EBME Forums Forums Maintenance Technical Assistance Laptop computers in theatres?

Hi,
We are looking to obtain images (e.g from a camera stack) and store these on a laptop using a composite PCMCIA card.
Is there a reason / standard etc that I should be aware of before commencing this?
Thanks,
John

Hi John,

What are the interconnections between the PC I/O ports and the medical system and will the PC be connected to mains during use? If so how/where are the connections made? What does the stack consist of, i.e. what're its component parts, and how's it all connected?

Richard

If it is connected as part of a video stack 'system' it will need to comply with BS EN 60601-1-1. (I think?)

BS EN 60601-1-1:2001
Medical electrical equipment. General requirements for safety. Collateral standard. Safety requirements for medical electrical systems. Section 1.1 Collateral standard: Safety requirements for medical electrical systems

John

BS EN 60601-1-1:2001 has been superceded by BS EN 60601-1-1:2006

Basic aspects of BS EN 60601-1:2006 and BS EN 60601-1-1:2001 are a start. The PC will have to be compliant with its own safety standard, e.g. BS EN 60950-1:2006, and be CE marked if it's connected as part of a medical system via a functional connection, e.g. a composite video cable, and/or a shared mains supply, e.g. MPSO connected to the secondary winding of a separating transformer.

I'm not going to assume you are using a video stack that's compliant with 60601-1 or 60601-1-1, i.e. in terms of safety requirements. Depending upon whether the PC is used on the video stack in the patient environment, in the same room or another room depends upon what's required to connect it to the video-endoscopy system. If you have more details about it then I'm willing to help with more practical advice off forum if you like.

I'm not assuming anything, that's why I asked about the system connections, etc. The standards don't really tell you much unless you have some idea what you're trying to achieve in terms of electrical safety. YOU become the manufacturer of a medical system when you connect devices together - there are higher risks involved when connecting medical and non-medical devices together or you take advice that's flawed.

Alternatively there are always experts at the MHRA that you can speak to if you wish to find out what the safety requirements or implications of adding non-medical devices to medical systems are.

Richard

Surely it depends if there is already some sort of storage device on the stack (DVD recorder etc.). If so, then the saving to the laptop can be done later, out of harm's way. What's the actual set-up there, John?

Thats a good point. Alternatively the PC could be used on battery to avoid some problems with providing mains isolation but this isn't ideal, temporary and risky since operators can connect mains, etc. Not recommended.

You'd still need to ensure acceptable leakage currents i.e. "equivalent enclosure and patient leakage" from between conductive accessible parts of the internally powered PC to patient applied parts of the medical system and earth, etc.

Thanks so far chaps.
The stack is compliant with BS EN 60601-1-1:2006. We want to get away from video printers, etc.
The reason for connecting a separate laptop is so we can download the images on to the hospital network as IT have just invested in a terabyte server with a big partition for archiving images.

No existing storage device on the stack, then? How, and where, is the image collected, and ported to, I wonder (ie, where do you plan to connect to)? The camera controller? What connections are available at the back of that one? Dare I mention Bluetooth, Wi-Fi etc.? That way your laptop could be in the next room! I presume you want to save to the laptop for editing etc., or else why not download directly to the big bad server? This is interesting. Don't forget to let us know how you get (got) on, John.

If you connect to the network when the stack is in use, via a laptop online, then there is the potential issue of leakage currents being introduced by the network connection(s) under normal or single fault conditions (earth-loops?), irrespective of whether mains separation being used to supply the laptop PSU and the composite data is being acquired from a medical grade video processor.

How things are interconnected as a medical sytem is the issue - not just whether, as individual devices, they meet their respective standards.

Table BBB.201 in 60601-1-1 (Safety Requirements For Medical Systems) and reference to the rationales in the 3rd edition 60601-1 standard is useful when considering the combinations of medical electrical equipment and how they're connected RE: solutions to providing additional protection to medical systems.

Just because each individual interconnected devices meet their respective standards doesn't mean that the system necessarily meets safety requirements.