Event Investigation and Analysis Guide: Appendix A
Five Whys
In this example, there is only one path shown, but answers can create multiple paths and more questions.
Event Summary: The wrong concentration of potassium (K+) was used in the compounding of TPN. This was discovered almost 2 months later.
1st Why: Why was this concentration of K+ used in the compounding process of TPN?
When the drug was brought into the facility, it was a different concentration from what had been used in the past, but was entered into the database by the pharmacy technician under the same barcode as the previous concentration.
2nd Why: Why was the concentration different?
There has been a drug shortage of the concentration that we typically use, and we had no choice but to order a different concentration.
3rd Why: Why did the pharmacy technician enter the drug as the previous concentration?
There was a breakdown in communication, and she wasn't told when a different concentration had been ordered or that a different concentration had been received. We've always used the same concentration. Also, the labels are very similar and the print is very small. She didn't realize it was a different label when she manually entered it into our database.
4th Why: Why was the drug information being entered manually?
Our computer system is not connected to the National Drug Database, so we can’t simply scan the bottle and have the information entered automatically. We have to enter every drug into our database manually. If someone misreads a label or makes a typing error, we do not have accurate information in our database. Our database only knows what we tell it. In this case, the drug was entered as the wrong concentration. So, we had a case of "garbage in, garbage out."
5th Why: Why do you think the pharmacists or technicians who put the drugs on the compounder did not notice that the concentration was different?
If we do not have accurate information in our database, our redundant safety measure of scanning the bottles to make sure we have the right medication doesn't work. In this case, the database was confirming incorrect information. Also, when the bottles are on the compounder they are upside down, so that makes them even more difficult to read. Some manufacturers put the concentration information on the bottle upside down, but this manufacturer doesn't.
If the interviewer stopped after getting the answer to the first why, one might conclude that the root cause is that the person entering the data into the system was not vigilant. If the person stopped after the 3rd why, one might conclude that the root cause was a breakdown in communication. However, if one continues asking why, it becomes apparent that there were several root causes that included poor technology for supporting the tasks, poor medication labeling processes that are not optimal for the medication shortages, and a reliance on using people to double-check that technology is working properly.
