I think it's time to pull together some earlier threads under a fresh banner. Following debate (in those earlier threads), some consensus has emerged regarding a need to afford techs some flexibility in setting (and adjusting) PM intervals.

Briefly, the idea is to consider adjusting PM intervals (lengthening usually, but can also be reducing) in accordance with risk criteria (the factors for which need careful consideration) and the passage of time (with experience of the actual usage of the equipment, its continuing condition, reliability and failure patterns, and other such indications).

The aim being efficiency in the best use of technical man-power (limited, in every case that I have ever come across), addressing all equipment on inventory, with emphasis on patient safety, whilst still encompassing the well-tried principles of equipment maintenance, in all its guises.

Some of those earlier threads were "left hanging", as it were. So let's see if we can draw things to a tidy conclusion this time! These are the earlier threads:-

1) One
2) Two
3) Three
4) Four
5) Five
6) Six

... OK, let's continue from here ... !

I hope I may be forgiven for quoting from my own post, but it seems to belong here (at this juncture):-


See also Paul's response. Any chance of some more comments from you (Paul) regarding this topic? How about some links?

Note that "Ridgway excludes non-critical devices, and any for which there is no evidence of benefit from PM". Here Malcolm and I must disagree, I'm afraid. Or, put another way, I have yet to be convinced, especially on the first point. And surely the second point can be challenged on what exactly is meant by "evidence" in this context. For instance, it could simply mean that the PM procedure, and its interval, is in fact "spot-on"!

I have always been very much of the old-school "go to the department and PM everything you find" approach! It is (was) known as the "Sweep Method", I believe, but probably does not get used much these days!

Finally (for now, at least) here's some more background reading.

Before someone comes on here again insisting that Risk-based PM is all nonsense, and that everyone is obliged to blindly follow whatever PM interval (and procedure) the manufacturer recommends in each case, here is "chapter and verse" from DB-2006(05) (which, as far as I am aware, contains the current equipment management "guidelines" issued by the MHRA ... that is, an Agency of British government):-

Under Section 8.4 (Planned Preventive Maintenance). Note against Service Interval ...


So doesn't that simple phrase "taking into account how much the equipment will be used" open the door to lengthening the PM interval beyond that recommended by the manufacturer, as long as agreed conditions are met, and documented?

By the way (and in my opinion) DB-2006(05) contains a whole load of common-sense, well-reasoned "policy statements"* (and not before time, I might add), and I hope and assume that, by now, all government hospitals and others responsible for maintenance and support of medical equipment follow its guidance. To my mind, the only trouble with "guidelines" like these is that (just like the Highway Code) they are not actually made compulsory by Law!

* Like, for example, permitting spare parts to be sourced from alternative suppliers as long as they are to "the same specification" and that sourcing decisions are properly "risk assessed, costed and documented". Happily, it also reminds us of the legal basis for carrying out electrical safety testing (EWR under the HASAWA). But unfortunately, it is a bit vague about just when (and to which Standard) these should actually be carried out. Let's hope that the next issue of such "guidelines" is able to endorse IEC-62353, and be done with it!

Here's some more related posts from the hallowed archives, especially with regards to Risk Criteria and Scoring.

Litera scripta manet!

And here's yet another "blast from the past" which touches on PM intervals. It has been kindly pointed out to me, and I note that it originates from well before I first joined in the fun here on the forum (back in the Good Old Days, then)!

The guys made some interesting points. Has anything changed, nine years on?

Hello Geoff,

Another link in the same vein:

Reliability Centred Maintenance (RCM)
After being created by the commercial aviation industry, RCM was adopted by the U.S. military (beginning in the mid-1970s) and by the U.S. commercial nuclear power industry (in the 1980s). It began to enter other commercial industries and fields in the early 1990s.
see: http://www.ebme.co.uk/arts/rcm/index.htm

Yes John ... I know you are a "true believer" in the concept.

Do you have anything to add to the current thread? Have you, for instance, had any joy in implementing RCM over the last few years? And how to sell the thing, and convince "the Management" of the need for it?

Good topic that requires study & reflection, neither of which I have time for at the moment so forgive me if this article has already been addressed. In the Health Estate Journal May 2006 Vol 60 No 5 Paul Robbins wrote about managing risk in device engineering - here's a link to it but the web online article doesn't have the figures & charts so try & get your hands on the original - http://www.healthestatejournal.com/Story.aspx?Story=1063.

