Identifying Applied Parts

[MedWizard]

Hello,

I'm very pleased to join you on this unique forum and would like to start of with a thread that hopefully can help me and others distinguishing between APPLIED PARTS, ACCESSIBLE PARTS, ENCLOSURE and other parts of ME EQUIPMENT in accordance with 60601-1. The standard definition is as follows:

* APPLIED PART
part of ME EQUIPMENT that in NORMAL USE necessarily comes into physical contact with the PATIENT for ME EQUIPMENT or an ME SYSTEM to perform its function

The 60601-1 standard provides a good deal of information and detail on the matter in example images and subclause 3.8 but leaves out some basic definitions. So, to the question:

Let’s consider medical equipment operated by the patient in home settings, digital pill organizer, IR thermometer or a medical alarm clock. All of the items can be said to have a battery and a mains connected charger. Would following parts of the equipment, which are all touched during NORMAL USE be considered APPLIED PARTS according to 60601-1?

1. Power cord and plug.
2. External power supply.
3. On-off button.
4. Settings buttons.
5. Parts of enclosure that are held during normal use.
6. Parts of the transport bag in which the device is transported.

My general judgement is that while the listed parts can be argued to fall under definition of APPLIED PART, the standard is primarily describing applied parts as parts that are in constant contact with the patient or are touched in order to perform a clinical function. This is especially clear in subclause 3.8. My gut feeling is to argue that neither part on the list is APPLIED PART, especially if Risk Management shows that the parts are not a cause of potential harm.

Best Regards,

MW

 

[Tidge]

All of the parts you enumerated above come in contact with the OPERATOR and require means of operator protection.

Among the distinctions between an OPERATOR and a PATIENT is the concept that a patient may not be aware that the medical device is being applied to them, whereas there is a presumption that an operator is aware of their interaction with the medical device. Another consideration is that the patient may be in contact with other devices (or Earth Ground) that an operator is not aware of.

I believe that once-upon-a-time during (60601-1) training it was pointed out that if the medical device could be set on a patient (per the use cases, a common example is something that might be used during emergency medical procedures), that the device could be then considered to be subject to the requirements around applied parts (for means of patient protection) even if it was not an applied part.

 

[MedWizard]

All of the parts you enumerated above come in contact with the OPERATOR and require means of operator protection.

Among the distinctions between an OPERATOR and a PATIENT is the concept that a patient may not be aware that the medical device is being applied to them, whereas there is a presumption that an operator is aware of their interaction with the medical device. Another consideration is that the patient may be in contact with other devices (or Earth Ground) that an operator is not aware of.

I believe that once-upon-a-time during (60601-1) training it was pointed out that if the medical device could be set on a patient (per the use cases, a common example is something that might be used during emergency medical procedures), that the device could be then considered to be subject to the requirements around applied parts (for means of patient protection) even if it was not an applied part.

I agree that electric parts should have means of OPERATOR PROTECTION, but should the listed parts also be seen as applied parts? That is at the core of my question.

I believe subclause 3.8 of 60601-1 describes what you mention in your last paragraph:

"However, a part that unintentionally comes into contact with an unconscious, anaesthetized or incapacitated PATIENT can present the same RISKS as an APPLIED PART that necessarily has to contact the PATIENT. On the other hand, a part that an active PATIENT can reach out and touch might present no more RISK to that PATIENT than it presents to an OPERATOR."

 

[Peter Selvey]

For home use equipment (and in general), it is necessary to consider the "patient" and "operator" as two people even though in reality it might actually be the same person. Operator parts could be defined as being associated with functions such as set up, control, shutdown, maintenance (these being obviously performed by a conscious person and only brief contact), while the "applied part" is associated with the actual measurement, treatment, delivery or compensation.

To give an example why this is needed, consider a home use blood pressure meter device often run off 4 x AA 1.5V batteries. At some point it will require the operator to replace the battery, exposing them to 1.5V which exceeds the limits allowed for patients. So there is a clear example of the need to separate "operator" and "patient" based on the function.

Another example is that "applied parts" can't exceed 41°C (which is just +1°C rise in 40°C ambient) without triggering clinical justification, IFU disclosures (see 11.1.2.2). Obviously that makes no sense for parts of the equipment that are only briefly contacted for the purpose of set up, shutdown or control.

Basically, you would not be able to comply with the standard without this approach. I had a quick look in IEC 60601-1-11 to see if this common sense approach is actually stated in either the normative or informative sections, but no luck. Anyone else find anything?