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21 Cards in this Set
- Front
- Back
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In a normal person, A-a gradient is roughly ... mmHg.
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5
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Respiratory Gases in the air:
Nitrogen = ...% Oxygen = ...% CO2 = ...% |
79
21 <1 |
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PO2 of air = ...
PO2 of inspired air = ... PO2 of alveolar air = ... Alveolar gas contains about ... mmHg of oxygen and about ... mmHg of carbon dioxide. |
160
150 100 100 40 |
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at 38 degrees C, the partial pressure of water is about ... mmHg
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50
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Alveolar-Air equation:
look at slide 5 |
ok
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normal value of the respiratory exchange ratio is ...
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0.8
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normal A-a gradient is less than ... usually
... in A-a gradient is bad (could be due to diffusion barrier or shunting) ... in A-a gradient is good. Everything that you have in the alveoli is going into the arterial blood. |
10
Increase Decrease |
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Physiological shunt = ... shunt (2-5%) + ... shunt (Normal is from 2-8%)
... shunt has 2 parts: 1) absolute shunt, where the V/Q ratio is 0 (0.5%) 2) low V/Q ratio (4.5%) |
anatomical
intrapulmonary Intrapulmonary |
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Effects on A-a gradient:
respiratory causes -diffusion impairment - ... -physiological shunt - ... -general hypoventilation - ... -regional and local low V/Q - ... nonrespiratory causes -intracardiac R to L shunt - ... -decreased Pio2, low Pb, low Fio2 - ... -reduced O2 content (anemia and CO poisoning) - ... |
increased
increased normal increased increased normal normal |
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determination of shunt fraction equation:
look at slide 11 |
ok
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determination of shunt fraction:
[O2]c = ... ml/100ml of blood [O2]a = ... ml/100ml of blood [O2]v = ... ml/100ml of blood |
20
18 14 |
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Anatomical shunt fraction:
To calculate the anatomical shunt fraction of blood in pts breathing 100% O2, assume that 1% cardiac output is shunted for every ... mmHg of A-a gradient. Ex. (PAO2 – PaO2) = 670 – 70 = 600 mmHg % Shunt = ... Normal A-a gradient is about 50-60 w/ 100% O2 |
20
600/20 = 30% |
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In normal individuals, breathing 100% O2 results in an ... of the PaO2. In individuals w/ physiological shunts, PaO2 levels ... to rise to that of normal individuals when 100% O2 is administered.
In individuals w/ physiological shunts, PaCO2 is .... This is in contrast to hypoventilation and diffusion impairment in which PaO2 is ... and PaCO2 is .... |
elevation
fail normal depressed increased |
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In an individual w/ physiological shunt, we will see ... O2, ... A-a gradient, and a ... partial pressure of arterial CO2
In an individual w/ diffusion impairment or hypoventilation, partial pressure of arterial oxygen goes .... -W/ diffusion barrier, A-a gradient .... -In hypoventilation, A-a gradient .... -w/ both hypoventilation and diffusion impairment, the partial pressure of carbon dioxide will go .... |
low
increased normal to low down increases stays normal up |
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Which of the following pulmonary functions tests can be used to distinguish between obstructive and restrictive disorders?
a. flow-volume loops b. pressure-volume curves c. volume-time curves d. all of the above e. none of the above |
d. all of the above
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Assume the pt. has emphysema:
Compared to a normal healthy individual, our patient has a _____ lung compliance and a _____ residual volume. a. higher – higher b. higher – lower c. lower – higher d. lower – lower |
a. higher – higher
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What is the most accurate way to measure our patient’s (w/ emphysema) physiological dead space?
a. Bohr’s Equation b. helium dilution c. nitrogen washout d. whole body plethysmograph e. multiply tidal volume by 30% |
a. Bohr’s equation
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What best determines FRC? (not dead space)
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whole body plethysmograph
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You conduct a PFT of a pt w/ emphysema. The MOST significant diagnostic finding of this test is:
a. increased FEF 25-75% b. decreased FEV1/FVC c. increased FEV1 d. decreased FVC |
b. decreased FEV1/FVC
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From a pressure-volume curve of our pt’s lungs (w/ emphysema), you expect to find:
a. increased work attributed to compliance b. increased work attributed to tissue resistance c. increased work attributed to airway resistance d. decreased work attributed to active expiration |
c. increased work attributed to airway resistance
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Which of the following conditions would you expect to find in a pt w/ emphysema?
a. decreased FRC b. increased recoil of the lungs c. decreased alveolar surface area d. decreased physiological dead space |
c. decreased alveolar surface area
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