IEC 60601-1-8 - When does an error message become an alarm signal?

shimonv

Quite Involved in Discussions
#1
Hi Guys,
If a medical electrical equipment includes a set of visual error messages on the screen to indicate some sort of error that could mean an hazardous situation does that mean it must comply with 60601-1-8? if so, most all ME equipment with a GUI must comply with this standard. Can someone please clarify?

Moreover, I looked at the standard and it's not clear to me if auditory ALARM is an imperative part of the alarm system. I'd appreciate input on that as well.

Perhaps another way to phrase the question would be: when does an error message becomes an alarm signal, and if so do you have to add auditory element to it?


Thanks!
Shimon
 
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Jean_B

Involved In Discussions
#2
The initiating definition is ALARM SYSTEM and ALARM CONDITION.

Note that the standard does not specify whether it needs an alarm, just requirements for when it is equiped with one. It also states it may fall within either protection as information for safety under A.1.2, which states "values of monitored variables" as information.

ALARM CONDITION refers to where: measurements (perhaps put through some logic model) are compared to the ALARM LIMIT to indicate where awareness and/or response is required to mitigate (potential) hazards and reduce (or prevent) harm (e.g. vitals, but could also be device characteristics). The A1 amendment makes this a bit clearer right in the definition, but it was already quite clear in the accompanying guidance to me.

ALARM SYSTEM is the part that deals with detecting the ALARM CONDITION, applying logic to determine what to do, and generating the ALARM SIGNAL which is appropriate.

This ALARM SIGNAL may be in any form (visual, audio or other (e.g. vibrate)) as appropriate to the urgency required based on the criticality of the condition.

Need a runner when that runner may be down the hall? Audio. Need someone to replace a waste bag within 2 hours when ½ hour rounds are performed, visual might do if usability shows low risk of missing it. AED battery problem? Might even want to go to telecommunication to a maintenance center besides visual or audio.

Often you would want to look at what the same type of device uses as an alarm, as that is what healthcare professionals are used to. It also relates to use-cycles (continuous like a hearing aid or respiration, a mandatory inspection step before use such as resterilization, grab and go AED, etc) and the speed at which degradation occurs versus opportunity/likelihood of detection before use.

Which measured parameters constitute an ALARM CONDITION is something that should roll out of your risk management.

So the core piece is: if you need someone (user/patient) to do something based on a measurement made by your equipment exceeding a limit set within your equipment to prevent (further) harm, this is applicable (if it is a medical device to begin with). If you indicate something, but push alarms away saying actions are still up to the user (more of an aid in this case, e.g. thermometer) be careful of what you claim as clinical efficacy and intended use.
 

shimonv

Quite Involved in Discussions
#3
Thank you Jean. It blends perfectly with the rest of my notes on this subject :)

In closing I am adding two summary points of my own:

1. If your device produces visual or audible signals with the intent to mitigate risk (reduce the probability of occurrence of harm) you are using an alarm system and it is highly recommended that you follow 60601-1-8.

2. This standard (over 80 pages) cover both visual and audible alarms, but the vast majority of the specifications are devoted to audible-alarm issues. Each alarm condition shall cause the generation of visual alarm signals, and if deemed necessary by risk assessment regarding the environment in which the alarm system is intended to be used, additional alarm signals shall be used. These additional alarm signals may be auditory, verbal, vibratory or produced by other means.


Cheers,
Shimon
 

noorain

Starting to get Involved
#4
Shimnov,
One of the notifying body said us, that if we wont call the signals as alarm rather refer them as warnings then we can ignore 60601-1-8. Any comments on this ?
 

Marcelo Antunes

Addicted to standards
Staff member
Admin
#5
Shimnov,
One of the notifying body said us, that if we wont call the signals as alarm rather refer them as warnings then we can ignore 60601-1-8. Any comments on this ?
Seems like a comment from someone who has no idea about the standard and risk management (and is trying to circumveit the requirement by using a concept in a wrong way).

The standard clearly says:"If the MANUFACTURER chooses as a means of RISK CONTROL to have the ME EQUIPMENT or ME SYSTEM notify the OPERATOR that a HAZARDOUS SITUATION can exist, then the ME EQUIPMENT or ME SYSTEM shall include an ALARM SYSTEM complying with this collateral standard for that purpose."

So, if you do that (chooses as a means of RISK CONTROL to have the ME EQUIPMENT or ME SYSTEM notify the OPERATOR that a HAZARDOUS SITUATION can exist), it has to have an alarm system. Warnings are also related to hazardous situations, but they are put on the on the manual.

In risk management terms, alarms are the second level of risk control, and warning are information for safety (third level).
 
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shimonv

Quite Involved in Discussions
#6
I agree with Marcelo.

noorain, I would like to point out the four things:

1. Many device manufacturers design their products with alarm system without calling it this way; they prefer to use terms like warnings or alerts.
2. It is unfortunate (or not) that many auditors, including some from reputable notified bodies, don't understand this standard and therefore don't challenge the manufactures.
3. Implementing this standard is no small thing. It effects the Instructions for Use, design input and design output documents.
4. What to do depends on where you are at with the product development, who the auditor is, risk level associate with the device etc. But the one fundamental fact remains: if your device produces visual or audible signals with the intent to mitigate risk you are using an alarm system, and it is recommended that you follow or at least consider to follow IEC 60601-1-8.


Shimon
 
#9
testing has to be done for alarm as per 60601-1-8. for this sound meter is required but it may catch environmental noise also. so if testing is done shielded room, this possibility may be eliminated. so is this shielded room is mandatory for going through the testing at manufacturing premises?
thank you for your interest.......
 

shimonv

Quite Involved in Discussions
#10
I am not experienced with in-house testing for 60601-1-8. However, I did not see in external lab reports for 60601-1-8 a reference for a shielded room.
Moreover, I found this text in the standard:
"Measure the drive signal of the audio transducer utilizing an oscilloscope or other suitable instrument to cover the frequencies and the RISE and FALL TIMES of the waveform. Verify the values of x, y, tb, tr, ts, tf and td in Table 3 and Table 4. Alternatively, acoustic measurements in an anechoic chamber are permitted."

It seems to me that a shielded room is not mandatory, but I advise you to verify this with a lab.

Cheers,
Shimon
 
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