Lung Volumes to CO Poisoning Flashcards
Define tidal volume
the volume of one “normal” breath
Define minute volume
total air inhaled and exhaled in one minute
-tidal volume x respiration rate
Approximately how much of a persons tidal volume is actually involved in respiration
~70%
What is the anatomical dead space
the ~30% of a tidal volume that is not involved in respiration
Define alveolar ventilation rate
The volume that actually reaches the respiratory zone in one minute
-70% x minute volume (tidal volume x respiration rate )
Define inspiratory reserve volume
the air volume you can take in, over the tidal volume by a forceful inhalation
Define expiratory reserve volume
the amount of air volume you can exhale over your tidal volume
Define residual volume
the air that cannot be exhaled from the alveoli or the non collapsible airways
Can residual volume be determined by spirometry
No
Define inspiratory capacity
tidal volume + inspiratory reserve volume
Define expiratory capacity
tidal volume + expiratory reserve volume
Define vital capacity
inspiratory reserve volume+ tidal volume + expiratory reserve volume
Define total lung capacity
Vital capacity + residual volume
What 3 factors is alveolar air dependent on
- composition of inspired air
- alveolar ventilation
- concentration of dissolved gases in mixed venous blood
What 2 gas laws are important for respiration and what do they state
Dalton’s law= the total pressure of mixed gas is calculated by adding all the partial pressures of the gases that compose the mixed gas
Henry’s law= the quantity of gas that will dissolve in a liquid is proportional to the partial pressures of the gas and its SOLUBILITY
Why is Dalton’s law important for respiration
partial pressures determine the movement of O2 and CO2 from the:
- atmosphere and the lungs
- lungs and the blood
- blood and the tissue
gas flows from high partial pressure to lower partial pressure
Why is Henrys law important for respiration
In body fluids the ability for a gas to stay in solution is greater when its partial pressure is greater and when its solubility is higher
so we can drive O2 into the tissue by increasing pO2
What is the clinical application of Henrys law
hyperbaric chambers
What gas has higher solubility O2 or CO2
CO2 , 24 times as much
In external respiration is the diffusion of O2 from the alveoli to the blood and diffusion of Co2 from blood to the alveoli dependent on each other
No these 2 flows are independent of each other
How does surface area affect gas exchange
the more surface area the faster and easier gas exchange is
How does diffusion distance affect gas exchange
With greater diffusion distance, you get less gas exchange
How does the the build up of interstitial fluid effect diffusion distance
more fluid =greater diffusion distance= less gas exchange
Define PaO2
the partial pressure of dissolved unbound O2 in arterial blood
Define SaO2
measurement of O2 that is bound to Hgb in arterial blood (so before tissue)
Define SpO2
measurement of O2 that is bound to Hgb peripherally, it is what is measured by pulse oximeter
What O2 measurement are from arterial blood draws
PaO2 and SaO2
How does a pulse oximeter measure SpO2
colorimetric measurement
Does CO or O2 have a higher affinity for Hgb
CO
In CO poisoning what type of measurements will you see in PaO2, SaO2, and SpO2 and why
PaO2 = increases, because CO knocks of O2 from Hgb so more O2 is dissolved in plasma
SaO2= reduced, because CO is bound to Hgb not O2
SpO2= stays the same, because carboxyHgb and oxyHgb are both red
