There's two problems with airgapping. First, how does the machine get updates? Do you mail a DVD to the anesthesia techs? Do they know how to install such a thing, or are they going to mess up the machine in the attempt? Or do you roll a service tech in a truck - to all the machines installed worldwide? (Yes, I know, if the alternative to rolling trucks is letting J Random Hacker play with your machine while it's keeping a patient alive, you'd better roll trucks. But updates are one reason why stuff winds up connected to the net rather than airgapped.)

The second reason why stuff is not airgapped is that it almost certainly connects to the hospital's patient records system. They have to keep a record of everything that happened until all potential lawsuits time out. Just in case there are complications from the surgery, they need all the records from the anesthesia machine uploaded after every use. So the anesthesia machine has to be on the same network as the patient records system - and so does every other medical device in the entire hospital. That network should be completely isolated from outside, but to do so, you have to airgap the network, not just one machine. Yes, it should be done, but that's harder to do, and harder to maintain.

For that matter, I've wondered, when you visit someone in the hospital, if you plug your laptop into the ethernet jack in their room and start looking around, what do you see?