DSA - Respiratory Adaptations Flashcards
What is the equation for alveolar O2?
inspired O2 - consumed O2
What does the respiration quotient tell us and what is the equation?
Tells the relationship of CO2 and O2 exchange
VCO2 / VO2
What is a normal value of RQ?
0.8
How do you get from the atmospheric pressure to the actual amount of oxygen that you breathe in?
- You subtract 47mm Hg (water vapor pressure at body temperature) from 760 mmHg to get 713 mm Hg
- Since oxygen makes up 21% of the air that we breathe in, you multiply 713 by 0.21 to get 149.7 mmHg
What are the three ways in which the human body can obtain fuel?
- Glucose
- fatty acids
- a mixture
What is the RQ if the body is ONLY using glucose as energy?
1
What is the RQ if the body is using free fatty acids as energy?
0.7
What would the RQ be if the patient is receiving an IV glucose solution?
1.0
What would the RQ be for a patient who is hypoglycemic or a diabetic?
0.7
What is the overall point of the alveolus?
To bring the alveolar oxygen and the arterial oxygen into equilibrium with each other
What is the equation for the alveolar arterial O2 gradient?
PAO2-PaO2
***normal is <12 mmHg
What should you be thinking physiologically if the alveolar arterial gradient is high?
Process of gas exchange was impaired by some disease process
The _______ _________ ______ is the ratio between the amount of air getting into the alveoli and the amount of blood being sent to the lungs
ventilation perfusion (V/Q) ratio
______ is bringing the oxygen into the lungs and removing CO2 from the alveoli
Ventilation
______ is removing the O2 from the alveoli and adding CO2
perfusion
Under normal conditions, ____ liters of ventilation each minute enter the respiratory tract while ____ liters of blood go through the pulmonary capillaries.
4
5
What is the normal value for PAO2?
100 mmHg
What is the normal value for PACO2?
40 mmHg
What is the normal value for PaO2?
95-100 mmHg
What is the normal value for PaCO2
40 mmHg
A decreased in the V/Q ratio is produced by either _____ ventilation or ______ blood flow
Decreasing
Increasing
What happens physiologically if there is a decrease in ventilation?
There is not enough O2 being brought in to meet the metabolic need and not enough CO2 is leaving, so there is an increased amount of CO2 in the body (acidotic)
What happens physiologically if there is an increase in perfusion?
More blood cells are coming to deliver O2 to the cells and then taking more CO2 to the alveoli than will be expired
Increase in CO2…acidotic
What are the three things that you should consider with a decrease in the V/Q ratio?
- Ventilation is not keeping pace with perfusion.
- The alveolar oxygen levels will decrease, which will lead to a decrease in arterial oxygen levels (PaO2)
- The alveolar CO2 levels will increase (we’re not getting rid of it as fast), also leading to an increase in arterial CO2.
What are 2 ways that the V/Q ratio can be increased
Increase ventilation
Decrease perfusion
What is happening in an increased V/Q ratio?
ventilation is in excess of the metabolic needs being met by perfusion so we blow off more CO2 and the PAO2 increases
____ _______ is when one of the two variables (ventilation or perfusion) changes and it is matched with a change in the other variable
V/Q mismatch
***also the term for when there is a variety of V/Q ratios throughout the lung
When you stand up the V/Q ratio (INCREASES/DECREASES) because there is more blood going to the base of the lung while less air gets there
LOWERS
Which portion of the lung is described by the following characteristics?
- less blood
- high ventilation
- high V/Q ratio
- High PAO2 and PaO2
- Decreased CO2
Apex of the lung
Which portion of the lung is being described based on the following characteristics?
- Low V/Q ratio
- Low PAO2 and PaO2
- Increased CO2
Base of the lung
An increase in V/Q to infinity is produced when perfusion goes to _______
zero
In a patient, regions of zero blood flow will result from a _______ _______ that blocks the blood flow.
pulmonary embolism
What will be seen in the blood in the case of a pulmonary embolism?
The blood will be very oxygenated and low CO2
***levels will come close to atmospheric
How do we decrease the V/Q ratio to zero?
stop ventilation to a part of the lung
-blood is sent to alveoli that do not have fresh air coming to them so the blood that results looks similar to the venous blood
effort was wasted in pumping the blood to the lungs