"The only way of discovering the limits of the possible is to venture a little way past them into the impossible." - Clark's Second Law
In prior posts here and on the Medical Evidence Blog (here, here, here, and here), I have outlined my position that the only way you can really know if a patient can breathe on their own is to let them try - a "trial of extubation". Prediction equations get you published, but their signal to noise ratio is often poor and ignored, to patients' peril. Indeed the reason I'm obsessed with extubation is because I think being intubated unnecessarily is one of the worst things a patient can endure, and the best thing I can do as an intensivist is identify the earliest moment when a patient can breathe on his own and extubate him.
I faced a very harrowing extubation decision recently, and I admitted to the medical students that it was the most nail-biting of my career. But I think analyzing it, both before and after the fact can be very instructive.