The Cove Business Standards Discussion Forums
Go Back   The Elsmar Cove Business Systems and Standards Discussion Forums > > >
Forum Username

Elsmar Cove Forum Visitor Notice(s)

Wooden Line

IEC 60601 - Limits of agreement as Essential Performance

Monitor the Elsmar Forum
Courtesy Quick Links

Links Elsmar Cove visitors will find useful in the quest for knowledge and support:

Jennifer Kirley's
Conway Business Services

International Quality Services

Marcelo Antunes'
SQR Consulting, and
Medical Devices Expert Forum

Bob Doering
Bob Doering's Blogs and,
Correct SPC - Precision Machining

Ajit Basrur
Claritas Consulting, LLC

International Standards Bodies - World Wide Standards Bodies

AIAG - Automotive Industry Action Group

ASQ - American Society for Quality

International Organization for Standardization - ISO Standards and Information

NIST's Engineering Statistics Handbook

IRCA - International Register of Certified Auditors

SAE - Society of Automotive Engineers

Quality Digest

IEST - Institute of Environmental Sciences and Technology

Some Related Topic Tags
definitions, iec 60601 - medical electrical equipment
Thread Tools Search this Thread Rate Thread Content Display Modes
  Post Number #1  
Old 10th July 2018, 07:12 AM

Total Posts: 7
Question IEC 60601 - Limits of agreement as Essential Performance

Hi All,

Supposedly I have a medical device that measures and logs respiratory rate (it is not defined as an Alarm Monitor).

The efficacy of the device in clinical testing is determined with respect to a gold standard measurement (i.e by comparing the respiratory rate measured by the test device an a gold standard method). This is commonly done using a statistical method called BLAND ALTMAN which, in short, provides one with the "mean bias" between the two methods and the limits of agreement (i.e. the limits where 95% of the data will fall with 95% confidence)

For IEC 60601 one must define the Essential Performance which is the clinical function where loss or degradation beyond the limits results in an unacceptable risk.
During the safety and EMC testing we use a simulator that simulates respiration in a constant rate and we measure the respiration rate.

My question is if it is logical to use the same parameter used in the clinical testing - "limits of agreement = +/-X" as the essential performance, thus preforming a statistical post-analysis of the data collected during the safety&EMC tests making sure it does not exceed the pre-defined limits +/-X.

Thanks in advance.

Sponsored Links
  Post Number #2  
Old 10th July 2018, 06:00 PM

Total Posts: 1,167
Re: IEC 60601 - Limits of agreement as Essential Performance

Not to sidetrack the question but if the device did fail, what is the unacceptable risk that would be realized? (The main point being that some devices do not have Essential Performance.)
  Post Number #3  
Old 11th July 2018, 04:08 AM

Total Posts: 7
Re: IEC 60601 - Limits of agreement as Essential Performance

That is actually a good question.
Since respiratory rate is a vital sign and the device is intended for hospitals , it must be defined as a medical device.
The risk here is that in a case of performance degradation, the medical staff would receive an unreliable clinical information. Although, in the current scenario it would be used in conjunction with other type of clinical information, it still might result in an unsuitable medical care.

The issue I have raised is due to the fact that we must define limits of "accuracy" for the EP of measuring respiratory rate.
Since for our device there is no guiding standard as opposed pulse-oximeter ( IEC 80601) which defines the accuracy, the question is what type of "accuracy" estimate would be most reasonable/accceptable to use.

If, for example, we say that the respiratory rate accuracy is +/- 10% then the immediate question would be how to calculate this, as we might get up to 60 respiratory rate value per minute. Does each value must be +/-10% with respect to the reference or would it be more logical to use a statistical analysis (like i suggested or other) over the duration of the test (e.g. EMC )
  Post Number #4  
Old 11th July 2018, 07:42 PM
Peter Selvey

Total Posts: 907
Re: IEC 60601 - Limits of agreement as Essential Performance

While there is a lot about "essential performance" which is nonsensical, there's actually a common sense bit at the end of the clause that says:

"Where this standard requires that ESSENTIAL PERFORMANCE is to be maintained following a particular test, compliance is checked by inspection and, if necessary, by functional test(s) that demonstrate the MANUFACTURER'S specified limits are maintained or the ME EQUIPMENT or ME SYSTEM transitions to a safe state as defined by the MANUFACTURER."

So, for example a water proof test shows that no water got anywhere near the electronics involved with measurement of respiration, then no need to test essential performance.

On the other hand another test might feasibly affect the electronics (say low or high temperatures?) you could devise a simulator test that gives reliable results that would allow you to detect if the electronics has been affected.

In other words, you can tailor the "functional tests" to suit. It does not need to be the full evaluation (e.g. multiple samples, statistical analysis) every time the standard calls out essential performance.

This does though highlight one huge oversight in the standard in that there is no baseline test to establish essential performance in a set of reference conditions. In practice, a manufacturer would do the more detailed baseline test first and then start to throw various "stress tests" such as EMC, water ingress, normal temperatures, storage, vibration, ageing, thermal shock, defib etc, and verify that nothing changed, usually by inspection or simplified tests based on the nature of "stress" being applied.

Also, in the case of a simplified test, it is normal to run the that test first to set a baseline, and possibly apply stricter limits than are defined in the essential performance, in order to detect whether the "stress" caused any variations. A fail result for this stricter limit should either trigger more detailed tests or investigate/eliminate the cause of the variation.

Anyway, without establishing a baseline the whole logic of tailoring the test to suit falls down. Even the above example of the waterproof test falls down logically if essential performance was never established in the first place.
Thanks to Peter Selvey for your informative Post and/or Attachment!

Lower Navigation Bar
Go Back   The Elsmar Cove Business Systems and Standards Discussion Forums > > >


Visitors Currently Viewing this Thread: 1 (0 Registered Visitors (Members) and 1 Unregistered Guest Visitors)
Thread Tools Search this Thread
Search this Thread:

Advanced Forum Search
Display Modes Rate Thread Content
Rate Thread Content:

Forum Posting Settings
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Emoticons are On
[IMG] code is On
HTML code is Off

Similar Discussion Threads
Discussion Thread Title Thread Starter Forum Replies Last Post or Poll Vote
IEC 60601-1 and Essential Performance Kunal Deshpande IEC 60601 - Medical Electrical Equipment Safety Standards Series 5 24th July 2018 01:05 AM
IEC 60601-2-44: 202.101 Immunity Testing of Essential Performance dhughessr IEC 60601 - Medical Electrical Equipment Safety Standards Series 0 8th September 2017 01:35 PM
"Potential" Essential Performance in IEC 60601-2-54 (Definition) ltcmff IEC 60601 - Medical Electrical Equipment Safety Standards Series 9 13th October 2016 10:37 PM
Essential Performance in IEC 3rd edition of the 60601-1 aeropel IEC 60601 - Medical Electrical Equipment Safety Standards Series 5 21st May 2012 04:54 AM
Technical Agreement for the CE Mark - Essential Requirements Checklist Azu2008 EU Medical Device Regulations 7 14th July 2008 08:25 AM

The time now is 08:27 AM. All times are GMT -4.
Your time zone can be changed in your UserCP --> Options.

Misc. Internal Links

NOTE: This forum uses "Cookies"