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Root Cause Analysis for Software-based Medical Devices

Of all the kinds of problems that medical device manufacturers face, complaints are clearly the most important. This is because complaints can represent potential gaps in your knowledge of how your customers use your devices. For software-based medical devices, complaints may be indicative of deficiencies in your software development, validation, manufacturing, or setup processes. Complaints can often result in disruptive, expensive, and unplanned software releases.

When complaints in software-based medical devices are not fully understood, they can result in poor solutions that often create more problems than they solve. Nothing frustrates customers more than a supplier who is unable to resolve problems quickly and correctly.

Traditional Root Cause Analysis has been routinely used to investigate the cause of major disasters including:
  • Airline crashes
  • Space Shuttle accidents
  • Chemical and nuclear plant disasters
An effective Root Cause Analysis process helps:
  • understand causes of customer complaints
  • understand the what, the why, and the how…
  • reduce rework by preventing recurrence
  • identify process weaknesses
  • improve customer satisfaction

For software-based medical devices, the traditional Root Cause Analysis Process has been adapted to accomodate development processes typically used to develop medical-device software.


Root Cause Analysis Process Overview

The Root Cause Analysis Process consists of investigating, understanding, and categorizing underlying root causes of observed events. It is best performed by a small cross-functional team and is easily incorporated into your Complaint Handling Process.

The Root Cause Analysis Process includes a detailed analysis based on gathering factual information obtained from:

  • Available documents and records
  • Interviews with staff and customers
  • Brainstorming sessions with staff

The Root Cause Analysis Process uses simple tools including:

  • Why Trees
  • Pareto Analysis

An effective Root Cause Analysis Process helps determine appropriate and effective corrective actions by identifying both an Immediate Corrective Action (what should be done today to resolve the complaint) and Long Term Corrective Action (what should be done to prevent recurrence).

In applying this Root Cause Analysis Process, the Team starts with a specific complaint and asks:

  • What is it about the way we operate that allowed this to occur?
  • What is it about the way this customer used our device that caused this to occur?
Most root causes are found in the way we operate. That includes:
  • Who does what?
  • How things get done?
  • Why we behave way we do?

The Team asks questions about "Who does what", "How things get done", and "Why we behave the way we do", in order to identify factual information that can be helpful in identifying real root causes.

In asking these questions, the Team uses a tool called the Why Tree. Why Trees are similar to Fault Trees in that the complaint is placed at the top. We then ask "Why did this happen?" and start drilling down into "Who does what", "How things get done", and "Why we behave the way we do". At each level, the Team continues to ask "Why" - usually at least five times (though for simpler problems, less than five Whys may suffice).

The following illustrates a partially completed Why Tree for a simple problem:

Why Tree

Answers to Why questions may need to be determined from documents (like Functional Specifications, Test Plans, User Manuals, etc.), from records (like test results, manufacturing records, etc.), from interviews with staff and customers, and from brainstorming sessions.

The information shown in green circles on the Why Tree example represents probable root causes. The Team reaches consensus on the most probable root cause(s). Often, there will be more than one root cause.

Using the Why Tree, the Team develops an Immediate Corrective Action (which could be a workaround, hot fix, patch, new CDs, new doc, etc.). The team also identifies effectiveness checks that can determine if the Immediate Corrective Action, once implemented, has effectively resolved the complaint.

Once the Immediate Corrective Action is implemented and the effectiveness checks are satisfactory, the Team decides if a Long Term Corrective Action is needed. A Long Term CA would be appropriate if the root cause points to systemic problems. If so, they begin to develop a Long Term Corrective Action. The Team does this by:

  • Reviewing existing processes and procedures
  • Identifying process weaknesses directly related to root cause
  • Identifying potential process and procedure changes
  • Identifying long term effectiveness checks

Once the team has competed work on the Long Term Corrective Action, it can be presented to Management and implemented. The team then collects data to determine if long term effectiveness checks are satisfactory.


Intended Audience

The intended audience for this workshop includes QA Staff, Complaint Handling Team, Software Development, and Technical Support. Project Teams should attend this training together as a team, if possible. Once a team has been trained, I frequently facilitate the first few meetings where the Root Cause Analysis Process is applied.


Tailoring

tailor This workshop can be tailored to meet your specific needs and development process.

Call for details...




For further information,

call Steve Rakitin at 508.529.4282

or e-mail him at steve@swqual.com


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Copyright ©2008 Software Quality Consulting, Inc. All rights reserved.

Updated January 2008