Do iron lungs still exist?

I'm supposed to be doing some work this weekend, so displacement activities are becoming attractive. It occurred to me that I hadn't seen or heard anything about iron lungs for some time, and in the circumstances it was imperative to find out about them right away.

An iron lung is a negative pressure ventilator that allows patients who are unable to breathe for themselves to breathe. The body is placed in a sealed tube and the air pressure is alternately reduced and increased, forcing the chest to expand and contract. They filled hospital wards in the 1950s and 1960s, when polio was common. The unluckier polio victims ended up with paralysed diaphragms, and only the iron lung, invented in 1928, kept them alive. I remember seeing references to them even in the 1970s, when new infections of polio had been eradicated in the UK. It seemed a hideous fate, to be encased for ever in a noisy tin can.

But technology had moved on by then. Positive pressure ventilation by intubation became standard procedure, and portable negative pressure ventilators were invented.

But they still exist and are very occasionally used: see this BBC article and this Wikipedia entry.