Tablet usage as interface

[ChetanMatad]

We have a medical device which has BLE as one of interface , We are looking at display as ipad / android tablets . Does it mean the tablet should also be 60601 standard , also if we go for 60601 standard tablet we see thicker devices instead of slim tablet available .

What limits the size reduction of the medical grade tablets . Is there a way to overcome the thickness

Regards
Chetan

 

[mr9000]

I assume the increased requirements of 60601-1 regarding electrical protection (insulation, creepage distances,...) and mechanical protection (hand-held devices must withstand a fall from 1 m) lead to a bigger diameter. I wouldn't trust a standard tablet if it slips out of my hand to still work.

 

[Peter Selvey]

In general a tablet is not a medical device and does not need to comply with IEC 60601-1, even if used as an interface.

It's the regulatory equivalent of a pen and paper pad used by a doctor to record medical information. The point is not how the item or object actually gets used (which can be medical or in the medical environment) but what the original manufacturer of the object intended it to be used for. A typical tablet manufacturer makes the table for general purpose. Installing medical software in the tablet does not make the tablet a medical device.

However, the software is a medical device. Also risk management and design controls still need to consider possible issues related to installation, compatibility, data loss, data protection, functional safety (e.g. if used to control dangerous equipment), and other issues that could arise from using a general purpose tablet in a medical environment.

That said, it is increasingly a popular option and nothing fundamentally wrong in concept.

 

[Tidge]

If the SaMD is intended to be used on a commercially available tablet, and the tablet itself is NOT on the market of a medical device, my limited imagination makes me want to consider elements of 60601-1 even if it is not appropriate to apply 60601-1.

Frankly, I am less concerned with the drop test (I am only thinking in terms of essential Performance of the SaMD), I'm more concerned about the possibility of handling (or resting on a patient) a tablet that is connected to a wall charger. Generally: I expect that most modern designs (i.e. battery, charging circuit) would not allow for a discharge through a user/patient to earth... yet I would still insist that the risk management file for the software considers this as a potential circumstance of a use scenario. The SaMD manufacturer can't really do anything about this except warn users, unless particular models of tablets are specified.

 

[Peter Selvey]

Practically there is no significant risk from electric shock. The special leakage current limits/tests in IEC 60601-1 are intended for higher risk situations such as patient contact with electrodes, invasive devices, catheters, connections with the blood circuit and so on. Normal contact with a tablet, even if a patient does not warrant these special requirements. Standards still exist for other devices and chargers and they have reasonable leakage current limits/tests for this kind of user contact. An exception might be if the patient had some kind of invasive contact with exposed parts, but I doubt this would be the case.

 

[kevinkre]

Our device connects via USB to the mobile/tablet, and it was not an issue for UL. However, the 5V charger was an issue. (UL gave two choices: go with a medical grade 5V charger, or disable the ECG recording when charger was connected). We are updating our design to remove the battery to utilize the 5V power from the mobile/tablet. As per Peter's comment, I don't think this will be an issue either as we have Two MOPs with transformer isolation from patient to mobile/operator. Audits mainly concentrated on our SAMD (App). Because we use the USB connector on the mobile/tablet it cannot be connected to a wall charger while in use, which simplifies things. Thanks Peter.

 

[Tidge]

Because we use the USB connector on the mobile/tablet it cannot be connected to a wall charger while in use, which simplifies things. Thanks Peter.

There exist cables which allow for power to be connected while a USB (data connection) is maintained. This is a common configuration for "USB-on-the-go" setups... for example, connecting a cell phone to a USB drive while accessing content. Even external (micro)SD card readers drain the batteries of phones, larger drives may require more power which is why these cables exist to avoid the phone discharging during use.

I'm not calling for a redesign of the system, and it isn't clear this would need to happen in your configuration, just that it isn't impossible to provide charging to the tablet while the USB connector is in use.

 

[kevinkre]

Our prior device is a host and provides charging for the mobile, so I get it. Our device takes < 100mA, BTW. As far as an intervening setup that would introduce another path of potential electrical hazard via the USB, this is risk reduced (and cautioned against in our IFU and would amount to customer misuse). The elimination of the Li Ion battery is a major risk reduction compared to the small risk of customer misuse by introducing other components in the USB path. Thanks Tidge for giving me the opportunity to speak more on our design.