42 肝硬化病患在肺臟可能會有如同皮膚spider angiomata的血管變形，在氣體交換的生理效應不會有何種表現？

肺泡二氧化碳分壓（PACO2）下降 肺泡氧氣分壓（PAO2）上昇

動脈血氧氣分壓（PaO2）下降 肺泡－動脈氧氣分壓差（PAO2-PaO2）下降

answer is D

understand this qusetion as this:

spiderangioma, blood pressure dilation secondary to pressure build up due to liver cirrhosis.

this question is not asking, liver cirrhosis in correlation to the lung, but is asking if such pathology of telangectasia happened in the lung, what will happen to the changes in PAO2 and PaO2?

thus, lets understand it like this: telangectasia in lung. destroying the normal gas exchange barrier in the lung.

thus, i will have less CO2 diffuse across to the alveolus: hence a decrease in CO2 in the alveolus.

the O2 in alveolus is also expected to increase, because less in crossing to the blood.

arterial O2 is also expected to go low , due to poor perfussion of O2 to reach the blood stream.

the last choice D/

alveolus / arterial O2 : alveolus goes up/ arterial O2 goes down = greater value!!!! hence increase!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!