@Dustcap:- Yes, there are a fair number of "academic biomeds" about (although mainly in the States, from what I've seen). Plenty of learned papers written, and so forth. In days gone by, I used to read them.
My recollection is that, regardless of the criteria being presented, and the (often tortuous) formulae being devised, the same equipment types generally always came out "on top" of the Risk Level heap. These tended to be the same equipment types that any first-year biomed tech would have offered up if questioned. In other words:-
Defibs, Infusion Devices, Ventilators and Dialysis Units were deemed "High Risk" whilst Electrosurgical Units and Anaesthesia Units (amongst others) were deemed "Medium". Most of what we used to call "Electromedical" equipment (including x-ray) were awarded "Low" risk status (and quite rightly, too).
In one well-known paper from yesteryear:-
Risk (Hazard) Score = Qty of Eqpt x Severity x Freq of Mishap
Where "Severity" is the only questionable factor, and was meant to indicate "severity - to the patient - in case of mishap".
In a typical hospital, the overall results would come out something like:-
Infusion Devices Qty 40 x Sev 10 x Freq 3 : Risk = 1200
Ventilators Qty 20 x Sev 10 x Freq 3 : Risk = 600
Defibrillators Qty 15 x Sev 10 x Freq 3 : Risk = 450
Monitoring Equipment Qty 50 x Sev 5 x Freq 1 : Risk = 250
Dialysis Units Qty 8 x Sev 10 x Freq 2 : Risk = 160
Electrosurgical Units Qty 8 x Sev 5 x Freq 2 : Risk = 120
Anaesthesia Units Qty 10 x Sev 5 x Freq 2 : Risk = 100
Baby Incubators Qty 20 x Sev 5 x Freq 1 : Risk = 100
Pacemakers Qty 4 x Sev 10 x Freq 2 : Risk = 80
Muscle Stimulators Qty 4 x Sev 5 x Freq 2 : Risk = 40
SW/MW Therapy Qty 4 x Sev 5 x Freq 2 : Risk = 40
Radiant Warmers Qty 6 x Sev 5 x Freq 1 : Risk = 30
X-Ray Equipment Qty 10 x Sev 1 x Freq 1 : Risk = 10
Ultrasound Therapy Qty 2 x Sev 1 x Freq 1 : Risk = 2
Notice the interesting (?) case where Monitoring Equipment (although of Low risk - low severity - individually) is bumped up the overall list by the quantities involved.
In terms of Severity, Infusion Devices (poisoning), Ventilators (asphyxia), Defibs (electrical) and Dialysis (poisoning) (and Pacemakers - easily overlooked) carry the highest scores.
You're right about Anaesthesia Units, of course: severity of outcome is mitigated against by the constant attention of a skilled and experience operator. Contrast this with how Infusion Devices are used, for example.
