When I wrote my "anesthetically-inclined" review of the 1978 movie Coma, I figured that Hollywood was extrapolating reality.

Anesthesia Flix Fix: Episode One - Movies that every anesthesia enthusiast should be familiar with...

After all, things like key-index and pin-index systems, O2/N2O fail-safe mechanisms, floating-bobbin flowmeters, drop down ventilator bellows -- all of these things and more had already made it into the practice of modern anesthesia to prevent the delivery of hypoxic mixtures to patients. Additionally, mass spectrometry gas analyzing systems were available to measure exhaled gases.

In these modern times, no one would suspect that the switching of nitrous and oxygen pipeline supplies would be possible...and furthermore go unnoticed for any significant period of time.

Unfortunately that very thing can and did happen

We often disregard things proximal to our anesthesia machines. I can't even tell you when I last did a real machine check. And today's anesthesia machines are much more of a black box than yesterday's Narkomeds, etc. This is just a reminder that our vigilance must extend even to the unlikeliest of scenarios.