Clinical Investigation
Evaluation of Safety in a Radiation Oncology Setting Using Failure Mode and Effects Analysis

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Purpose

Failure mode and effects analysis (FMEA) is a widely used tool for prospectively evaluating safety and reliability. We report our experiences in applying FMEA in the setting of radiation oncology.

Methods and Materials

We performed an FMEA analysis for our external beam radiation therapy service, which consisted of the following tasks: (1) create a visual map of the process, (2) identify possible failure modes; assign risk probability numbers (RPN) to each failure mode based on tabulated scores for the severity, frequency of occurrence, and detectability, each on a scale of 1 to 10; and (3) identify improvements that are both feasible and effective. The RPN scores can span a range of 1 to 1000, with higher scores indicating the relative importance of a given failure mode.

Results

Our process map consisted of 269 different nodes. We identified 127 possible failure modes with RPN scores ranging from 2 to 160. Fifteen of the top-ranked failure modes were considered for process improvements, representing RPN scores of 75 and more. These specific improvement suggestions were incorporated into our practice with a review and implementation by each department team responsible for the process.

Conclusions

The FMEA technique provides a systematic method for finding vulnerabilities in a process before they result in an error. The FMEA framework can naturally incorporate further quantification and monitoring. A general-use system for incident and near miss reporting would be useful in this regard.

Introduction

A safe and effective radiotherapy treatment necessarily consists of treating the correct tissue in the correct patient with the correct dose. This is to be accomplished in one of the most complex settings in healthcare—one that is steadily growing more complex. Reported error rates have ranged from 0.06% to 4.66%, depending on how errors are quantified 1, 2, 3, 4, 5. Although most of these errors are minor and treatment can be adjusted to allow effective therapy, there is a strong incentive to reduce these rates even further, given the potentially catastrophic nature of an error.

The discipline of radiation oncology has many well-established methods in place to prevent errors or to mitigate their effects. Examples include independent checks of delivered dose via diodes on the patient's skin (6), weekly review of patient films and charts, and standard quality assurance measures designed to uncover more systematic errors (7). What is less well established in the field of radiation oncology is the view of systems-wide safety and the associated methods for systematic risk analysis and improvement.

Systematic risk analysis is a powerful tool that can help to identify vulnerabilities in a specific clinic and to suggest where resources might be concentrated for the most significant impact. Such methodologies are now in regular use in other healthcare disciplines: for example, to prevent chemotherapy errors (8), to improve performance in trauma (9), or to improve the design and use of equipment (10). The Joint Commission on Accreditation of Healthcare Organizations has also called for regular prospective safety analyses (11).

Here we report our experience with one particular safety improvement methodology, failure mode and effects analysis (FMEA). The FMEA technique is a well-established tool for safety analysis and improvement (12). It is widely used in manufacturing, where many vendors use it to fulfill the requirements for prospective risk analysis by the Food and Drug Administration (21 CFR 820) and the Internal Organization for Standardization 9000 standards. The FMEA technique is also beginning to be used in other disciplines in healthcare 8, 9, 10. The goal of this article is to present an overview of FMEA as specifically applied to a radiation oncology clinic. A similar report by American Association of Physicists in Medicine Task Group 100 has appeared, which describes a basic outline of FMEA and two example applications in radiation oncology (13).

Section snippets

Methods and Materials

The initial analysis presented here was performed over a 3-month period, starting in January 2007. The steering committee consisted of 11 members, representing a cross-section of department staff including administrators, nurses, clinical research coordinators, radiation therapists, physicists, information technologists, resident physicians, and attending physicians. The committee was further assisted by staff from the Johns Hopkins Center for Innovation in Quality Patient Care.

A first step in

Results

Our process map consisted of 269 separate nodes, each indicating an action to be taken or information to be manipulated in some manner (Fig. 1). The map falls naturally into four categories: patient consult, simulation, treatment planning, and treatment. An example of one section of the map is shown in Fig. 2. Note that this section is part of a much larger map and represents approximately 10% of the total number of nodes. Nevertheless, even with such a large process map we emphasize that the

Discussion

A systematic consideration of factors related to reliability and safety can reduce error rates. This is germane to the generally recognized need to improve safety in healthcare (20). Anesthesiology is an often-cited success story in this regard. By actively using safety measures, mortality rates have been reduced by more than a factor of 20 in the last 25 years (21). A handful of studies have measured the error rates of delivering radiotherapy treatment fields 1, 2, 3, 4, 5. There is a wide

Acknowledgments

The authors thank the following individuals for their active participation in this failure mode and effects analysis process: Ruth Bell, R.T.T., Daryl Carson, B.S., Kelly Cavallio, J.D., Timothy Chan, M.D., Andrea Cox, R.N., Marsha Goldberg, R.T.T., Mary Ellen Holland-Callender, R.T.T., Richard McCarthy, B.S., and members of the Johns Hopkins Center for Innovation in Quality Patient Care.

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