motor activity and how well muscles work
MVV is measured by taking breaths as
Deep and fast as possible
The volume in the lungs where the airway and alveoli begin to collapse is called
Closing capacity
Closing capacity normally occurs below the
FRC
What factors can increase closing capacity?
Age
Smoking
Intrinsic lung disease
Positioning
An FRC ________ can cause collapse.
Below normal
What part of the lung is closest to its maximum size?
Toward the apex because there is less weight of lungs
Which part of the lungs is easiest to collapse?
The base
FRCis the balance of the recoiling forces between
The lung and chest wall
The size of the lung at FRC is larger than what it wants to be and the chest wall wants to expand outward
FRC can be affected by
Body habitus Sex Posture Age Lung disease Diaphragmatic tone
How does obesity limit lung expansion?
More weight is pushing on the chest wall and abdominal pressure is also increased, which pushes up on the diaphragm
Males have larger lung capacities than women. This is not much of an issue because women have
Less oxygen requirement than men
Upright people have _______ to help keep pressure away from the lungs.
Gravity
Which positions can decrease FRC?
Supine
Trendelenberg
As people age, their lung capacity ________ and their closing capacity ________.
Decreases, increases
A floppy diaphragm results in
Smaller lung volumes
Airway resistance depends on
Fluid and resistance
Flow with the lowest resistance
Laminar flow
Flow that occurs in large airways
Laminar flow
Flow with high resistance
Turbulent flow
Flow that results from high flow velocity
Turbulent flow
Occurs between laminar and turbulent flow
Transitional flow
What is Poiseuille’s Law?
Resistance is inversely proportional to radius^4
R = (8nL)/(pi x r^4)
What happens to resistance as lung volumes increase?
Resistance decreases
_____ of airway resistance comes from the bronchus (medium bronchioles).
80%
Why does resistance and turbulent flow increase with emphysema?
The elastic component of the lung is destroyed and radial traction outward is reduced
Air. Trapping occurs in patients with
Obstructive lung disease
Chronic obs pulm disease
What is air trapping?
The abnormal retention of air in the lungs where it is difficult to exhale completely
Two examples of OLD?
Asthma
Brochiolitis obliterans
Two examples of COPD?
Emphysema
Chronic bronchitis
