How to Achieve Zero Retained Foreign Objects with DMAIC Part II

In my last column, I discussed the Define phase of the retained foreign objects project. In this entry I will discuss the Measure phase of the project.

Defining the Measure Phase of the Six Sigma DMAIC Model

Some of the activities undertaken in the Measure phase of the Six Sigma DMAIC model include collection of baseline information on the process and/or defects, cause and effect diagrams, failure mode effects analysis, measurement system analysis, key process inputs and outputs, among other tools. It is important to realize that the Measure phase of the Six Sigma DMAIC model goes above and beyond just measuring defects. It encompasses developing a deeper understanding of the process using the indepth process mapping, identifying the key process variables and, more importantly, measuring what is important for the project. I believe that using existing measures makes sense from the cost and/or time constraints, but the Six Sigma team could overlook the "hidden opportunities" for process improvement. Therefore, Six Sigma teams should look for additional and/or novel ways to measure process improvements for the Six Sigma project.

Using the Six Sigma DMAIC Approach: The Measure Phase of the Retained Foreign Objects Project

For the retained foreign objects mitigation Six Sigma project a thorough investigation into all surgical retained foreign objects and near misses were undertaken. (Note: near miss events are those that had a discrepancy in the counts and a thorough investigation, usually using high resolution X-rays that do not reveal any retained foreign objects). Some interesting facts emerged during the analysis of the 34 actual retained foreign objects events out of about 200,000 surgeries over a four year period. In 62 percent of the cases, the counts were actually reconciled prior to end of surgery. If the counts were correct, how did the retained foreign objects get caught? At the Mayo Clinic, Rochester, patients meeting certain criteria (for example, when the body cavity is operated upon), routinely get X-rays done prior to going to post operative care unit, irrespective of the counts reconciliation.

For an outsider without healthcare experience, it does not make sense that the operating room staff is not able to keep track of items used in surgery. In human factors this is referred to as inattention blindness due to conspicuity (sensual or cognitive), mental workload, task interference, confirmation bias, capacity, among other factors. One must realize that the operating room environment is very complex and a manual counting process is error prone. I am by no means an expert in surgical process improvement, but in the scores of surgeries I have observed, it is not uncommon to have 200 plus items used in surgery (sponges, instrument, sharps, etc.).

The Six Sigma team conducted an extensive literature review, and they realized that the common causes cited for retained foreign objects such as emergency cases, unplanned changes in procedure, etc., did not contribute to retained foreign objects. The only common theme found was that of the "communication lapse." The Six Sigma team also realized that the policies and procedures were amended several times in response to specific events (band aids), adding to the confusion of counting. The Six Sigma team revised the policies and procedures, to align with external requirements and internal best standards. The key to developing the policy was using the multi-disciplinary team to get the buy-in from the various departments supporting surgery (surgery, nursing, radiology, etc.).

The Six Sigma team also collected benchmark data for retained foreign objects and realized Mayo was in the top tier (one of the lowest retained foreign objects per 1,000 surgeries). (The project champion’s response: We must be the best; being good is not good enough.) Next the Six Sigma team conducted process observations to get insight of the surgical process using "outsiders" with no experience in surgery, but experts in process improvements and human factors. The observers came back with several "aha" observations. The Six Sigma team also used the insight in identifying the various pathways that could result in a retained foreign objects event. The fault tree analysis was then validated using the historical events to ensure that there was no blind spot left. The probabilities of various pathways were computed to develop effective intervention strategies.

Based on the process observations, the Six Sigma team developed a list of "process variables" that by themselves would not be an issue, but when occurred collectively could interrupt the process flow (for example the number of phone calls to the OR, the number of times the staff need to get additional supplies, staff changes, etc.). The Six Sigma team then used this checklist for a month to collect data on the frequency of these interruptions.

In Conclusion of the Measure Phase of the Retained Foreign Objects Project

Retained foreign objects occur infrequently, but every time an event or near miss happens, the staff are deeply disheartened. The traditional way of tracking retained foreign objects (number of retained foreign objects by month or by quarter) is unreliable since one could go several months without a retained foreign objects event and not be sure if it was due to any planned intervention or by chance alone. The team researched an appropriate process improvement tool and decided to plot using G-chart, which tracks the days between events. This process improvement tool is more responsive to tracking changes made to a process.

Armed with this information, the team entered the Analyze phase of the Six Sigma DMAIC model, which I will cover in the next column.