Identifying, categorising and scoring risk is addressed and it is topical for those of us in the NHS because the regime of payments by results should give priority to mission critical devices and systems.

Must try and catch up.

That's a great link, Paul, and thanks for adding it to the pile, as it were. I for one hadn't seen that before, and I look forward to going through it later.

Many of us are aware that a few (perhaps more) people "out there" are actively pursuing the kind of practices we like to talk about here, but we don't always get to hear much about what they are up to, unfortunately.

I may as well make this little plug:- contributions (that is, posts) to this forum cost nothing (except a few minutes - usually - of anyone's time). But the missive then gets a viewing, and an airing, all across the world. It also gets published, shall we say, instantly, and presents itself (literally in open forum) for immediate comment, feedback, and ... er, rebuttal.

A form of true democracy, then, in the proper biomed style (that is, peer review ... usually with a bit of banter thrown in).

On the other hand, "learned societies and institutes* ... " (I'll leave you all to draw your own conclusions).

* Needless to say (and as mentioned before) I personally ditched all that stuff (and all those subscriptions) many years ago. I can't see what's wrong with the free exchange of information, as practised by many on this forum.

After-note:- having just gone through Paul Robbins' excellent paper ... yes, it would be nice to see the illustrations. Especially Figure 7 (if nothing else). Another thought that I picked up was this one (to paraphrase):-

Perhaps it's the user that needs maintenance, rather than the device! Yes, indeed. And this is, I would suggest, the perspective from which to look at hospital-based equipment maintenance, anyway. That is, from the point of view of the needs of the user, and are these needs being met?

Dave’s basic principle: That no reduction of safety or reliability be done (much like the Hippocratic Oath really!) but that the requirement for assessment, testing and preventative maintenance of equipment be assessed on the actual, evidence based, and provable requirement for that testing/assessment/maintenance. That, the OEMs requirements are NOT the bottom line but, rather, the application of a full risk analysis can better provide an effective system of PM schedules.

I would hope that those who are going to enter into this conversation have a understanding of the principles of risk management and/or have read and understood the various standards that apply (here in Oz that’s AS/NZS 4360:2004 but in other parts of the world other, but similar will apply, me thinks.) The principle is the same no matter what.

I would have to say at this point that I am deeply indebted to the folk at The Ottawa Hospital for their generosity in sharing their work on risk based systems with me and, I hope they don’t mind, via this forum with the world.

First, I would draw your attention to the file attached (Leo-Risk Based PM Scheduling.pdf). It is through this that I first became aware of the work in Canada. This gives a good general impression of the work that was done there. Second, have a look at the detail of the Risk Form shown. This shows the basic format of the assessment as done. (assesment form.pdf).

If we run an example of this (and for this I will use a Datex Tuffsat Spo2 monitor) then the results pan out as..

Function rating: Patient monitoring device: 5
Consiquence rating: mistreatment 3
Maintenance rating: None 0
Protection rating: Yes (3), No (6) 6
Failure rating: none 0
Use & availability daily 6

Total score 20

This score would then place the Tuffsat into a once per year PM category.

Now, I have to say that I think that this is an incorrect assessment and as such I would (and intend to) modify the scoring system. My reasoning is that, although this is a patient monitoring device it is not used in high acuity monitoring but rather in low risk ward type environments. This should reduce the score under the “Function” section. Similarly, under the “Consequence” section, in theory a false (low) reading could lead to treatment of a condition that is not real but in the ward type environments that this devise is used is that actually the likely outcome? I think not, so again, perhaps some modification would be required to lower the risk score here.

I have intentionally used the Tuffsat as the example because my feeling is that such a device need never be tested (I can hear the gasps of disbelief from half a world away). It is a hand held, battery operated device. It has no calibration or adjustment. In short, it works or it does not. The only problems I have seen are of the probe or the complete shutdown of the unit. What do we achieve by doing an annual PM? Answer, nothing. I would put this type of device into a “check function only on repair” category.

“But what about performance verification?” I hear some cry, to which I would answer, why? what’s the point? A performance verification is valid only at the time it is done and becomes invalid as soon as the device is moved/used/etc. If we are to provide a true verification then it would need to be done before every use. To do so once per year is, I think, a complete waste of time.

