CHI+MED’s error expert Dom Furniss has written a couple of short articles for the cs4fn website about unavoidable piddling – when you just can’t hold it in any longer. From the examples of two people who were desperate for a wee – one showing remarkable presence of mind under the circumstances – we learn about knowledge gaps and slip errors. Examples of how people make every day errors helps researchers (and students) understand and categorise the types of errors that can be made in a medical setting, for example where medical devices are used (and this is what the CHI+MED project is researching).
In the first story a man, being given a lift home, hopes that the discomfort of urgently needing to go to the bathroom might be relieved if he ‘lets a little bit out’, just to take the pressure off. Unfortunately it does no such thing and he’s suddenly faced with increasingly visible evidence of this. Although, surprisingly, he manages to cover things (not literally) rather successfully, his lack of knowledge that once you start peeing it’s quite difficult to stop completely is what let him down here. Had he not attempted to let a little out he might have avoided the problem.An example of a knowledge-based error that had a tragic ending was that of someone who’d been prescribed skin patches containing pain-relieving fentanyl – the patch delivered a steady dose of the medication unobtrusively. Unfortunately the person didn’t know that a hot bath would increase the rate at which the drug was delivered and sadly the patient died of an overdose shortly after putting on a new patch (without removing the old one) and getting into their bath. In the second story a woman makes it to the loo cubicle just in time to prevent an accident… unfortunately she makes a critical ‘slip-based error’ and ends up having the accident she was hoping to avoid. These errors are ones where you know what you should do (you have the right knowlege) but you still do the wrong thing, albeit unintentionally. Usually a lapse in memory or attention is to blame and while wetting yourself is embarrassing (particularly when you’re actually in a loo cubicle at the time) they can have far more serious consequences in medicine. If someone is having chemotherapy and the infusion pump that delivers the medication needs to be changed then, if the nurse forgets to close the clamp to stop the flow, there’s a danger that the drug will flow freely into the patient rather than at the controlled rate delivered by the pump. This can cause an overdose but most modern infusion pumps now protect against this – if free flow occurs the pump will automatically cut the flow. As Dom says “Good design can guard against these kinds of slips everyone makes occasionally.”