John Lumic's wheelchair was used by its eponymous owner for life-support. Such features included a motion control lever, breathing apparatus, and an oxygen tank. Also incorporated were doses of medication which would be taken intravenously. (TV: Rise of the Cybermen)
After Mr Crane damaged the wheelchair's life-support systems, Lumic, judged by his Cybermen as being "in pain", was converted into the Cyber-Controller. (TV: The Age of Steel)