At the other end of the scale of course are those critical devices such as ventilators, anaesthetic machines, defibs, etc. A quick check on an ICU vent, for me, scores a 46 (that’s 12,12,12,0,6,4 going down the check sheet). This quite rightly shows a requirement of 6 monthly PM. I have no argument with this requirement.

So, pros and cons……

Pro..

A risk based approach to PM can provide for continuing levels of equipment reliability and safety while reducing the resource needed to support this level of “up time”.

We are all aware of the increasing levels of equipment use within the healthcare sector but are also aware that there has not necessarily been an increase in the funding or staff levels in BME departments to match it. Risk based PM provides a way to use the available resources in a more efficient way, focusing the available resources where they are needed and away from areas they are not.

Con..

Risk based PM may actually reduce the resource requirement to such an extent that some staff are no longer required and budgets may be reduced or the level of income to the department will drop.

Well, yes, potentially, but is that a bad thing? We all, both in the public and private sectors, have a responsibility to those who fund us to provide best value. Risk based PM provides a channel by which this can be done. To take a Sir Humphrey Appleby like attitude of “the more staff we have the more important we are” is not reasonable in today’s environment. The tax payer (and that is you after all) does not have endlessly deep pockets. We all need to look for efficiencies in what we do.

Couple of other observations.

I took the form shown here down to one of our client hospitals to try them out and sat down with the nurse unit manager of ICU/CCU. I found that we had somewhat differing views in some areas. One of the examples used was the 12 lead ECG machine that lives in the unit. It was clear from the discussions that the NUM that she viewed the function of that ECG machine as absolutely critical to the running of the clinical unit. I did not share this view. This is not the only ECG machine available (there was another in a ward just round the corner) and the monitoring system used in the unit had 12 lead capabilities as well. To my way of thinking, these were viable alternatives in the event of a breakdown she however saw only that clinical practice required that a conventional ECG machine must be available in the unit at all times. My point here is two fold. First, some measure of the clinical practices should/needs to be taken into account when doing a risk analysis and secondly that there may well be a difference of view between biomedical and clinical groups. This is an issue that would need to be overcome for such a process to be put in place and accepted.

Some months back, I was talking to my manager about risk based PM and it turned out that he had also been looking at this as well but from a somewhat different angle. Being something of a wiz at getting info out of databases he had found that out of the thousands of PM tests done on infusion pumps over the last few years only three “failures” had been found as a result of that PM testing (I will try to get the exact figures from him again and post when I have them). This means that from a patient safety point of view a huge percentage of the tests done were, in effect, a waste of time and effort. Now it could be argued that the 3 devices that were picked up did not go on to cause a patient incident but given the numbers of pumps that do fail “in-use” and the comparatively rare incidence of serious incident arising from those failures I do not think this is a particularly strong argument.

Finally (Thank God I hear you cry), does PM really reduce breakdowns? In some device types I would certainly agree that it does and in these cases I would agree with the work being done but across the board, I think not. If we take the rational approach allowed by a risk based system we can keep our safety standards a high as ever but remove or at least reduce the amount of pointless effort that we seem to spend so much time on.

Risk based PPM certainly has benefits, in the example of the Tuffsat I agree with Dave C there is no point in routine testing of this device, PPM here would not reduce breakdowns. Maybe its time to catagorise equipment based on risk and allocate resourses acordingly.

Primum non nocere!

Thanks for "publishing" (and be damned?) there, Dave. I will take a detailed look at it all later.

But immediately I should say that, noticing that you have kindly acknowledged Ottawa there ... I also notice (in the downloads) elements of both Larry Fennigkoh and Brigid Smith (F&S) and (more importantly) Mike Capuano and Steve Koritko (C&K), who expanded upon the original F&S idea. Perhaps I had better mention the later work of Binseng Wang and Alan Levenson (W&L) as well!

My point being, of course, that (as usual) we are "standing upon the shoulders of giants". Which (and on a personal note) just goes to show that some of us old timers are not actually stuck in the past, after all!

But I don't think we should worry too much about "who invented maintenance" (CM, CBM, PPM, PM, RCM ... and all the other acronyms). No single person has that claim, surely (unless it was some old dude back in the days of Noah ... a bit before my time, then). But the real point is to build upon what has gone before, in the light of experience and evolving (improving?) technologies ... and then move forward!

