Patient Monitor Viewing Distance Usability Requirements

[LiamD]

Hi,

Are there any usability requirements that define or recommend the acceptable distance that values can be viewed on a screen of a patient montor?

Thanks,
Liam

 

[Mikishots]

Hi,

Are there any usability requirements that define or recommend the acceptable distance that values can be viewed on a screen of a patient montor?

Thanks,
Liam

Most modern patient monitors have adjustable font size. The idea is to set the text to be legible at the distance required; if you can't read it, either increase the font size until you can or simply move closer. If you can't move closer, the monitor is of no use.

 

[LiamD]

Thanks Mikishots. Yes there are a number of ways that I can change the fonts.

I wanted to know if there were any regulatory/standards/guidance which define the legibility/readability of important values.

 

[Mikishots]

Thanks Mikishots. Yes there are a number of ways that I can change the fonts.

I wanted to know if there were any regulatory/standards/guidance which define the legibility/readability of important values.

Define "important" values. I'd say that this would depend on the patient's condition and is solely the call of a physician or nurse.

 

[somashekar]

Thanks Mikishots. Yes there are a number of ways that I can change the fonts.

I wanted to know if there were any regulatory/standards/guidance which define the legibility/readability of important values.

Positioning of the monitor at a suitable height to be able to operate and connect / disconnect safely, keeping it within the reach of the monitor cable and sensors length that connects to the mains as well as the patient is considered by the hospital / ICU / OT design and layout. From this position the doctor / nurse must be able to read perhaps standing at the diagonally opposite end of the patient bed. How much this could be ?
Perhaps 8 feet, 10 feet ? or around that. This must be acceptable as a useability input requirement.

 

[LiamD]

Thanks Somashekar. These are all good points that you highlight.

My fundamental question is regulatory/standards/guidance which define the legibility/readability of important values. Important values would be defined by the intended use of the instrument. For example, the 60601-1-8 alarms standard defines a viewing distance for visual ALARM SIGNALS.

If a visual indicator is necessary for the OPERATOR to identify the equipment or part of the equipment that requires OPERATOR response or awareness, at least one visual ALARM SIGNAL shall be provided that:

a) indicates the priority of the highest priority ALARM CONDITION; and
b) can be perceived correctly at a distance of 4 m from the ALARM SYSTEM.

Is anyone aware of regulatory/standards/guidance which define the legibility/readability of important values.

 

[somashekar]

Thanks Somashekar. These are all good points that you highlight.

My fundamental question is regulatory/standards/guidance which define the legibility/readability of important values. Important values would be defined by the intended use of the instrument. For example, the 60601-1-8 alarms standard defines a viewing distance for visual ALARM SIGNALS.



Is anyone aware of regulatory/standards/guidance which define the legibility/readability of important values.

I guess if there is any such regulatory/standards/guidance which define the legibility/readability of important values, it would have been mentioned within the 60601-1-8...

 

[Pads38]

I have had a quick look and haven't found anything directly but from the general standard you get

7.1.2 Legibility of Markings
....shall be clearly legible...
....the viewpoint is the intended position of the operator...
...the illuminance is the least favourable..in the range of 100lx to 1500lx..

7.1.1 Usability of the markings
The manufacturer shall address the...risk of poor usability..associated with the markings..

I have had a look at some of the particular standards (the Part 2 standards) where one might expect those clauses to be modified by a particular requirement but haven't found anything. I don't though have a copy of -2-49 (multifunction patient monitoring equipment) which might be the most relevant.

Without a direct requirement I think it is up to you, as manufacturer, to define the likely use scenario (so where and how is your equipment designed to be used) and use risk analysis to identify what information must be identifiable from, say, the end of the bed and what may be legible only from up-close.

 

[Marcelo]

It´s really up to you because it depends on intended users.

IEC 60601-1 third edition has a requirement on legibility of markings which could be used for other information.

AAMI HE 75 has some guidance, for example, a table with Recommended character height and corresponding font sizes for various reading distances.

Anyway, those can be found in a lot of human factors books.

 

[Mikishots]

It´s really up to you because it depends on intended users.

Thank you for that - I was beginning to think that the point just wasn't going to get across.