For those who design, manufacture, or test electromedical equipment, 60601-1 is one of the most important safety and performance standards in AAMI’s portfolio of industry standards. It is referenced so often in the daily work of medical device engineers that AAMI plans to offer this updated standard in a pocket version.
60601-1 deals with medical devices that are intended to: 1) diagnose, treat, or monitor a patient under medical supervision; 2) make physical or electrical contact with the patient;
3) transfer energy to or from the patient; and/or 4) detect such energy transfer to or from the patient. Examples include battery-operated thermometers, external defibrillators, MRI and other imaging systems, endoscopes, patient monitors, and infusion pumps.
responsible for 60601. Sidebottom has been part of the drafting team for 60601 since work started on the third edition in 1995. Dave Osborn is senior manager of international standards and regulations for Philips Healthcare. He, too, has been closely involved with 60601 for a number of years.
What makes edition 3.1 of 60601 unique?
Sidebottom: Amendment 1 made significant changes to how we address risk management and essential performance. Edition 3.0 introduced these concepts into IEC 60601-1. Now, we have several years of experience using the standard, and seeing how it is used in the regulatory process. Plus, the state of the art is always moving forward, never a stable target. The standard needed to keep pace.
Osborn: The third edition expanded the mechanical testing requirements, and the requirements weren’t as polished as they needed to be. Edition 3.1 introduced a major update to the mechanical testing.
Why was edition 3.1 four years in the making?
Sidebottom: These were major changes and had to be consid- ered carefully to be sure we were actually improving the standard’s requirements.
Osborn: We also had some major clean-up work to do with about 80 individual items that needed to be updated. It takes time to get this right. Plus, the work is done by a consensus process that ensures all perspectives are heard and considered along the way.
Sidebottom: Also, some new standards came out after the third edition was published in 2005 that needed to be taken into consideration, such as software and usability. Those standards didn’t exist when we worked on the prior edition.
Why were changes made to the risk management areas of the standard?
Sidebottom: Risk management was the biggest area for deep analysis. We cut by about 20% the number of references to risk management where they weren’t needed because the standard already contained an objective way of assessing risk.
Osborn: 60601 is intended to show that your product design meets certain safety elements. These are the parts of the risk management process that you need to have in place to demon- strate that you applied appropriate risk management during the product design. There are other aspects of risk management that are addressed in other standards, such as post-market surveil- lance. 60601 was never intended to address risk beyond product design, and the new edition makes that clearer.
Sidebottom: The German participants on the committee did a detailed assessment of what parts of the standard needed to address risk, and where risk was already addressed in other objective criteria.
The standard addresses critical safety issues, including electri- cal shocks, and mechanical hazards, such as pinching, crushing, and breaking.
With the recent publication of Amendment 1 to the third edition of 60601, AAMI News spoke with two industry leaders who played a key role in its development.
Chuck Sidebottom is the director of standards for Medtronic. He also serves as secretary of the IEC subcommittee that is
Did these changes de-emphasize the importance of risk management?
Sidebottom: Not at all. There are still over 100 references to risk management in the standard, so it remains a central element. We essentially eliminated duplication and areas where there was no value add to the requirement.
Osborn: Here’s an example. The standard requires exposure to a high humidity environment for 168 hours. The earlier standard suggested that if the device was going to be exposed to high humidity for extended periods, you would do a risk
management assessment. There was no added
value to this requirement when the standard
already required exposure to a high humidity
environment for 168 hours. The device isn’t going
to get any wetter if it is soaked for 250 hours
instead of 168, and there was no objective way to
assess how much extra exposure would tell you anything mean- ingful. The original language was intended to give the manufacturer flexibility to reduce the time from 168 hours based on risk assessment, not intended to require even more time. It added complexity and confusion unnecessarily.
What about the requirements for essential performance?
Osborn: In the third edition, we thought we had made essential performance and basic safety mutually exclusive, but some people read the standard differently and that created confusion in the market.
Sidebottom: I like to illustrate the difference using the “brick model.” A device that becomes an inanimate object when it fails (a brick) is OK as long as it doesn’t fall on the clinician’s foot or land on the patient’s head. However, that’s clearly not good enough. If an external defibrillator doesn’t deliver enough energy to the patient, then the patient is at risk. That’s essential performance.
Osborn: Here’s another example. Insulation has performance; it creates a barrier related to current flow. Is that essential performance? No, it is not intended to be that, but some people interpreted the standard by blurring the line between essential performance and basic safety. This point was not explained clearly in the third edition. One of the objectives of Amendment 1 was to make that distinction clearer.
Sidebottom: We’re talking about the thought process that a manufacturer needs to go through to figure out what is the essential performance of the device. The third edition simply said that the manufacturer has to identify the essential performance. Now, subclause 4.3 outlines the thought process the manufacturer needs to go through beginning with the performance of the clinical functions of the equipment or system.
At the end, if the manufacturer decides that risk control meas- ures need to be implemented because loss or degradation of the performance of a clinical function would result in an unaccept- able risk, then that performance is “essential performance.”
Osborn: I think the least understood concept in the whole of the prior edition was the use of essential performance. That needs to become more second nature to manufacturers. Hopefully, with Amendment 1 we have made important progress to make that more understandable.
What is the difference between test requirements and risk management?
Osborn: 60601 is a horizontal standard that covers a whole class of medical devices. Some things are easy to test, such as leakage currents. It’s impossible, though, to write tests for everything.
For example, there is a spill test. You spill liquid on the equipment to make sure nothing that is safety critical gets wet, like bridging insulation. Where you spill a liquid and how much
you spill depends on the individual piece of equipment, where it’s used, how it’s used, and the like. So, you have to do a risk analysis to figure out what’s the worst case for your particular situation and then that tells you what and where to pour the liquid. It’s going to be different for a pencil thermometer than for an anesthesia machine.
A pencil thermometer is not likely ever placed under an IV bag that can leak or burst, whereas that is an anticipated risk for an anesthesia machine.
What else changed in the standard?
Sidebottom: Some new safety requirements were added from Europe’s machinery directive so that the standard would continue to be as comprehensive as possible in demonstrating conformity with European regulatory requirements.
For example, there is a requirement in the machinery directive that if you have a fixed piece of equipment with some sort of main disconnect (i.e., a switch on the wall to disconnect the power), that disconnect switch has to have a way to be locked in the open position. That way, if someone is working on the equipment someone else can’t switch it on again. That is a safety considera- tion for the person who is servicing the equipment. If you have an X-ray machine that is running off of three phase, 100 kilowatt source, you don’t want someone to close that switch while someone else is working on it or that individual could be electro- cuted. This would only apply to large, fixed installations. As a practical matter, it was probably being done this way anyway. Now, it’s part of the standard.
Will this be the final edition of 60601?
Osborn: Never! A few companies are already raising questions about certain aspects of the standard. That’s why it’s important for everyone to be at the table and to pay attention when standards are in development. These standards become part of the regula- tory process for companies. The time to assess whether a new requirement or test can be done effectively, efficiently, and at a reasonable cost, or whether something new actually improves basic safety or essential performance, is while the standard is under development.
Sidebottom: Each new version of the standard introduces improvements over the last version. This amendment has more than its share of significant improvements. Does that mean it is static? No. We’ll be back at this again as the state of the art continues to move forward and we live with the standard for