Thursday, November 19, 2009

The KK Chemo Misdosage Incident

I must confess: I had just about zero interest in the story of the chemo overdose.

Then Khaw Boon Wan made the comment on the similarity of the pumps, and someone ranted about it in their blog, specifically citing human factors.

I happen to work in a human factors laboratory. No, I don't design medical devices (despite having originally trained as a biomedical engineer).

Labelling the pump that dispenses in ml/hr in a different color from the pump that dispenses in ml/day would be an obvious remedy that would have addressed the KK incident. It's the common-sensical solution that anyone can think of.

Ah, but if you were an actual human factors professional, I can assure you that things would not be as simple as that.

Sometimes, design flaws like that really do occur because engineers can't see the wood for the trees. It never occurs to them that someone handling the pumps might actually make a mistake that could result in fatal consequences. That's when having a human factors professional as a member of the design team helps: by explicitly designating a person to consider human-centric issues.

But sometimes the team is aware of these issues and highlights them to management, but the manufacturer still proceeds as before. Why is that? Because in addition to design principles, one must be mindful that there are always business considerations at play as well. Manufacturing two (or more) separate designs for pumps incurs greater costs, eliminates the ability to standardize across pumps, increases holding inventory, and overall increases complexity of business and manufacturing processes, and decreases economies of scale. All this naturally reduces profitability.

It's not just pumps. Even medicines are typically sold in identical-looking vials with identically colored vial caps, with only the text on the vial labels differentiating them in both drug type and concentration. You can imagine what kinds of accidents can potentially happen there.

The point is, in both these cases, business considerations override human factors. Legally, the manufacturer has clearly labelled on the pump (in text) the appropriate dosing regime, or for a medicine vial, the type of drug and concentration. The manufacturer has hence fulfilled its duty. Therefore, if there are any mistakes in dosing, the liability for the error lies with the hospital and not the manufacturer of the product. The victim of such a dosing error can be said to be an "externalized cost"; the beneficiaries of the victim's suffering are the manufacturer, who enjoys greater profitability, the hospital, which enjoys greater cost-savings, and the public, who save on healthcare. 

Is it ethical of the manufacturer, to "pass on" liability to the hospital? To make it difficult (or at least not easy) for the hospital to administer the right dosage? Maybe the manufacturer is at fault, but IMHO, it's very hard to say. The reason why I am so ambivalent is because I am able to see the big picture. 

If you were the administrator of a public hospital, charged with keeping healthcare costs low, and you had a choice between more expensive but better designed equipment, and less expensive but poorly designed equipment which nonetheless gets the job done, which would you choose to purchase?

The pressure to keep costs low is immediate and apparent, but the fallout from a medical error only comes when an error does happen. Not to mention errors by nature rarely occur, and it's not like well-designed equipment eliminates errors; they only reduce the probability of occurrence.

Given this reasoning, a typical hospital administrator would probably (and not unthinkingly) choose the most cost-effective product that gets the job done. Repeat this scenario across the whole hospital sector and manufacturers that produce the better designed product simply cannot compete. So all manufacturers end up making the generic, not very well-designed product, and of course, it makes perfect business sense to do so, seeing as how manufacturers can reap the economies of scale.

And that's how we end up in the current situation.

When a chemo incident like the one that happened in KK occurs, there are cries of public remonstration, and the pendulum may swing the other way. Hospitals might make the decision to purchase more expensive and better designed pumps (that is, if they are available). Then years down the road, when a bureaucrat (or a management consultant) with an eye to trim costs looks through the hospital purchasing orders, they may make the suggestion that $XXX could be saved by buying the generic version of such-and-such a product, instead of the more expensive version. And they would not be wrong, just...myopic.

Then the cycle starts again.

Sometimes it's not only about human factors. It could be about policy, or human nature, or business fundamentals, or just the plain old, dysfunctional way the world works.


conscience said...

Would different coloured labels pasted on the pumps be a simple solution to distinguish the two types of pumps?

mjuse said...

That sounds simple and reasonable. However, it is still possible for the staff charged with labelling the pumps to mislabel them with the wrong colors. If you had to label a hundred pumps in one sitting, could there be a chance that you would mislabel a few?

