Software in Medical Devices, by MD101 Consulting

One the latest version of the draft MDR (they're not all public, that' work in progress) can be downloaded on the European Council website.

Standalone software definition removed

Compared to the early versions of 2012, the MDR versions of mid 2015 and after don't include the term standalone software in the definition of active medical device.

Before, version of 2012

‘active device’ means any device, the operation of which depends on a source of electrical energy or any source of power other than that directly generated by gravity and which acts by changing the density of or converting this energy. Devices intended to transmit energy, substances or other elements between an active device and the patient, without any significant change, shall not be considered to be active devices.
Stand alone software shall be considered an active device.

Text set bold here for emphasis

After, version of 2015

‘active device’ means any device, the operation of which depends on a source of energy other than that generated by the human body for that purpose or by gravity and which acts by changing the density of or converting this energy. Devices intended to transmit energy, substances or other elements between an active device and the patient, without any significant change, shall not be considered to be active devices.

Consequences

When the version without standalone software was published, most of readers didn't notice the change or just think that the definition shouldn't be too specific. Specific definitions have the drawback to exclude peculiar cases from their scope.

But this is not the real consequence.

The authors of BSI white paper, who are kind of messengers of European Commission city of the gods, brought to us, mere mortals, the real consequence of this change.

Page three of the white paper, they say:

Standalone software is no longer classified as active medical device: revisit classification of software currently on the market as medical device and make gap assessment for additional technical requirements for software classified in higher risk class.

Standalone software is no longer classified as active medical device?

Standalone software is no longer classified as active medical device!

Computer science unplugged

OK, standalone software is not an active medical device. Let's unplug it!
That's possible to do your work unplugged, when you're a rock-star!
That's possible to do computer science unplugged, but that's not very useful in professional life!

Don't say his name

Or perhaps should we ask Harry Potter how to run software without electric power?
Or perhaps He-Who-Must-Not-Be-Named was removed from the definition?

Seriously:

Where does it come from?

This change seems to come from the situation where some kind of standalone software are put in class I with the current 93/42/CE directive, per rule 12, whereas they should be set in a higher class.
Hum, I thought that the implementing rule set in Annex IX 2.3 of the directive:

Software, which drives a device or influences the use of a device, falls automatically in the same class.

was there to avoid such situation.
We retrieve the same rule in the new MDR, with precision on independent software:

Software, which drives a device or influences the use of a device, falls automatically in the same class as the device.
If the software is independent of any other device, it is classified in its own right.

This new sentence in the implementing rule formalizes what manufacturers are already doing with the current directive.
Perhaps that wasn't enough and in some rare cases standalone software is set in class I whereas it should be in class IIa or IIb. But it doesn't explain the decision to remove standalone software from active medical devices.

Let's try some examples.

Drug dose calculator

A drug dose calculator uses patient's weight, average SOP2 and heart rate as input data. This is a standalone software medical device, for it uses patient data to compute a value intended to treat the patient condition.

Current MDD

Classification with the current medical device directive:

• Rule 1 : non-invasive device, Ok applicable,
• Rules 2, 3 and 4 : not applicable,
• Rules 5, 6, 7, 8 : invasive devices, not applicable,
• Ah ah, active devices, my software is an active device, let's see there rules:
  • Rule 9: active therapeutic devices intended to administer or exchange energy, not applicable,
  • Rule 10 : Active devices intended for diagnosis, not applicable
  • Rule 11 : All active devices intended to administer and/or remove medicines, we could say that it is applicable but no, this rule is made for devices like infusion pumps, not standalone software, this is probably the kind of situation that the change is trying to address,
  • Rule 12 : default rule, applicable,
• Rules 13 to 18 : special rules, not applicable.

Conclusion: drug dose calculator is in class I per rule 12.

Future MDR

Classification with rules in annex VII of the future medical device regulation:

• Rule 1 : non-invasive device, Ok applicable,
• Rules 2, 3 and 4 : not applicable,
• Rules 5, 6, 7, 8 : invasive devices, not applicable,
• Ah ah, active devices, my software is NOT an active device, rules 9 to 12 not applicable,
• Rules 13 to 23 : special rules, not applicable.

Conclusion: drug dose calculator is in class I per rule 1.
This is not very convincing.

If software drives or influence another device

If the drug dose calculator is used to, say, set the parameters of an infusion pump, it will take the class of the infusion pump: class IIb. The new MDR doesn't change the result.

Post-processing medical imaging software

A medical imaging software post-processes DICOM compliant data to produce new data to help physicians in their diagnostics. This is a standalone software medical device, for it uses patient data to compute new data intended to diagnose the patient's condition.

Current MDD

Classification with the current medical device directive:

• Rule 1 : non-invasive device, Ok applicable,
• Rules 2, 3 and 4 : not applicable,
• Rules 5, 6, 7, 8 : invasive devices, not applicable,
• Ah ah, active devices, my software is an active device, let's see there rules:
  • Rule 9: active therapeutic devices intended to administer or exchange energy, not applicable,
  • Rule 10 : Active devices intended for diagnosis, applicable, per bullet 3 intended to allow direct diagnosis,
  • Rule 11 : All active devices intended to administer and/or remove medicines, not applicable,
  • Rule 12 : default rule, not applicable as rule 10 is applicable,
• Rules 13 to 18 : special rules, not applicable.

Conclusion: medical imaging post-processing software is in class IIa per rule 10.

Future MDR

Classification with rules in annex VII of the future medical device regulation:

• Rule 1 : non-invasive device, Ok applicable,
• Rules 2, 3 and 4 : not applicable,
• Rules 5, 6, 7, 8 : invasive devices, not applicable,
• Ah ah, active devices, my software is NOT an active device, rules 9 to 12 not applicable,
• Rules 13 to 23 : special rules, not applicable.

Conclusion: medical imaging post-processing software is in class I per rule 1.
Bye bye notified body!

If software drives or influence another device

It is admitted that post-processing medical imaging software doesn't drive or influence the use of imagers. For example, software post-processing CT images is most of times in class IIa, even if the CT scanner is in class IIb.
The new definition in the future MDR doesn't change the conclusion on the application of this implementing rule.

Conclusion

It has to be agreed that we're missing something.
Trying to apply the classification rules of the future MDR, we reach the opposite, lower class, of what the regulator is seeking to obtain, higher class.

The published MDR versions are still drafts, they can change until the final version of the MDR. Let's hope that this will be clarified, either in the MDR, or in future MEDDEV guidances.


BTW, this post shouldn't stop you reading the BSI white paper. This is a top-level document on the consequences of the MDR.