EBME Forums Forums Free discussion Out of Hours Technology Medical Device Usability and Human Error

Well, it's in terms not of the physical user interface but rather that they are the only infusion devices I have ever seen that work in mm/hr rather than ml/hr. Confusing? I think so. A trap for the unwary? certainly.

As to the use of a "tool" to change the settings, yes, a nail file or the cap from a Bic Biro will do just fine

Bearing in mind that I didn't actually design the thing myself, I would say that it is "proven", if only by it's sheer length of service (what is is now ... forty years) and almost universal acceptance (or should that be, uptake in the absence of any serious competition*)!

It works in "mm" (rather than, I presume "ml") because that was about all the technology of the late 1960's allowed. It was designed by Pye - remember them? It also happened to the first (ambulatory syringe driver)! Not to mention cheap ... due to the use of components readily available at the time. Like micro-switches (no LED's back then)!

Confusing? To today's harried nurses, perhaps. Maybe nurses of yesteryear had a bit more time to actually think. Who knows? They didn't have degrees back then, after all.

They are not complicated at all. In fact the word "simple" comes to mind. Also reliable. And (I would assert) appropriate to the setting(s) in which they are used. And ... the adjusting screws could easily be covered if need be (by a bit of surgical tape - the nurses' favourite - for example) - not to mention the syringe cover itself.

Meanwhile, I believe I have mentioned elsewhere the nonsense of testing ancient technology like this to standards way beyond the original design spec (as I have seen happening to MS16A's in certain NHS biomed shops). And that goes for the design itself as well. That's a bit like condemning the original Morris Mini after taking a look at a modern "BMW" Mini (a bad example, perhaps - because the 1959 design was actually superior)! Oh yes, the "retrospectoscope" can come in very handy at times like this!

Sorry Dave. Like it or lump it, the MS16A/MS28 has already gone down in history as a classic design (of medical equipment). Hey, I've already got them in my museum!

* Until recently, that is.

Seems to me here Geoff, that you are making "points of argument" against points I never made in the first place.



Can't remember ever saying it was not "proven" only that the "device usability" was less than first class.



Well, there you are, we are talking about "usability and human error" after all.




I never said they were.



Never said it wasn't a classic just an example of poor usability and prone to human error (? the worlds most dangerous infusion device)

If we can agree that the word "quality" can be taken to mean "meeting the users requirements in all respects" ... then I would submit that the MS16A/MS28 is (or, rather, was) a Quality Design! High marks for usability, then.

Whether or not nurses cannot be arsed to use them *correctly, get themselves trained, ask a "senior" ... or whatever, is, I grant you, an "issue". But it is one that goes across the board (that is, may very well apply to any piece of medical kit), I would have thought.

OK ... let's move on to the next exhibit!

* Especially after all this time, the amount of controversy surrounding the device, etc., etc.

No where near, you should have seen (or investigated) the Vickers VP55 syringe driver.

The MS16/26 syringe drivers are brilliant they are simple, can be used regardless of syringe make or size, do not have pressure alarms (that only really let you know that you have a problem with the pipe work between the pump and the patient), or the myriad of additional features that are rarely if ever used.

Staff not trained on this or any other medical device should not be using that device.

Most if not all of the errors I’ve seen with these devices are human errors, you can not totally stop human error no matter what design you come up with.

I am afraid that in my experience as the design of equipment has improved (safety wise) it appears that the users become lazier or less vigilant.

Lee

What we need are more MS16-type infusion pumps ... but big 'uns! Ha, ha.

But somehow I guess that's not the answer Dominic is looking for. He has a six-year project, after all!

Have you looked at the "Design..." .pdf yet, Lee? Quite interesting, I reckon. Clearly laid out, too. A good "discussion document", in fact. So ... please discuss!

@ Lee, have never seen the Vickers VP55 (from the same people who brought you the Vimmey bomber presumably !!) so can't comment. Perhaps I should have said the the worlds most dangerous contemporary infusion device.

Do people become lazy/slack/dependent when technology is available to take out the thinking part, no argument from me. All the "safety nets" provided can remove the inherent checking that will happen with more basic systems but, frankly, that is a path that we are so far down we cannot, nor I think, should we turn back from. We are not yet at the end of that path, it's just that the bumps are still a bit "lumpy"

I am reminded by this discussion of a comment I heard from a "vehicle safety expert" some years ago when asked about air bag technology. His comment was that, even though air bags were a wonderful technology, in some ways he would much rather see a large steel spike attached to the steering wheel, pointed towards the drivers chest, that way, he said, people would be a lot more careful instead of feeling that they could/would not get hurt if things went wrong. I think he had a point (pardon the pun).

Indeed. Most old cars (British ones at least) generally had the steering column configured as a lance for that very purpose!

