limbiks_Exam 3 Lecture 2 Flashcards
Where is the vast majority of oxygen found in the blood?
Hemoglobin
In what forms does CO2 float around in the blood?
Bicarbonate and carbon amino compound
What is the composition of the first portion of expired air?
No nitrogen
What is the significance of the appearance of N2 during expiration?
Transitional phase
How can we estimate anatomical dead space during expiration?
No nitrogen and halfway to midpoint of transitional phase
What is the rule of thumb for determining anatomical dead space?
1 cc per pound of body mass
How much anatomical dead space does a 70 kg (approximately 150 pounds) person have?
150 cc’s
Does being overweight or obese add any anatomical dead space?
No
What primarily affects the amount of anatomical dead space a person has?
Overall size of the frame/body size
What information can be obtained by plotting volume on one axis and air flow speed on the other axis?
Useful info about vital capacity
What is the concern regarding peak expiratory flow rate during expiration?
Total lung capacity
What happens to the airflow rate during this process?
Picks up very quickly
What is the reason behind having a lung volume just below total capacity?
Effort, elastic recoil of the lung, surface tension
When are the airways about as open as they’re going to be?
At very high lung volume
What happens with higher lung volume?
Fuller alveoli and wider airways
Why is there rapid movement of air out of the system at TLC?
Fuller alveoli and wide airways
How fast can the air move out of the system at TLC for an average person?
About 10 liters per second
What is the ratio that is used to assess lung function?
FEV1 / FVC
What is the normal value for the FEV1 / FVC ratio?
80%
What does a lower FEV1 / FVC ratio indicate?
Obstructive lung disease
What does a higher FEV1 / FVC ratio indicate?
Restrictive lung disease
How does the FEV1 / FVC ratio change in restrictive lung disease?
It doesn’t change much
What does a lower low ratio imply?
Obstruction like asthma or Zima
When are we typically worried about obstructions?
On expirations
Main concern:
Obstructions
Obstructions can be:
Fixed or nonfixed
Fixed vs nonfixed:
Inside/outside chest
What does an extra thoracic obstruction represent in a drawing of the trachea?
Problem outside the chest
What does an intra thoracic obstruction represent in a drawing of the trachea?
Problem inside the chest
What is the characteristic of most obstructions in the respiratory system?
Variable
What type of obstructions are the vast majority of variable obstructions?
Intra thoracic
Problem with asthma attack?
Expiring
Problem with variable intra thoracic obstruction
Expiration
Reason for expiration being a problem?
Intra thoracic obstruction is an airway obstruction
Reason for force affecting airways?
Force applied to get air out of lungs
Why is a lack of connective tissue or springs in airways a significant problem?
Vulnerable to collapse
When are the airways more vulnerable to collapse?
Forced expiration
What happens if there is a variable intra thoracic obstruction during inspiration?
No problems on inspiration
What pulls an obstruction out of the way during inspiration?
Negative pressure
Where is the negative pressure generated that can pull an obstruction out of the way?
In the chest
What type of obstruction is affected by negative pressure pulling it out of the way?
Intra thoracic obstruction
What does a variable intra thoracic obstruction cause concern for?
Selective compression or resistance to outflow during expiration, specifically forced expiration
What is another type of obstruction besides intra thoracic?
Extra thoracic obstruction
What is an example of an extra thoracic obstruction that is variable?
Paralyzed vocal cords
What happens to the airways during negative pressure breathing?
Pulled open
What happens when there is a paralyzed vocal cord and negative airway pressure?
Obstruction during inspiration
During expiration, what happens with a variable extrathoracic obstruction?
Positive intrathoracic pressure pushes obstruction out of the way
What type of obstruction is a problem on inspiration?
Not expiration
What is an example of a fixed obstruction?
Endotracheal tube
What effect does an endotracheal tube have on the trachea?
Creates a fixed obstruction
Why does an endotracheal tube affect both inspiration and expiration?
