John Senders
Professor Emeritus of Industrial Engineering at the University of Toronto; Adjunct Professor of Law at York University (Toronto); James Marsh Professor-at-Large, University of Vermont (Burlington)
“We have the general human tendency to make mistakes.” (1:09)
Human factors, broadly, incorporates two parts of any tool. A tool can be a hospital, or it can be a scalpel, or it can be a pencil. And the two parts are the capabilities, limitations, and capacities of the user, which provide the freedom for the engineer to design, but the engineer, or designer, must operate so that nothing is called for that is not within the capability of the user at its best. In other words, it should be organized in the design to be optimally matched to the capacities of the user. That is human factors.
Coincident with this, we have the general human tendency to make mistakes. One of the major problems of modern medicine is that a significantly large number of people are injured or killed every year in our hospitals as a consequence of human error.
“It’s the noise, which really is human error.” (1:23)
I became interested in human error, per se, in I think it was 1977 or thereabouts, as a quite accidental event. I was at an Air Force Office of Scientific Research meeting, and had the task of listening to everybody else and then commenting on it. And I listened to what they said — and these are all old friends and colleagues of mine ― and I was quite familiar with what they did. And then I listened to what I said, because usually what comes out of one’s mouth is not necessarily deliberately formulated, but it’s the brain working, and I learn a great deal by listening to myself. So I heard myself saying that “Your study has been devoted to what people do correctly and characterizing everything that was incorrect as ‘noise’ that we will try to get rid of; we’ll design out the noise in the mathematics.” And I said, “You’re all wrong. It’s the noise, which really is human error, that kills us, destroys cities, breaks thinks apart, wastes money, and loses wars. And you ought to go home, all of you, and work on the errors, look at them — What were they? What did people do wrong? Why did they do it wrong? ― rather than adding them up and saying, ‘Only two percent error.’ Two percent error will waste at least two percent of your budget.”
“One has to back off from looking at the specifics and ask what the generalities are.” (1:45)
Each new device presents new opportunities for error. So one has to back off from looking at the specifics and ask what the generalities are. And these generalities actually were marvelously expressed by a very early writer on human error: Jeno Kollarits, who was a Hungarian neurologist/psychiatrist who, fortunately for me, published in German not in Hungarian, a particular paper on observations of “action errors” [titled, Observations on Dyspraxias (Errors of Action)] ― picking up this drug instead of that drug. He published it in 1937.
He did a “Linnaean” approach; he collected errors, classified them, constructed taxonomies, and erected the simplest of possible analytic causal mechanisms for that. And these are really very sophisticated.
In the first place, the phenomenological approach to error says that “If I fail to do this, I forget to do it, I overlook it, and I omit it, that’s an error of omission.” And I can have an error of substitution, or I can have an error of doing it and doing it again ― repetition. And so on; in fact, there are four: I can do it when it is not called for at all, which is an error of insertion. The thing about that taxonomy, the phenomenological taxonomy, is that it’s extremely useful. It tells you what you have to do in the outside world to prevent the error from reaching the patient.
“A general principle, which applies throughout medicine: We make it difficult to do it wrong.” (1:57)
So Kollarits’s taxonomy is: omission, repetition, insertion, and substitution. It turns out that, of his errors, 70 percent, approximately, are [errors of] substitution, and his corpus was more than 1,100 errors, which means that it’s bigger than any diary study ever done. And that suggests that the first thing that should be done in medicine is to make sure that something which is not needed at a particular stage in a procedure is not there to be substituted for what should be done. That’s a principal rule. If a surgeon has a favorite array of anesthetics or injectibles set up next to the operating table, and if some of these would be lethal or injurious if taken out of order, then even though that surgeon wishes to do it, she should not be permitted.
The other thing that Kollarits did, he evoked the principle of least effort; he called it the Hamiltonian Principle of Least Effort: Everyone does as little work as one can get away with. Kollarits’s principle translates into this dictum: “If it is easier to do it wrong than rightly, the error is very likely. And the easier it is, the more likely.” So it should be difficult to do something wrong. If I must choose between these two, and I want to make sure that when I choose I choose this one, then “this one” can be put further away. So that’s a general principle, which applies throughout medicine: We make it difficult to do it wrong.
“The communication of error is mandatory… We have to get rid of secrecy.” (1:54)
At one point I investigated a death in a hospital; it was due to improper blood type. And it was a very complex sequence of events, but it turned out that it wasn’t really improper blood — it was that the patient was the wrong patient. And this, by the way, also turned up in an examination of reports in Florida, and the two errors were both classified as blood type errors. That was the causal factor of death, but that wasn’t really what was at issue. What was at issue was that, in both cases, the wrong patient was in the room and received blood that had been deposited, as it were, or the correct type, for the other patient. So if you treat it as a blood error, you start cleaning up the blood system, but you don’t clean up the patient identification system.
So I found this in the hospital I investigated, and then a year later I found myself in the other hospital of this network, a major hospital, having a quadruple bypass, and when I was ambulatory, I walked around looking for trouble, as I usually do, and I found that they used exactly the same separate, antiquated, and incorrectly designed blood typing record system. Everything else was mechanized but this one. In other words, the first hospital had never told the second hospital about how to prevent future error. So the communication of error is mandatory. That means, if I make an error, I must shout it aloud so that everybody knows what happened to me, and then they can make sure, if they can, that it won’t happen to them. We have to get rid of secrecy.
“It’s clear that in the conceptual construct of error, it is not an intentional act.” (2:04)
An error is by definition unintentional; if you intended to do this thing, you’re guilty of malfeasance ― guilty of deliberate negligence. It’s clear that in the conceptual construct of error, it is not an intentional act. So if you have something which cannot be predicted, cannot be controlled, because you don’t know that you’re going to do it, and has adverse consequences . . . In law, if a meteorite falls through the ceiling of your house and injures a guest, you’re not responsible because that’s called an Act of God; you couldn’t know that, you couldn’t predict it, you couldn’t stop it from going through the roof because you couldn’t build a strong enough roof! But you’re not responsible; it’s an Act of God, an A-O-G. An error meets those criteria, and it should be characterized as a Mental Act of God, an M-A-O-G.
You must believe that, in which case there has to be . . . and here I will read to make sure I do not err of omission:
- Prompt admission of error;
- Full description;
- Assertion that learning to prevent will take place; and
- Offer of rational compensation.
Wherever that has been tried, it has resulted in a reduction of litigation. And it also results in a reduction of distress on the part of the surviving family. Because they’re willing to recognize error, but they will not tolerate lies. And most of these things, these lawsuits, stem from the fact that there’s been denial, non-admission of responsibility, evasion, and attempts to attribute the death to the patient: “He did it to himself.” We have to behave rationally, and these would be the rational steps to take.
02/04/2009
