How to Achieve Zero Retained Foreign Objects with DMAIC Part III

Previously, I discussed the Define and Measure phases of the retained foreign objects project. In this entry I will discuss the Analyze phase of the project.

Defining the Analyze Phase of the Six Sigma DMAIC Model

The Analyze phase is probably the critical phase of the Six Sigma DMAIC model process. The goal of the Analyze phase is to obtain a deeper understanding of the relationships between the various inputs factors identified (Xs) on the output (Y) that we are trying to improve with the Six Sigma project. This Analyze phase helps in gaining greater insights of the sources of waste, variation and imbalances in the system. After the Analyze phase, the Six Sigma team should be able to articulate the "whys" and the "hows" for the problem they are charged to solve. After the Analyze phase, the Six Sigma team will be able to find solutions to bridge the gap between the current performance (which is not desirable) and future state (desired state within the given time for the project).

Six Sigma tools commonly used in the Analyze phase include: five whys analysis, cause and effect diagram, brainstorming, affinity diagram, detailed flow charts, Pareto charts, scatter plots and regression analysis. Tools such as the five whys and cause and effect are utilized to identify the sources of variation, while Pareto charts are used to identify the vital few factors (Xs) from the many factors that affect the Critical output (Y). Regression analysis, scatter plots and other tools are useful to determine the influence of independent variables (Xs) on the output factor (Y).

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

For the retained foreign object mitigation project, we analyzed the data poring over the sentinel events database for events and near misses. The root cause analysis performed was reviewed to identify any common themes in these events. The Six Sigma team decided to perform a painstaking analysis using the top-down fault tree analysis approach to identify various pathways that could lead to a potential retained foreign objects event. The model was then tested against the events from sentinel events. This served two purposes: one to validate the model and identify potential gaps in the model, and second to serve as an excellent visual to stakeholders on how complex and daunting the task could be given the complexity of the man, machine and environment interface in the operating room to eliminate retained foreign objects.

The in-depth analysis of the retained foreign objects characteristics indicated that, contrary to what is cited in the literature, our experience did not show any correlation to emergency procedures, unplanned changes in procedure and higher body mass index as high risk factors. Some interesting facts emerged. The majority (62 percent) of the retained foreign objects occurred after the "counts" were considered correct at the end of the surgery. The only reason these were caught was because of the Mayo Clinic Rochester’s policy of performing X-rays (survey film) on all patients when any body cavity is operated upon, irrespective of the count. Communication lapse was the most leading factor in these events. Pareto analysis was used to identify the common sources of retained foreign objects. The defects per million opportunities were calculated (the number of opportunities per surgery exceeds 200, but we used a conservative 25 opportunities to get baseline) as well as the sigma level and compared it to other institutions of similar size in the State of Minnesota.

With the insight into the sources of variation, deeper understanding of the characteristics of retained foreign objects in the institution, a better understanding of the key variables that contribute to retained foreign objects (communication, count accuracy, disruptions in the OR, etc.), the Six Sigma team started the plans for piloting ideas. The ideas were generated using brainstorming techniques (another common tool in the Analyze phase) for each of these areas and narrowed down based on hypothesis and expert knowledge in the field.

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

The Analyze phase helps the team to develop innovative and often key ideas to pilot after thorough and detailed analysis of the data. This structured problem solving helps the Six Sigma teams uncover true causes of the variation and help them prioritize the implementation plan. In the next column, I will discuss the Improve phase of the Six Sigma DMAIC model for the retained foreign objects initiative.