EBME Forums Forums Maintenance Technical Assistance Cardio Call ECG recorder

We have a number of Spacelabs Cardio Call Memo instant ECG recorders. One, less than 12 months old has been back to Spacelabs twice for re-programming and SpaceLabs have suggested it may becoming corrupted due to mobile phone interference. I have spoken to them regarding this and am told it is being investigated. I wondered if anyone else had come across this issue?

The clinicians tell me the transmission of the recording is done via a landline not a mobile phone.

Mick

Ah yes, the ol' mobile phone, taxi transmitter, CB radio user excuse. Cobblers !

I have, over the last many many years had this type of excuse put forward for many problems involving RF/remote comms.

One of the things that needs to be remembered is that, once something is digitized it is actually very difficult to break that code up. There are things called "check sums" (and probably other things that have happened since I 'were a lad") that check the integrity of the data and if not correct then the system asks the other end to retransmit (this applies not just to IP systems but to digital comms in general).

What you have here, I suspect, is a problem that they cannot explain and are looking for an external "reason". Back to base principles I'm afraid.

Hi Dave

Thanks for your reply.

I agree with your theory, but really as Spacelabs are already investigating this problem it would appear that more than us are affected. So I wondered who and in what circumstances.

Mick

It is good that they are investigating and if they come up with anything I hope you will post the results here for all to see. So folks, anyone else have the same issue?

Ambulatory event recorders? Doesn't the data get transmitted first to a "base station" and then on again from there if need be (to storage, telephone line, whatever)?

If it is only one of a number of units that is always playing up, then logic surely dictates a problem with that unit. Or, more likely, I would have thought, the circumstances surrounding that unit (the environment it lives in, for example).

How (what technology) does the thing use? What distances are involved? Could the operating frequency be anywhere near that of the microwave oven, etc.?

What is the nature of the actual problem, I wonder? Corrupted memory or simply a poor ECG recording? Could it just be the electrodes? More information needed!

Hi Geoff

It is a recorder the patient places over the heart and presses a button to record an event or perceived event. The problem presented was the unit's LED's flashed accompanied by a continuos tone. Spacelabs re-program the EPROM.

Mick

LED's flashing and irritating noises to indicate a fault, I presume.

I wonder what actually triggers that condition. My own guess would be nothing at all to do with EPROM's (why should it become corrupted?) ... and more likely something else. Like "event not accepted" for some reason or another.

Or, much more likely perhaps ... a duff battery (or contacts)!

Am I right in assuming that the patient is "out" somewhere (away from the hospital), at home perhaps?

Meanwhile, have you been able to take a close look at the thing yourself?

Geoff

The monitor is still under warranty and has been returned for a second time for the same fault. The manufacturer have re-programmed the EPROM and that seems to rectify the fault. Being a diligent sort, I have enquired as to the likely cause of this fault and have been told it may be due to mobile phone interference. This is only a theory and is currently being investigated.

As I said above my question is has anyone else had the same trouble. If it is a major problem then we all need to know. If the problem, however unlikely is mobile phone/microwave/wireless internet/comic relief/royal wedding (delete as appropriate) related then Space Labs need to address the problem with some urgency.

The device is indeed used in the community.

Mick

Fair enough. And I suppose that the patient is currently using another unit of the same type. So we now await the next "event" (or, in this case, and as we all hope - "non-event")!

Meanwhile, I agree:- how about suggesting that someone (from Spacelabs, perhaps) visits the patient in order to survey the immediate environment? Who knows, the patient could be a radio ham or some such thing!