ARTICLE FOCUS:

• Expanding the role of safety
• Applying risk management
• Testing early in the product life cycle

Figure 1a. A painting by Hieronymus Bosch circa 1488–1516, shows primitive tools used for trepanation compares sharply with modern computer-to-brain interfaces, such as BrainGate shown in Figure 1b, developed in 2008 by Cyberkinetics and Brown University (b).

When biomedical engineers first begin to conceptualize a new medical device, verification and validation (V&V) is usually at the forefront of their thoughts. They want to start the effort well by making sure that they have the right tools and processes in place for "building the product right," and they want to be able to conclude their efforts by demonstrating that they've "built the right product" for their customers. Standards have always played a role in verification and validation, but the introduction of IEC 60601-1's third edition deals with the V&V of increasingly complex medical devices in a whole new way.

The complexity of medical devices has grown in almost unfathomable leaps and bounds from the likes of primitive tools used for trepanation, as shown in the painting in Figure 1a by Hieronymus Bosch circa 1488–1516, to the likes of modern computer-to-brain interfaces, such as BrainGate (see Figure 1b), developed in 2008 by Cyberkinetics and Brown University.

Arguably one of the most influential technologies in driving system complexity has been software. Software can introduce a level of product capability that begins to approach that of the human brain, and product complexity that begins to parallel that of human thought processes. If not designed with great care, software can also induce system failures, such as erratic operation or incorrect processing of data, which have uncanny parallels to conditions of the human brain such as schizophrenia and bipolar disorder.

While many debate the definition of software, the medical device community has agreed that a software product, which may by itself be considered a medical device, is a "set of computer programs, procedures, and possibly associated documentation and data."¹ Just as human physical and emotional health are intertwined and must be managed together, as system complexity grows, managing medical device complexity holistically becomes paramount to ensuring system health. Addressing both systematic flaws and random faults (e.g., short circuit caused by conductive pollution) becomes one of the primary means of ensuring that the medical device will do what it is intended to do and not do that which is not intended.

Expanding safety, minimizing defects
As stated in its introduction, the third edition of IEC 60601-1 has changed in some very fundamental ways: First, the concept of "Safety" has been broadened from the "Basic Safety" considerations in the first and second editions of IEC 60601-1 to now include "Essential Performance," (e.g., the accuracy of physiological monitoring equipment). The second change is that in specifying minimum safety requirements, provision is made for assessing the adequacy of the design "process" when this is the only practical method of assessing the safety of certain technologies such as programmable electronic systems.² Finally, the organizational structure of the standard itself has changed in a manner that reflects the importance of software V&V in the context of the overall product. Rather than existing as a collateral standard (formerly IEC 60601-1-4), software requirements are now embedded directly into the general requirements of the third edition of IEC 60601-1 via Clause 14. This structural change establishes a clearer path for addressing the potential role of software in mitigating basic safety issues, such as fire and electric shock as well as for addressing the role that software plays in Essential Performance (i.e., the safety-related behaviors or functional capabilities of the medical device).