Anesthesia Ventilator Machine questions

Hello elsmar forum,

in my new company we are developing a new anesthesia ventilator.
This machine is able to mix anesthesia gases, O2, N2O and Xenon together and vent it into the lung of the patient. The intended use includes an anesthetist standing near the machine all the time.
We have got a 17 inch display for command input and information output i.e. Gas concentrations, pressures, flows and the like.

The acting part of the machine consists of embedded devices and ist split into modules like: ventilation, gas mixer, alarm output, measurement devices etc.. I am responsible here for Hard/Software Development and
the conformance of development process and documentation.

The Riskmanagement Process states that there are no injuries to the patient are possible. So they started here the development of the whole
software with a classification A (IEC 62304).

My experiences in this field are small. I have developed a low risk device Class 2b/Software Class A and did the certification process earlier. Because this company had only experiences in development of medical gasmixing valves and indeed started with the development a PEMS without getting experienced developers into the company, I have
my debts about all this.
It would be very fine if the one or another could post their opinion here.

Florian Hillen

The Riskmanagement Process states that there are no injuries to the patient are possible.

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This is totally weird, I?ve never seem an equipment that works with anesthetic gases that cannot harm the patient, besides, they are also life-supporting too. So, the first thing I would suggest is revising the risk management to verify if there?s really no problem.

With this in mind, you may change the software classification. Anyway, it?s a good practice (even defined in the amendment of IEC 62304) to first classify as class C if you are not sure of the classification, and only then going back to class A.

I have been a little unclear in my first post. There are risks, but those risks have been reduced by hardware protection, so the software can be classified with class A.

The requirement from IEC 80601-2-13 is that "Ventilation control, gas mixture control, and vapour delivery software items of pess without an independent risk control measure shall be considered as software safety Class*C.".

So you mean you have independent risk control measures that control risk for everything?

>So you mean you have independent risk control measures that control risk for everything?
>That means, that for Software has been done a separte Riskmanagement Process or that every Risk has been stated?

That would mean a wrong value on the Display can not produce unacceptible Risks?

>So you mean you have independent risk control measures that control risk for everything?
>That means, that for Software has been done a separte Riskmanagement Process or that every Risk has been stated?

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Well, you do need to perform a "separate" risk management for softwares failures, if software failures were not addresses in the general risk management.

That would mean a wrong value on the Display can not produce unacceptible Risks?

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No, it means that a software failure (which is part of the sequence of events leading to a hazardous situation) cannot lead to a hazardous situation that cannot lead to unacceptable risk.

Many Thanks for your help.

Regards
Florian Hillen