I believe you need to involve your infection control people (person?), then leave matters to them.
Regarding any extra risk posed by Covid-19 ... I would say that would depend upon the nature of the surgical procedure being performed.
I would expect special attention to be paid to the patient tubing circuit (disposable would be best). I'm also wondering about soda lime in the absorber. Maybe that should get binned, as well.
Do you have *AGSS?
Old anaesthesia machines should be able to carry on indefinitely as long as they are properly maintained (and spare parts - if ever needed - remain available).
* Anaesthetic Gas Scavenging System
