Comments on: Alveolar Gas Equation for the USMLE Step 1? Diuretics? You Probably Won’t Guess the Connection.

By: Mashhood Arif

Mashhood Arif — Sun, 18 Aug 2019 18:44:53 +0000

In reply to Yousmle. deadspace is ventilation without perfusion no ?

By: Yousmle

Yousmle — Sun, 14 Aug 2016 00:45:00 +0000

In reply to oluwatosin ayanjoke. Physiologic dead-space is where blood reaches an alveolus that is poorly-/un-ventilated. You have hypoxic pulmonary vasoconstriction which helps to avoid this phenomenon, however when you give someone supplemental oxygen, you cause an increase in blood going to poorly ventilated areas → physiologic dead-space ↑.

By: oluwatosin ayanjoke

oluwatosin ayanjoke — Sat, 13 Aug 2016 17:20:00 +0000

Hi, Alec. Thanks to responses. I came across a question in uworld, but I do not understand the explanation given, i would really appreciate it if you could explain to me.
In uworld, it says that hyperoxia leads to hypercapnia, one of the explanations given is that hyperoxia causes vasodilation, which I agree with, and vasodilation leads to increase physiological dead space-this I do not understand.

By: oluwatosin ayanjoke

oluwatosin ayanjoke — Sun, 07 Aug 2016 00:56:00 +0000

oh, thanks i understand. its the CO2 in the venous system that is increased because of the CO2 from the tissues.

By: Yousmle

Yousmle — Sun, 07 Aug 2016 00:48:00 +0000

In reply to oluwatosin ayanjoke. Those are equivalent. There should not be a gradient between PACO2 and PaCO2 unless there is perfusion defect.

By: oluwatosin ayanjoke

oluwatosin ayanjoke — Sun, 07 Aug 2016 00:40:00 +0000

I think you should check the formula of alveolar O2 because in FA,its PaCO2 not PACO2