It has a fixed inner diameter
Where is the problem indicated in a flow volume loop due to an endotracheal tube?
Both inspiration and expiration
What is an example of a fixed intra or extra thoracic obstruction?
Endotracheal tube
How are the peak inspiratory and expiratory flow rates limited in fixed obstructions?
Straight line
What does a variable extra thoracic obstruction affect?
Inspiration
What does a variable intra thoracic obstruction affect?
Expiration
What axis on a flow-volume loop shows airflow?
Liters per second
What axis on a flow-volume loop shows volume?
Time
Can a flow-volume loop be plotted without a time axis?
Yes
What should a normal person have lost about after one second of a forced expiratory maneuver from total lung capacity?
80% of the vital capacity
How much volume should a normal person have exhaled by the first second of the maneuver?
about 4 liters
What is the ratio of FEV1 over FVC for this person?
80%
What does the total volume loss during expiration tell us about?
The vital capacity
What are the two main differences in the tracing of the sick patient compared to a normal person?
Lower vital capacity and lower forced expiratory volume
What is the normal vital capacity for a person?
Four and a half liters
What is the vital capacity of the sick patient in the tracing?
3 liters
How does the forced expiratory volume of the sick patient compare to a normal person?
Substantially lower
How many Liters should a normal person be able to get out?
3.5 Liters
What is the measured amount mentioned in the text?
3.6 liters
What was the estimated amount mentioned by the speaker?
4 liters
What is the FEV1 of a person with serious airway obstructions?
1.5 Liters
What is the FVC of a person with serious airway obstructions?
3 Liters
What is the normal FEV1/FVC ratio?
80%
What is the FEV1/FVC ratio of a person with serious airway obstructions?
50%
How long does it take to exhale the first 1.5 Liters of air in a person with serious airway obstructions?
1 second
How long does it take to exhale all the air in a person with serious airway obstructions?
7 seconds
What is considered the lower limit of normal for FEV1/FVC ratio?
0.5
What is the FEV1/FVC ratio for the first person?
76%
What is the vital capacity for the second person?
3 L
What is the FEV1 for the second person?
2.5 L
What is the FEV1/FVC ratio for the second person?
83%
What is the characteristic feature of restrictive lung disease on pulmonary function tests?
Low vital capacity, normal FEV1/FEVn ratio
How does vital capacity change in restrictive lung disease?
It is low
What is the ratio when dividing 1.75 L by 2 L?
87%
What does a normal or high ratio usually indicate in lung function?
Restrictive lung disease
What disorder is likely indicated by an altered flow volume loop?
Obstructive disorder
What is the normal peak expiratory flow rate?
10 L
What is the peak expiratory flow rate?
About 3L
How much air is exhaled in the first second?
1.5 L
How is the patient’s vital capacity described?
Lower than normal
What observation is made about the rest of the vital capacity coming out?
Takes an awful long time
What is an indicator of obstructive lung disease?
Lower FEV1 than normal
What is the normal range for FEV1?
3.8 - 4
What does a lower than normal FEV1 indicate?
Obstructive lung disease
In COPD, what lung function test is consistently abnormal?
FEV1
What is expected when FEV1 is low?
FEV1/FVC ratio to be low
What change do we typically see with TLC in COPD?
TLC should be elevated
COPD
RV, FRC increased
Restrictive disease (Fibrosis)
FEV1, FVC decreased
What do the flow volume loops in the Guyton review manual show?
Different levels of effort
What does the biggest loop effort ‘W’ indicate in a flow volume loop?
RV up to total lung capacity
What do increasing curves on a flow volume loop represent?
Deeper breaths
What does the smallest curve on a flow volume loop represent?
Smallest tidal volume
What is shown in the top part of a flow volume loop?
Tidal volumes
What is depicted on the left side of the flow volume loop?
Time course of force expiration
How can one determine the depth of breath from a flow volume loop?
By the size of the curve
What does a deeper curve indicate on a flow volume loop?