No ... (but) they are the top line. That is, the starting point, the bench mark, or base line.

An interesting post, Dave. And I'm sure we could all argue till the cows come home about which risk factors to consider, their relative weightings, and (importantly ... and as you point out, who gets to fill in the form) ... but it seems you have left it to me to deliver the punch line! Which is odd (or perhaps you are just being kind), as the Big Clue has already been given ...


Excellent as Leo de Kryger's .pdf document is, it doesn't appear to mention this, which I also find a bit odd (disappointing, even).

With a database system (such as, dare I say it, the TaskMaster program, these past twelve years) that include Risk-based PM with automatic interval adjustment capabilities, after running through a number of PM cycles the PM interval for each item of equipment will be automatically adjusted (extended usually, but could also be shortened) according to (yet more) rule-based criteria.* The longer the PM regime continues (that is, over the years) the system will settle down and tend towards equilibrium, happily running along with "ideal" (that is, according to all the rules pertaining) intervals for each item of equipment.

To paraphrase Goldilocks ... not too much, not too little, but just right. That is, ending up with different intervals for various equipment (and even amongst equipment of the same genre) ... thereby, of course, opening up yet another can of worms (along the lines of "do we PM all three machines today, or come back and do the third one when it falls due, the week after next"?)!

In theory (at least) towards the end of an equipment item's life, or at least when it starts to become less reliable, the system kicks in again to shorten the PM intervals (even perhaps to a point of highlighting the need for replacement).

Because of the number of tricky variables involved, it is difficult to portray the full potential of the Risk-based Model in two dimensions (without resorting to endless examples). Because it is a dynamic concept, a computer program is the best way of demonstrating what it is all about.

This level of refined efficiency is attainable. The "secret" (difficulty, wizardry ... whatever) is in thinking through and establishing the rules (criteria) and contriving the algorithms, and then setting the whole thing up! As may be obvious, I spend a fair amount of time pondering such issues myself, and (as always) invite feedback, constructive criticism, and collaboration!


Best leave that old chestnut for another thread, I think, Dave. And, as I have said a few times before (and I should imagine that most will already agree), that's not the only reason we pursue equipment PM in the "healthcare industry" anyway (in fact, come to think of it, it's a bit of a red herring, that one)!

But lastly (for the time being), here is a quote from Section 8 of DB-2006(05) (which gives official guidance for "Managing Medical Devices" in the UK):-


* See posts yet to follow about what these are likely to be ... but let's keep these posts in the realm of bite-sized chunks!

Looking again at the classic formula on page 13 of "Leo" (or, indeed, once again here), it wasn't clear to me how the Form and the Formula actually matched up. Then I realised that they don't at all. In fact the formula* is simply included (by Leo) as an example of the JCAHO model. Another red herring, then!

Meanwhile, the Form calls for simple addition of the scores.

Meanwhile, here's another resource. The same good old stuff, just (nicely) presented in a different way (Win-4 ... or Six-Sigma?).

And here's yet more bedtime reading!

* This is a variation to what I believe is known as the FSV. That is, the Fennigkoh and Smith Variations, from the classic paper published by them in 1989 (and from which most of the subsequent work on Risk-based PM is founded).

One of the really nice things about the Risk-based model is that it presents an opportunity to arrange (and conduct) PM in order of Priority. To my mind, this is a Big Plus (and is the way I would always go about things myself ... given a free hand, that is).




So it can be seen that (once the PM becomes due) the Risk figure remains the major factor, but the overall equation becomes influenced also by the passage of time beyond the date due. That is, the Priority increases each day until the PM is completed. The PM interval also has influence over Priority if the interval is altered (lengthened, shortened). The idea being that the higher the Priority figure, the more at risk or significantly overdue the PM procedure is.

Notice that at the time a PM is carried out, "the system" (program) should re-set Priority to Risk (and never allow it to fall below Risk). That is, matters are arranged so that Priority is always equal to, or greater than, Risk. The Priority figure only starts to become greater than Risk once the PM interval has been reached (and passed).

