Software bug leads to insulin pump injuries and Spurs recall

Managing type 1 diabetes is a high-stakes balancing act: Too much or too little insulin is a bad thing, leading to blood sugar levels that fall outside a narrow range with potentially disastrous consequences. from either side. Many diabetics choose to use an insulin pump to make it all easier to manage, but as a recent insulin pump software recall by the U.S. Food and Drug Administration shows, the technology is not foolproof .

Fortunately, the recall is very limited in scope. It is intended for users of the Tandem t:slim X2 insulin pump, and specifically for the companion app running on iOS devices. The mobile application is intended to run on the user’s phone to monitor and control the pump. The pump itself is a small, rechargeable device that users often keep on their belt or tucked in a pocket that delivers a slow, steady infusion of insulin throughout the day, as well as larger bolus doses to compensate for meals .

The t:slim X2 insulin pump.

But version 2.7 of the t:connect mobile app can crash unexpectedly, and on iOS devices, this can lead to the operating system continually relaunching it. Every time it does this, the app attempts to reconnect to the pump via Bluetooth, which eventually drains the pump’s battery. Once the battery is discharged, no more insulin can be delivered, which can lead to a condition called hyperglycemia (“hyper” meaning excess, “gly” referring to sugar, and “emia” meaning presence in the blood – excess sugar in the blood).

Untreated high blood sugar can progress to a much more serious condition called diabetic ketoacidosis, which can lead to coma and death. Fortunately, no one suffered this fate from this bug, but the FDA received more than 200 reports of injuries, hence the recall. Tandem sent a notice to all affected customers in March to update their apps, but it is still possible that some users did not receive the message.

Besides the human cost of this bug, there is a lesson here about software design and unintended consequences. While it intuitively seems like a great idea to automatically restart a crashed application, especially one with a critical life safety feature, in hindsight the better solution might have been to simply go into safe mode and to alert the user with an alarm. It’s a lesson we learned while exploring space, and it seems to apply here as well.

Images: AdobeStock, Tandem Diabetes