Also, labels do peel off over time and need to be replaced.

i'm not saying that color labels are a bad solution, but the person looking for a solution may want to consider also how the problem came about. sometimes, the problems may be solved by changes in procedure rather than objects.

if i were part of the investigating team for instance, i might for example look into where the pumps were stored in the hospital. it might be logical to place the ml/min pumps next to the ml/hr pumps, but that kind of convenience could be an invitation to mishaps.

maybe errors arose because there was just really bad lighting in the storeroom and it was easy to mistake taking the wrong pump. color labels may not be too helpful in this case (although it should be apparent once the nurse steps out of the storeroom with the wrong pump).

i might look into how the pump is chosen, handled and hooked up to the patient. errors may arise because multiple patients with different dosing regimes need to be outfitted with pumps by the same nurse at the same time. even with labels, the nurse might be swamped with work and get a little frazzled. There might be an opportunity to introduce checks during this process, perhaps by a second person. or only one person should handle ml/min, and another ml/hr.

bottomline is, it's usually a good idea to identify and understand the antecedents of the problem before applying ideas for solutions. still, simple color labels are a good workable solution that should be considered.

conscience said...

My earlier post intended that the whole unfortunate incident could have been avoided if any of the medical personnel who uses the pumps had raised concern about the design of the pump (if it were indeed an issue as stated by Khaw Boon Wan). Perhaps a simple solution of using coloured labels to differntiate the pumps could have prevented the mix-up. Question is why no one cared/dared to do so.

mjuse said...

why didn't anyone suggest using colored labels before this incident had occurred?

who knows? it could be for any one of a hundred reasons. it's a lot easier to speculate why something occurred than why something didn't occur.

the simplest reason i can think of is: mixing up the pumps had never been a problem before. so there had been no need to use labels.

you know how the old saying goes: hindsight is 20/20.

using the example of the lack of colored labels to insinuate that there is a unhealthy top-down culture in the hospital, or a lack of initiative on the part of ground level staff is a bit of a stretch though, IMHO.

conscience said...

Perhaps no one bothered because IYHO, no point labelling the pumps as there is always the possiblility of mislabelling them with the wrong colours. "If you had to label a hundred pumps in one sitting, could there be a chance that you would mislabel a few?" Perhaps, if the quality control and checks are not effective. Better than having to tediously checked EVERYTIME that you have to use them right? Possibilty of human error would have been even higher right? No where in my posts did I insinuate that there is a unhealthy top-down culture in the hospital. So why put word in my mouth? Why would questioning be unhealthy and keeping silent as there "never been a problem before" is ok? Perhaps its only ok for some experts to "identify and understand the antecedents of the problem" while everyone are to keep silent and leave it to the experts. We'll leave the expert alone.

mjuse said...

my, you're the combative sort aren't you?

my intention was not to state that using simple colored labels was an inadequate solution. it could be an excellent simple solution. i was highlighting other ideas that could be looked into along the way in the comments section.

as for my contention that you were insinuating that hospitals had a top-down or apathetic culture, if that was in error, then i apologize. i may have misinterpreted when you wrote "Question is why no one cared/dared to do so."

finally, with regard to your snippy little comment "We'll leave the expert alone", i may work in the field, but i never claimed to be an "expert", nor to have all the answers.

my original intention in writing this post was to paint the picture of potential conflicting interests (eg. the hospital, the manufacturer, taxpayers etc.), and not to dissect ways in which such an unfortunate incident in KK could be prevented. so this line of discusson is digressing away from the original intention of the post.

you may reply to this comment in the same vein if you wish, but i have nothing more to say on this issue.

Gerald Tan said...
This comment has been removed by the author.
Gerald Tan said...

Mr Khaw was wrong - The incident did NOT arise because two different pumps that looked alike were used.

The incident arose because a SINGLE pump which could be programmed for BOTH ml/min and ml/hour was used. If you ask me, that's a design feature, not a flaw. The error arose because the pharmacist mis-programmed the machine into ml/min instead of ml/hour. (Telling me you want a pump that only goes ml/min is like saying I want a watch that only tells me the time in minutes. If you want to know the hour, you need another watch).

Only AFTER the incident, did KK change to TWO different types of pumps. (In fact, if you asked me, they probably still used the same pump, and just smashed the button that allowed you to toggle between ml/hr and ml/min).

Minister Khaw, in all his esteemed wisdom, thought that this was the original design and proceeded to critise it. So in fact he (and the rest of us) are criticising the solution.

mjuse said...

Thank you for your comment Gerald. I guess this makes much of my post moot. Perhaps this teaches me the lesson that I should refrain from commenting on something I haven't seen or touched myself.

It does make sense however, for a pump to have multiprogrammable functions.

I wonder if twice repeated confirmation entries are required for the pump, similar to the iSTAT?