Is There a Good Threshold for Intubation?

PF ratio can be transformed into SPO2 or a FI2 ratio. The point is that the category at really high risk where your intubation threshold should be relatively early are patients who start with PF ratio below 150. And if the PF ratio goes down and you have to continuously increase FR2 and PIP, I think that's a good reason to intubate the patient.