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I have a battery powered Ambulatory recorder connected to a Desk Top PC - What is the best way to perform an elctrical safety check without damaging the Desk Top hard disk
The safety tester I use is a Metron QA80.

Thanks in advance.

What, exactly, are you trying to "safety test" there ... a battery powered data logger, with ECG leads attached? Have I got that right?

Or are you thinking of having a go at the PC? If so, why? Is it not simply used "back in the office", as it were?

I think we need more information here about what it is you're trying to do.

Geoff,

Its an ambulatory recorder which is used to measure bladder pressure. The recorder is connected to the PC via an RS232 cable.
This setup is used in the operating theatre. I need to carry out an electrical safety check on the "system" as it were.
Hope this info helps.

As Geoff says...a little more information would help.

Normally of course, ambulatory recorders are stand alone while connected to the patient. After being disconnected from the patient, they are 'read' by a PC etc.

You say the device is used in theatre. Is the patient connected to the recorder while the recorder is connected to the PC AT ANY TIME?

Is this a standard PC? If so, what's it doing in an operating theatre? Get it out of there and into a side room ... then consider it for what it is ... a piece of office equipment!

Next question, please.

It does not matter where the PC is located if it is connected to a medical device. The lectrik runs down the wire!
I would run a touch voltage check with the kit set up in whatever is the normal configuration.

Yes, the lectrik runs down the wire ... but where does it run to if there's no patient at the end of it?

Surely in this case the actual "medical device" is used in ambulatory mode to collect data, and then the thing is brought to the PC (that is, without the patient tagging along) for the data to be downloaded. Of course, I may very well have misunderstood the whole thing. But I can't really see why the PC needs to be in the operating theatre, and I would always argue that the environment that the kit is used in is, in fact, the prime consideration.

As we all know, there are lots of PC's around in what could be regarded as "patient areas" these days (outpatients clinics being an obvious example that springs to mind), but whether they are "patient connected" is debatable in most cases. What standards (of electrical safety) are these PC's built to (or are they exactly the same as those for sale in PC World)? And ... what do the equipment suppliers (and their literature) say about it all (if anything), I wonder?

Anyway ... what's your answer to Sav's original question, then, Brian?

You are quite correct, if the PC is not connected to any patient connected device, then it is not a problem, but in many cases a PC is used to store data or display results when the medical device is in contact with the patient. The PC can comply with the relevent standards, but may also be interconnected to a number of other devices, monitors, hard drives, printers, and any number of other bits of kit, which all meet their own standards, but which taken together, can pose a significant risk. It is not unusual to find a PC plugged into an extension mains lead which is also feeding a monitor, printer, phone charger, and hard drive, so that the total earth leakage current flowing down the earth of the extension mains lead exceeds the maximum 3.5mA for a 13A plug.
If the PC is connected to a medical device that is in contact with the patient, then there should be an isolator in the connecting lead. In any case, I would check that there is no significant voltage (<10mV) on the medical device when it is connected to the PC, by measuring between all accessible conductive surfaces on the device and earth. Use a DMM and switch between AC and DC.You can sometimes get a DC touch voltage because the AC is being rectified.
On the same tack my report on switch mode power supplied has now been published, you can find it on
http://www.mhra.gov.uk/Safetyinformation...sSMPS/index.htm

Sav

Im sure the standard for PCs say that they only require safety testing every 5 years. If the PC is classed as a medical device then it requires testing as one, we use a Rigel 266+ to test them, as you can manually turn the power on/off. This allows us to boot up the computer with the power on, take a reading, shut it down, change to next test etc.

Just to point out that its not unusual for operating to have PC's in them for docs/consultants to view records, X-Rays etc.

Regards

Alan

Brian. Thanks for that link. Good work (I'll have a look at it later).

Alan. Yes there may well be PC's in operating theatres. But are they standard ones, or special (filtered power supplies, or whatever)? Are they nicely mounted on appropriate carts complete with isolating transformers? Are they (to use that phrase again) "medical grade" - in terms of ruggedness, protection against fluid ingress etc.?

Are they "patient connected"? Are they in any of the various "patient risk zones" (which vary according to whichever code you are following) - but basically mean "close to the patient" and/or anaesthetic vapours? And (finally) which code do you follow when you Rigel* them (and what does the technical documentation and equipment markings suggest) ... and what kind of results do you obtain? Phew! (and where is John Backes when you need him?).

(see also this recent post)

* Other electrical safety testers are available.