By the way, have the Aussies started making their own aeroplanes yet? Interested? Then take a look at the .pdf.**

Actually, there was nothing much wrong with Vickers Medical kit, in my opinion. Clean designs, rugged (that is, made of steel rather than plastic), reliable, and all the rest. Ideal, in fact for extended service throughout the Empire, and beyond.

And, I might add, still sought after for equipment* donations in the "tougher" parts of the world.

*Certain other British manufacturers deserve an honourable mention there as well. Eschmann, for instance. Even good old (but sadly long gone) Cardiac Recorders! And the famous SAM pumps by M.G. et al. Plus, of course, Blease, Penlon and the older Ohmeda stuff (BOC-Medishield, whatever). Plenty of examples of Good Design to be found amongst that lot!

**With the state the world is in now, one wonders if they could have followed that same route today.

Footnote: the Vickers Vimy was built in the Bedfordshire town of Leighton Buzzard ... not far from where I am right now!

Are the MS16A's the ones that people were getting confused - I recall someone saying that there were some incidents of mixing 1hr syringe drivers with 24hr syringe drivers... as per the warning on page 86 of the guide

We can say this confusion should never occur as people should be aware of the differences, be fully trained, have time to think and check everything they do and focus on what they're doing without interruption. However, it seems this utopia rarely exists, and in rare cases error gets through the safety checks and alarms and things go wrong. It's probably true that human error cannot be eliminated but there are things that can increase and decrease its likelihood. Human error is a term that is used broadly and sometimes people use it too readily to blame 'lazy' users when really the system and devices need to be thought about as well.
(From the perspective of our project we probably have a bias toward not blaming the user but trying to understand why the error happened (in terms of device design, cognition, and the context), often because other 'normal' people in the same situation would have done the same)

I must admit that converting between 'ml' and 'mm' sounds like a nightmare to me. I'm not sure what's involved at this stage - but my intuition is the less conversions and calculations the better. The volumetric devices that do most of the calculating for you seem friendlier. It'd be nice if the prescriptions included the exact information that is needed for the device to reduce the translations and calculations nurses have to do. I think this would reduce the likelihood of error.

There was an important point made about dumbing down work as the devices do things for you e.g. the calculations. Here we become more and more reliant on the technology... we're pretty stuck if the battery runs out on our mobile phones as we don't know the actual numbers any more, and I am sure more people get more lost when their SatNavs fail. However, this can also allow us to do more. A nurse raised the point with me that they do a lot more nowadays... when she started the max amount of infusions per patient was more like 2 or 3, in the most extreme case she had 15 pumps hooked up to a patient and was managing them on her own. Real consideration needs to be given to doing more, doing simpler, and deskilling people... you might make the system more efficient but it might be less resilient and more prone to error.

The issue of feeling safer and taking less care reminds me of people reducing visibility at roundabouts, i.e. they would plant hedges so as you approached a roundabout you were unable to see oncoming traffic, therefore you were more likely to actually stop. With better visibility people take more risk as they look ahead, anticipate and squeeze into the traffic. Ironically then the safer system is less usable, less efficient.... again careful consideration needs to be given here. It does emphasise thinking about the system holistically to make it safer.

James Reason has come up with a ' three bucket ' model which I think nurses are meant to use to be more aware of 'risk'. Basically the more proverbial in the buckets the riskier the situation and the greater need to back off, think and get help. (I'm not sure if there are plans to incorporate a fan into this model )

Yes, that's the one.

The MS16A and its famous friend the MS28 come in for a lot of flak. But, personally, I don't buy it.

These things are used in special settings (such as Palliative Care), and not - generally speaking - by every Tom, Dick and Harriet who happen to have nothing else on!

As the quote says, the real issue with those little pumps may not be the "difficulty" in recognising that they are designed to deliver a linear distance rather than volume, but the fact that they may simply be confused (that is, mm/hr versus mm/24hr versions). Which, of course, is a serious mistake to make. However, they are colour coded. How "dumbed down" does kit have to be?

What would prevent similar mistakes being made if the things were calibrated in ml?

Reason and his buckets? Interesting for some, perhaps (that is, those who like to spend a lot of time at training seminars and the like), but it sure looks like (yet another) box-ticking game to me (and designed for whingers, at that)! "Culture and power distance"? Eh?

Roundabouts? Yes, I consider them to be the most dangerous feature of the British road network. Take a look at the A1 ... much improved since many of the roundabouts have been eliminated. Surely I have mentioned before my campaign to introduce some kind of standardisation of roundabouts on British roads? Getting it all down to something like three or four (well-designed) types. Not to mention the complete removal of all so-called mini roundabouts! In that way, we could probably save many more lives than fiddling about with medical equipment (which has, on the whole, already been well designed).