Did a patient on a ventalater in the 1980s breathe in filtered air from the machine? i coughed in hospital room and worry . he died 2 wks later. did ventilaters back then ,work like now?

Patients on ventilators in the 80's like now were given an oxygen blend at various concentrations with filtered air from a closed hospital grade system. They are not given air from their patient room. Your coughing in the room did not cause the patient to die. If they were on a ventilator they were already sick enough that this was a likely endpoint.