Patient Safety Tip of the Week

September 11, 2007    

Root Cause Analysis of Chemotherapy Overdose


root cause analysis has been published on an unintentional chemotherapy overdose that gained the attention of the Canadian media a year ago. This is an extremely well done RCA that has numerous lessons learned and should be read by anyone involved in patient safety, whether your facility is involved in cancer chemotherapy or not.



The RCA was coordinated by the Institute for Safe Medication Practices Canada and utilized the Canadian Root Cause Analysis Framework developed by the Canadian Patient Safety Institute, ISMP Canada, and Saskatchewan Health. For those unfamiliar with that RCA framework, it is an excellent comprehensive overview of the elements of a thorough RCA. It incorporates most of the important elements of the more widely known Veteran’s Administration root cause analysis tools and adds elements from a variety of other resources.



The case involved a 43 year old woman who was being treated for an advanced nasopharyngeal carcinoma with a chemotherapy protocol of high-dose fluorouracil and cisplatinum. The chemotherapy was to be given intravenously by an infusion pump over a 4-day period. However, the pump was inadvertently programmed to infuse the entire contents over a 4-hour period instead. The patient died as a result of the mishap.



The RCA clearly developed a timeline and an understanding of what happened, then did a cause-and-effect analysis, resulting in three causal chains and multiple associated findings or incidental findings that are equally important in identifying opportunities to improve patient safety.



The discussion on the causal chains leading to incorrect programming of the infusion rate is excellent and focuses on many of the individual issues we have mentioned in previous Tips of the Week. The formula the bedside nurses had to use was incredibly complex and they did not have at hand all the information needed to make the calculation. The medication label not only had several features not in keeping with good human factors design principles but also included unnecessary information that may have increased the opportunity for false confirmation of the infusion rate. The double check process did not catch the programming error and there was a lack of feedback from the pump that further reduced the opportunity to notice the incorrect infusion rate. The description about how several advanced technologies were poorly integrated and actually led to increased cognitive workload is particularly informative.



All the above occurred against a background where the potential toxicity of the regimen and the lack of an effective treatment for overdose did not appear to be fully appreciated by numerous members of the healthcare team. Much had to do with the dearth of published literature on fluorouracil overdosage.



Many of the most useful comments pertain to the response to the incident. The recommendations expand upon some of the important points we included in our July 24, 2007 Tip of the Week on an incident response checklist. They also showed how multiple other individuals would have had similar difficulties programming the pump and nicely illustrated how a facility needs to assemble a representative group of end-users during the pre-purchase phase of any investment in new technology in order to identify potential usability and safety issues.



The recommendations made in the RCA are well thought out and do take into consideration possible unintended consequences. The recommendations extend well beyond the facility and include recommendations for manufacturers, regulators, safety organizations, etc. A followup to that RCA was also published in the August 20, 2007 ISMP Canada Safety Bulletin .



This is an excellent RCA and a model for doing a good RCA. In fact, our sole criticism has to do with their prioritization of causal statements. The treatment protocol design was ranked #15 on their list. We would have ranked it at or near the top of the list. A high-reliability organization would assume that something could go wrong with the infusion process and ensure that, if it did go wrong, irreparable harm would not take place. We see this as akin to the concentrated potassium chloride issue. We understand that convenience of the patient must have been important in development of the chemotherapy protocol but inclusion of 4 days worth of fluorouracil (plus a single high dose of cisplatinum) in a single IV bag enabled the fatal outcome when subsequent errors occurred. A “safety culture” would likely have said “what is the highest dose that a patient could tolerate in one day (or less) if there was inadvertent administration of the infusion?”. A safety culture would have designed the protocol with sublethal dosages that would have protected the patient in the event of “what can go wrong will go wrong”. It also would not have put the healthcare workers at the “sharp end” in a situation none of us would want to be in.



All the people who contributed to this excellent RCA are to be congratulated. This is clearly the type of incident that could occur today at multiple healthcare facilities and provides numerous useful lessons you all can use. You need to read it because many of the same issues occur in processes your facility uses today. It’s also a great teaching tool to use with your RCA Team or any multidisciplinary team involved in patient safety.


Addendum: The September 20, 2007 Medication Safety Alert from ISMP also includes a summary of this case. 








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