EBME Forums Forums Management Medical Equipment Management CTG batteries

I've been asked by a Midwife to find back up batteries for Hewlett Packard and Philips Cardiotocographs...Do such things exist or can't I use Google?

Why? confused:
If you have to, then you would have to purchase a UPS, but that would only provide you with a finite running time.

Don't these devices rely on an internal backup battery to retain clock settings/user preferences when the mains is disconnected? 1/2 AAs perhaps?

What model of HP / Philips CTG are we talking about here. We have three types of batteries for our HP CTGs

M1353A, has two AA batteries under the paper tray.

8040A, has an old Mercury battery which now been upgraded.

8041A, has two small LR1 batteries on the back panel.

Try www.combatalexander.co.uk get your batteries.

A.M

It turns out they are using a Philips 50 IP, a 50 AM and a couple of Oxfords: a Meridian 800 & a Sonicaid. To be clear they want back up batteries in case of power outage during procedure...our gennies have been known to fail on occasion.

Withnail

Check first, but I think you will find attaching a fetal monitor to an industrial UPS will exceed several electrical safety limits. You will therefore probably need to fit each monitor trolley with an isolation transformer, as commonly used with ultrasound scanner trolleys etc. Borrow one and give it a try in your workshop.

The usual procedure in these circumstances is for the midwife to go back to manually listening to the heart sounds until normal service is resumed and hand annotate the printout to that effect.

Marc

Hi Withnail,

My understanding is that any electrical device, specifically, connected to medical equipment that conforms to medical electrical safety standards as it should (60601-1) itself becomes part of the medical system - thus there's a requirement to meet additional collateral medical electrical system safety standards (60601-1-1).

This means that, for a class 1 (mains with protective earth) CTG system a medical-grade class 1 seperating transformer and appropriate mains distribution may be a requirement to limit system mains electrical leakage currents, with the UPS operating whilst connected to the CTG, to acceptable values when tested using a medical grade safety tester.

This may be necessary to limit the potential risks associated with micro and macro electric shock; in an attempt to ensure the safety of both patient and operators in the clinical environment. However the appropriate tests would need to be performed, either way, to assess the need, or to assess the effectiveness, of the seperating transformer and associated mains distribution.

I notice you're described as an equipment Nurse in your profile, rather than an Engineer or Technician working in Clinical Engineering so, given the potential for injury to possibly vulnerable patients' and their babies when modifying mains supplies and protective earthing connections (as you would do when fitting a UPS - due to scenarios that you may or may not be aware of), I'm just mentioning this in case you're not aware of the H&S implications, not to mention ethics of modifying patient-connected equipment without the necessary background knowledge or guidance.

I would ask myself, if I were in your position, "Am I aware of the potential safety implications and do I have the knowledge to fulfil my colleagues' request?" More importantly do you believe they are aware of the implications of what they're asking?

I know it seems trivial, especially to those who've connected UPS systems to their PCs at home, whatever, to fit a UPS to a CTG but your midwife colleagues need to be aware of the potential implications and seek appropriate advice, from those who are appropriately qualified and experienced, in my opinion.

EBME, Medical Physics and the CTG equipment manufacturers might be useful sources of advice - the first question I would ask of the CTG manufacturer is whether they would recommend the use of UPS systems on their CTGs and which ones they would recommend the use of, if they do.

Hope this helps.

Powervar in Swindon manufacture medical grade UPS conforming to the 60601-1 standard
tony.bell@powervar.co.uk will be able to assist you Im sure

Hi,

A useful contact that Darren.

Will they visit the hospital to install and electrically safety test the system to medical safety standards do you think? Just that seperation may not actually be required (this will need to be determined by safety testing with the UPS fitted, probably) and even then if seperation were fitted, anyhow, it is still possible that medical system safety may be compromised by the UPS/seperating transformer combo, e.g. earth-bond may be degraded, so safety testing to ensure compliance will still likely be necessary.

There's also the question of quality of the mains provided, e.g. suitability of mains waveform/harmonics, power requirements/specification, etc, and ongoing maintenance of the UPS. Any of these could affect system reliability - the introduction of a UPS system may actually reduce the overall reliability of the medical system , for example, when the batteries, fuses or the UPS electronics fail in normal use (if direct online UPS is used for example), extra buttons to press, etc, etc.

Things I've observed in practice when UPS systems are fitted to a variety of medical devices and the operators are not technically aware of the implications. The problem can only be compounded if those specifying and fitting the system are non-technical. Cost may be a driving factor as well....

I've found UPS systems can cause headaches due to these sort of things and that when you need them the batteries may not be up to it if the systems are not maintained - these are some of the other implications I was thinking of as well as the basic safety aspects. UPS systems are Ok for medical systems as long as they are properly specified, intially checked and maintained on a fairly regular basis plus the appropriate seperation is fitted, if required.

Thanks to all for the comprehensive options and implications...a lot to chew on. As a nurse I agree, Marcel, although unfortunately with the prevalance of technology old school techniques are in the decline, the younger staff (myself included)are, for the most part, only effective in a technology rich enviroment...hence my coming here for help!!
Mr Ling, thanks for the advice...I had hoped that some one would give me a product code for a generic battery pack and the number of a rep ( - typical nurse!)so I could sort this without bothering our technicians...although now I shall go to them with a much better understanding of the issues, which will in turn speed up the process.
Thanks again for all your time...