Reza

But we very rarely spend time on the opposite problem, which is how can you be hypoxemic without dyspnea?

How can you have low oxygen going to your brain and you not be like, hey, I need help?

And I find that to be fascinating.

And I think fundamentally, it really emphasizes the idea that there are specific receptors in our heart and our lungs that tell us that we're short of breath.

And for me, I'm inclined to really study the absence of that to help make progress.

And I think it's almost impossible for me to foresee a scenario where somebody has an alveoli full of material that doesn't tickle those receptors and tell the patient, hey, there's something wrong.

And so I think not only is the exam...

an argument that the alveoli are not filled, the lack of a perception that there's a problem is really, really powerful.

And the reason I'm sharing all this now is because I think it might influence what I would do in the moment with regards to the BiPAP.

And so if we take Proff-Rez's hypothesis further and say, hey, you know, I'm really suspicious of a vascular cause here.

And the reason I'm suspicious of it just for completeness sake is the patient's not feeling the shortness of breath, so the alveoli are unlikely to be tickled.

Their lung exam is completely unremarkable.

And so you ask yourself, are you dealing with the vessels that are perfusing the lungs, namely the pulmonary capillaries or the pulmonary artery, or are you dealing with something wrong with the heart itself and that there might be a right to left shunt?

And it's premature to start to speculate on this because it's not an actionable hypothesis in most instances.

But let's remember that BiPAP isn't harmless.

And whenever you're choosing to install positive pressure into the chest, you worsen conditions that are pressure dependent.

So if somebody has a pneumothorax and that's why they're hypoxemic, you want to be careful about putting on BiPAP.

That thankfully isn't the case with the normal symmetric breath sounds.

But if somebody has a right-sided condition that is pressure-dependent, you want to be very careful about BiPAP.

And the most common pressure-dependent condition on the right side is pulmonary hypertension, which is not a consideration we have evidence for here.