Deeper breaths
How many liters have come out of the patient?
3 liters
What is the vital capacity at total lung capacity?
5 liters
At what point has 3 liters of air been squeezed out by the green line?
One second mark
How many liters of air has each person exhaled?
3
What might the FEV1/FVC ratio indicate if it’s normal?
Green, Restrictive lung disease.
What do the pictures show?
Patient’s air exhalation.
What does the FEV1/FVC test measure?
Lung emptying speed.
When might the lung emptying process be interfered with?
Patient sickness.
What percentage of atmospheric nitrogen should be in the air?
79%
What is the nitrogen concentration in the lungs after displacement by water vapor?
75%
How much pressure of water vapor is in the lungs?
47 mmHg
What would happen if we breathed 100% oxygen?
Dilute nitrogen in lungs
Amount of dilution in each breath
Alveolar portion of tidal volume
Nitrogen concentration in a set of lungs
75%
Time to remove all nitrogen from lungs
Long
What nitrogen concentration should a healthy person be able to achieve in the lungs in seven minutes of breathing?
2.5%
How many minutes of breathing should it take for a healthy person to reach the 2.5% nitrogen concentration in the lungs?
seven
How does COPD affect lung nitrogen?
Takes longer to blow out nitrogen
What does the blue line on the graph represent?
COPD patient
What does the black line on the graph represent?
Healthy patient
What do the data points on the graph represent?
Samples of expired air
What is the result of uneven ventilation?
Blue line shows inconsistency between dots
How would uneven ventilation affect the dilution process?
Takes more breaths for dilution
What is the defining feature of unhealthy lungs in a nitrogen dilution test?
Uneven ventilation
Does tidal volume affect the dilution?
Yes
What plays a role in dilution along with tidal volume?
Lung volume
Can lung diseases like COPD impact nitrogen washout?
Yes
Which lung diseases may not have a significant effect on nitrogen washout?
Restrictive diseases like sarcoidosis or fibrosis
Volume at the beginning of the transitional phase?
150ml expired air
Volume of the transitional phase?
100cc
What is the total expired air up until the alveolar plateau?
200ccs
How much is the anatomical dead space in this case?
150 ccs
Is the graph easy to understand?
No
What is the Closing Capacity test?
A dilutional nitrogen pulmonary function test.
What does the Closing Capacity test measure?
The dilutional effect of a large breath of 100% Oxygen.
How does the Nitrogen washout method work?
By looking at expired nitrogen concentration after breathing 100% oxygen.
What is the purpose of the closing capacity test?
Assess lung function
What lung volumes are involved in the closing capacity test?
FRC to RV
What gas is inspired during the closing capacity test?
100% Oxygen
TLC
6 liters
FRC
1.5 liters
N2 at FRC and RV
75%
N2 at TLC
Diluted by 100% O2
What volume of 100% oxygen was added?
4.5 liters
What was the initial total air volume?
1.5 liters
What percentage of the initial volume was nitrogen?
75%
How was the nitrogen concentration affected by adding oxygen?
Diluted out by a lot
Typical value of nitrogen concentration after adding 4.5 L of pure oxygen to the lungs?
25-30%
Method for calculating nitrogen concentration after adding oxygen
Add quantity of nitrogen at RV + 4.5L
What happens to nitrogen concentration when adding oxygen
Decreases
What is done after reaching total lung capacity?
Hook patient up to a nitrogen analyzer
What is analyzed in the expired breath of the patient?
Quantity of nitrogen
What is plotted as a function of expired air?
Quantity of nitrogen coming out
What is the initial step in measuring expired gas?
Voluntarily exhale, inhale oxygen, inhale deeply
What is phase three similar to in Fowler’s test?
Plateau phase
What is the main difference between phase three in this test and Fowler’s test?
Larger expired volume
What aspect are we more interested in during phase three of this test?
Other aspects of usefulness
What is phase four in lung volume measurement?
Sharp upstroke of expired nitrogen
What is the closing volume?