One of the arguments sometimes brought out against this approach is that, by concentrating on each successive High Priority PM (and, don't forget, we're talking about a dynamic system here, that changes with the passage of time) that low Risk items may never get seen. The answer to this is that, given enough (passage of) time, even those items that started off at a low Risk level will slowly climb up the list. Just check out the formula!

Here is a list of Six Sigma Corporations - some familiar names on that list....

Indeed! But I don't see the NHS mentioned ...

"Real" industries are full of this stuff. For example (and there are many others), how about ... The Unipart Way?*

* Yet another system aimed at reducing waste and eliminating activities which do not add value.

Paul, (or anyone else for that matter), with regards to the Estates Journal article, would you have contact details for anyone @ Papworth who was/is connected with this work? I would like to contact them and explore this further.

Any forum folk working there?

Ta,

Yes, Paul himself, for starters!

Thanks Geoff, straight to the source !

Afwan. All part of the service!

And looking forward to some more posts on this interesting topic!

I'm preparing to present to the Environment of Care committee at WRMC, my suggestions of implementing a reliabiltiy-centered-maintenance strategy focused on select type of devices. We currently rely on a risk-based program derived from the original F&S model. Approval to conduct RCM and FMECA analysis will have to get by my VP, Risk Managment, and other non-technical upper management. Not having any luck finding other local institutions that have tried the RCM approach. There are several organizations here in the US that are actively recommending the clinical engineering community to engage the RCM in healthcare topic. Of course there are other types of tactics being discussed, evidence-based-maitnenance, gradient risk sampling. Its been easy to find articles and suggestions, not so easy to find any CE depts that have implemented. My instinct is that RCM would best be applied to high-volume, mobile assets e.g. IV pumps, vital-signs monitors, electric beds, stretchers, wheelchairs.

Hi Rick,

earlier thread I was searching a cheap/fee Risk Based PM.

http://www.ebme.co.uk/forums/ubbthreads.php/topics/41835/1

Lots of acronyms and abbreviations, there, Rick!

Here's another one:- HPM!*

What's that? Holistic PM. Isn't that what Risk-based PM really is (or perhaps that should be, er ... should be)? That is, a consolidation of all the earlier "PM's", taking the best (and most appropriate) aspects of each? Including (and again I stress the point) the ability to adjust PM intervals according to sensible and appropriate criteria.

I don't think that the "massive upheaval" model is the way to do the thing, especially (as you have indicated) that most likely means having to convince the dull and the ignorant before you can even take the first (hesitant?) steps. When you think about it, you can implement the tenets of the Risk-Based Model quietly, and in a time frame of your own choosing (or even, not at all). Simply overlay it on whichever system you are currently using.

I would suggest this approach. Implement it on an "as and when" basis. At first (at least) no special software is required. Just start off by thinking deeply about Risk Criteria, then apply some to a few types of equipment. Document what you are doing as you progress, note any changes you decide to make, and ... just take things from there. That is, add, build, develop, improve ... step by step, recognising from the onset that benefits will only accrue (if at all) over a number of PM cycles (meaning, of course, over a number of years). This is no "quick fix" ... and that's why it is unlikely to appeal overly much to the suits and bean-counters.

Lastly, by all means "stand on the shoulders of giants" (F&S, and all the others), but I would urge you also to sit down and objectively appraise the situation where you are. And then come up with your own Risk Factors (and Risk Scores). In my experience, your guess (and mine) is just as likely to as valid as anyone else's. You can always make adjustments later on, in light of continued experience. The criteria need not (should not) be set in stone! As long as you ground the thing in sound engineering, and common sense ... whilst disregarding any pressure to "save money" (because that's not what it's all about), you will find it to be a most worthwhile (dare I suggest enjoyable) exercise, no doubt.

* HPM (c)2009 me!

Appreciate the responses to my ?? regarding RCM strategy related to medical equipment. Judging by responses from the US based BMETS-ONLINE listerve it does seem to me that there is not a widely accepted alternative to numeric risk calculations and interval based tactics that I could propose to my EOC committee at this time. Due to citation from our accrediting authority
last October, Clin. Eng dept has been under the microscope so to speak and we can't implement any changes to risk classification or PM interval without the express approval of EOC, Risk Management, legal and compliance officers. Since Novermber 2008, we have been able to adequately demonstrate our ability to maintain a 100% completion rate on "life-support" and 90%(barely) on "non-life support" devices, but I'm not sure when dealing with shrinking resources this can be maintained indefinitely. I shall continue to monitor biomed listerve sites along with the ASHE maintenance practices task force web-site (http://www.ashe-mptf.org)and see if the "best practices" maintenance recommendations idea sharing proceeds.
Geoff, I think we shall go ahead as you suggest, do our internal data failure analysis, share with other service groups, and hold off the presentation to our Environment of Care (Safety)committee until a more receptive atmosphere exists.

