respy Qs

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respy Qs

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3 Posts

Luckyall
Forum Guru

Topics: 11
Posts: 592

01/23/07 - 01:28 PM

68 y/o man with a long h/o heavy cigarette smoking demonstrates a typical obstructive pattern during pulmon. function testing. His main probl was emphysema wich recently lead to Chronic hypoxemia.Supplemental O2 given to this pt. would be expected to produce wich of following?

PAO2 PO2 A-a PaO2 Lung didusion capacity

A) increase decrease increase increase
B) incr decr incr Not changed
c) incr incr incr not changed
D) decr incr incr incr
E) not changed not changed not changed not changed

Palaniappan
Forum Senior

Topics: 30
Posts: 148

01/23/07 - 01:45 PM

C...?

Luckyall
Forum Guru

Topics: 11
Posts: 592

01/23/07 - 03:40 PM

Supplemental O2 will always increase PAO2 regardless disease process---> that means there will be an incr in O2 gradient across pulmonary mb system---> accelerating rate of O2 diffusion. This will NOT add a significant amount of O2 to blood leaving lung regions that equilibrated with alveoli before giving O2, but will ADD signif.O2 to the blood in regions that previously failed to reach equilibrium, or in poorly ventilated regions where PAO2 was low.
Even so the increase in PAO2 will be greater > then the increase in PaO2--->increse in (A-a) grad.
Diffusion capacity of lung is a measure of ability of membrane system to transport gas @a given gradient. This depends on surface area & mb thickness. Giving supplem. O2 DOES NOT alter the mb charact of the lung

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