Volume of air expired during phase 4
How is the closing volume related to ERV?
Very similar
Lung Volume at Residual Volume (RV)
Alveoli at base: 20% full
Lung Alveoli at RV
Alveoli at apex: 30% full
Air Volume Capacity at RV
Alveoli at apex: 70%
What percentage of their total capacity must be added to the bottom of the lung to achieve 100% fullness during vital capacity inspiration?
80%
What percentage of their total capacity needs to be added to the top (apical) of the lung to achieve 100% fullness during vital capacity inspiration?
70%
What happens when we breathe in air without nitrogen?
Alveoli become 100% full
Effect of breathing extra fresh air in alveoli at the bottom of the lung?
Nitrogen concentration knocked down a lot
Effect of breathing extra fresh air in alveoli at the top of the lung?
Nitrogen concentration diluted out but less than at the base
Where in the lung is nitrogen concentration higher in expired air?
Top of the lung
Why is nitrogen concentration lower in expired air from the base of the lung?
Diluted more during deep breath
What should the initial concentration of expired nitrogen be?
None
What happens after the initial phase in expired nitrogen concentration?
Transitional phase leading to plateau
Does the plateau phase of expired nitrogen concentration have a slope?
Yes, a little
What occurs after the plateau phase in expired nitrogen concentration?
Abrupt increase
At the beginning of the plateau phase, where does most of the air come from?
From the base of the lung
What happens at the end of the plateau phase?
Abrupt spike in expired nitrogen
Why does the abrupt spike in expired nitrogen occur?
Small airways at the base of lung collapse
What is closing volume?
Volume where the base of the lung starts collapsing
What happens when the airways at the base of the lung close?
No nitrogen coming from those alveoli
Why is there a larger amount of expired air from the top of the lung when the base closes?
Proportionate change
Why is the base of the lung more prone to collapse in older age?
Loss of traction, springs, and elastic tissues
Why is airway collapse unlikely in healthy 20 year olds?
Healthy lungs
At what age does airway collapse become more common?
50
Which lung airway structures are prone to collapse first during expiration?
Airways at base of lung
What causes the upstroke of phase IV in Schmidt’s drawing graph?
Less air from base, more from top
What might it indicate if the upstroke of phase IV occurs earlier than expected?
Earlier airway collapse, or reduced traction, or less elastic recoil, or more pseudo-obstructive lung disease
What is a simple and sensitive test to assess lung health?
Closing volume closing capacity test
Why is the closing volume closing capacity test preferred?
Quick, easy, cheap, sensitive
How does the aging process affect lung performance?
Not a big deal due to safety factor
Why is this test sensitive?
To airway collapse tendency
Why is closing volume expected to be low in young individuals?
It should be a low number in somebody who’s young.
What is closing capacity?
Combination of residual volume plus closing volume.
How does closing capacity differ from FRC?
Very similar to FRC but varies more with normal aging.
What change occurs in closing capacity as people age from 20 to 70 years old?
Closing capacity increases with age
At what age is the closing capacity very close to the residual volume?
Age 20
What happens to the closing capacity at the base of the lungs during normal breathing at age 20?
No collapsing airways
What is the impact of age on the breathing process?
More laborious for older individuals
Where is the operating range typically for airways regarding closing capacity?
Around FRC or above ERV line
What happens if closing capacity exceeds FRC?
Airway collapse at the end of every expiration
What happens to elastic recoil springs as we age?
Lose elasticity
What happens to nephrons as we age?
Lose nephrons
Increased load on the remaining nephrons can lead to what?
Issues
When do most organ systems start to decline?
Upper 30s or 40s
At what age do we start experiencing decline in lung function?
20 years
What is the number 1 rule in medicine according to the text?
Don’t get sick and don’t get old.
What happens to the closing volume as you get older?
Shifts towards higher lung volume
Why do older people have difficulty breathing?
Work of breathing increases due to uncoordinated expiratory maneuvers.