Yeah, (to coin a phrase) "just do it"! You are the local expert, not "them". And by the time you are able to demonstrate results, "they" will have long gone*, no doubt about it!

Just select a few types of equipment for a pilot scheme, and take it from there. Infusion pumps might be a good place to start, I would have thought.

Thanks for that link. It's an interesting resource.

* Only to be replaced with more of the same, unfortunately.

I came across this resource (by accident, as usual)! It looks like there's a wealth of good stuff there.

Earlier I had been listening to an interview on the radio about "Predictive Policing", and that set me thinking about predictive this, and predictive that (medicine, maintenance etc.).

Proactive? Yes, that's how it has to be. I'm not yet sure about Predictive Maintenance (in our context, that is), but believe I could be a champion for Predictive Service per se.

By that I mean my usual mantra of "getting out of the workshop* and onto the wards" with the aim of nipping problems in the bud, anticipating problems down the line, spreading the gospel of good equipment husbandry, listening to users, and other good stuff like that! This is nothing new, of course, but something that many of us have been doing for years.

I seem to recall hearing about a strategy once called "Management by Walking About"!

* Despite the view that Dave in Oz seems to taken of yours truly!

Useful Site Geoff loads of stuff there...nice discovery

As mentioned earlier one of the key elements of the Risk-Based PM scheme is an ability (an option) to automatically increase or decrease PM intervals according to the condition of equipment as encountered at PM visits. To my mind it is always the actual condition of equipment that really matters (that may sound obvious, trite even, but I believe it is sometimes lost sight of). So the ability to adjust intervals based upon condition makes sense to me!

Don't forget that we have already established our initial intervals and priorities for PM based upon risk levels.

With automatic interval adjustment, as the PM scheme continues to take effect (that is, as time marches on), PM intervals will eventually break away from those that were initially set by the risk level.

Here is an example (using typical criteria). PM intervals may be shortened or lengthened based on two basic conditions:-

Firstly the condition must be met that the three previous PM intervals must be approximately equal (that is, for any further question to be based on a "fair" sampling).

Secondly, if a repair was needed at all of the previous PM's then an interval reduction is triggered. In an effort to prevent potential failures, it looks like we need to carry out PM more often. So let's reduce the interval by 50% and see how we get on with the next three visits.

However, if no repair was needed at all of the previous PM's then an interval extension is triggered. OK, let's increase the interval by 50%.

If one or two repairs were carried out, we leave the interval as it is. It has to be a "straight flush", as it were, before any change is triggered.

So it can be seen that we need to be careful to record whether a repair was needed at each PM we carry out. This is a crucial point. Naturally, we may also need to be clear in our minds what we actually mean by "repair" in this context.

Now we need to look a bit more closely at the criteria involved.

In the example above we used:-

1) An interrogation of the previous three PM's. So there's our first variable. How many PM's to look back through (to see if repairs were carried out). We could call this (key) variable the "Recent PM's repair check".

2) Three PM intervals of "equal" length were required. We need to allow a bit of slack here as to what we mean by "equal". Plus or minus ten per cent sounds reasonable (eg, for a nominal 180 period, we could allow between 162 and 198 days). Anyway, let's call this variable the "Equal interval bracketing" (see how easily these trip off the tongue)!

3) We used an interval adjustment of 50%. So, for an interval starting off at 180 days (for example) we would increase to 270. Or decrease to 90 days. If the pattern of repairs (or none) was repeated following the next three PM cycle, these would become 405 and 45 days respectively. Obviously if we had actually encountered a run of six repairs needed at PM in a row we would (hopefully) have done something else rather than simply continue to attempt PM! This one can be known as the "Interval adjustment" (fair enough).

Here are some suggested figures to play around with:-

1) Recent PM's repair check:- min 1, max 9, default 3
2) Equal interval bracketing:- 5 to 50%, default 10%
3) Interval adjustment:- 10 to 90%, default 50%

... all arguable, of course (just like the risk levels)!

But (as I say) I would regard the "Recent PM's repair check" as the key setting. If you wanted to see quick results, this would need to be set low. With it set at 1, for example, the system would very quickly break away from the initial intervals, as it would look back at only the last PM to see whether a repair was needed. It is debatable whether a single interrogation would give sufficient justification to trigger an interval change ... but I'll leave that for you all to ponder.

Addendum to the two posts above ... I have been having problems editing these this morning (with the wierdness of an earlier revision finally lodging itself in place) ... but never mind.

But (just to be clear) when I say all of the previous PM's in the first post, I really mean "all of the previous three PM's" (as we had chosen three as our "Recent PM's repair check" sample).

And, at the post above "... as it would look back at only the last PM to see whether a repair was needed" ... would have better phrased as:-

"... as it would look back at only the last PM to see whether a repair had been needed"!

Semantics? Not really. Just clarity, I hope.

With the Risk-Based PM model, once we have established Risk level figures for each equipment type, we can begin to assign PM intervals accordingly.

Remember that our equipment Risk level figures are simply a totaled score (plus and minus) of a list of weighted numbers that we have established to indicate the perceived risk of failure (primarily, risk to the patient, that is). The greater the risk (the higher the Risk figure), the more often PM is needed (as those who believe in PM would expect ... and you have to believe)!

In turn the Risk governs the frequency of PM (that is, how often it needs to be carried out). Risk and frequency are directly related. As, in turn, are the intervals between PM's in days. So let's begin by assigning 365/Risk as the PM interval.

But having done this, we will most likely be faced with a list of PM intervals that bear no resemblance to those we are traditionally used to. They will probably be much shorter. So to get things back into the realms of reality, we need to apply a common factor (also known in the trade as a "fiddle factor") to all our Risk levels in order to stretch out PM intervals to within the bounds of accepted norms.

A method I have found useful is to establish the average Risk for all equipment under the scheme and work on that figure (that is, the sum of all equipment Risks divided by the total number of equipment items), then decide what is the typical interval you are (or your organisation is) comfortable with (180 days, for example ... let's call this interval the "Initial Set-point") and apply the formula below to arrive at your Factor:-


Once we know our Factor, we can then plug it into the following formula in each case:-


When you sit down and think about it, and play about with a few figures, it all becomes obvious enough!

Combined into a single formula, for each equipment type (that is, each Risk):-


Don't forget that (as mentioned in earlier posts) if you adopt an automatic interval adjustment protocol on top of your Risk-Based scheme (and, why not?) then the PM intervals will tend to step away from those calibrated by the Initial Set-point once the auto adjustment criteria begin to take effect (that is, as time marches on).

Remember also that, in each case, PM Priority is set initially to Risk. Priority should never be less than Risk. Once the Priority figure increases beyond the Risk figure, the more overdue the PM.

The biggest obstacle that I can see is that the equipment with the highest risk factor is usually connected directly to the patient and therefore the availability for PM is very difficult to schedule, we asked the ICU's to inform us as to when a room, patient bed becomes available and we will PM all the equipment within the vicinity, seems to work even if we PM more than scheduled for each area, better safe than sorry.
PS Happy New Year.

That is a practical "real world" failure, rather than a failure of the logical system! Regardless of difficulties in accessing equipment, and all the rest, the Risk-Based system will continue to generate those high (ever increasing, once PM is due) Priority numbers, just as it's designed to do!

Conversely, any PM completed early won't upset the balance of things too much (in fact, not at all). As far as "the system" is concerned, it would simply be so much wasted effort. It will just reset the interval clock in each particular case, and start its happy task of counting up to the next due PM date all over again!

Out of kilter PM will affect the smooth running of the auto interval increase option, of course. It will effectively nullify it!

Here we are, two years later, and nothing more has been added to this thread.

So here I am, two years later, dragging it back into play.

I remain convinced that Risk-Based PM is the answer. So, as we haven't heard anything to the contrary, I'm hoping that everyone is following this PM model now.

I get quite a few complaints that we should stop old threads being regenerated.





Please start a new thread, if one is necessary.
Topic locked.