by Patricia Maddix
The Tandem t:slim X2 insulin pump is a device about 3 inches long, 2 ½ inches wide and 3/8 inches thick. It has a removable cartridge that holds up to 300 units of rapid-acting insulin. The cartridge connects to tubing, with a catheter on the end that goes under the skin on the body. The pump is programmed with the user’s individual insulin needs. The pump then delivers micro-doses of insulin continuously 24 hours per day. This delivery is called basal insulin, which the body needs. When the user plans to eat or needs to bring down an unexpected high blood glucose level, the grams of carbohydrate or desired dose of insulin has to be entered into the pump to deliver the insulin. This is called a bolus dose. Until recently, these bolus doses needed to be entered on the touch screen of the pump and could not be done without some sighted assistance.
Although the Tandem t:slim X2 insulin pump is not completely accessible to blind or low-vision users, it does have an app called t:connect for iOS and Android that is very accessible, except for the graph that shows blood glucose and insulin delivery history. The mobile app has been available for a couple of years to allow users to view many status features of the pump, but until this summer, users could not interact in any way with the pump directly from the app. Tandem has been rolling out the feature that allows users to program and deliver a bolus directly from the mobile app.
To be able to use the new bolus feature, the customer is first sent an e-mail with instructions and links to online training, a code that will be needed to upgrade the pump, and a link to upgrade the pump. The training modules and upgrade process require some sighted assistance. Once the upgrade is completed, the app is accessible.
The t:connect app has 4 tabs along the bottom of the screen. From left to right, they are Dashboard, Bolus, Notifications, Settings. Once the user taps on the bolus tab, a screen appears where the user can enter in either the units of insulin they want to deliver or the grams of carbohydrate they plan to eat. For low vision users, the buttons, words, and numbers are very large and high contrast. For even better contrast, the phone settings can be set to gray scale inverted. For blind users, all of the information reads aloud. When entering carbs, the program takes into account not only the carbs but the current blood glucose level from the connected Dexcom sensor as well as insulin on board and displays a recommended dose. All of the computations are itemized for the user to review. The user can then proceed to the next and confirm buttons to bring up the bolus delivery button and administer the dose with fingerprint, face ID, or passcode verification. Alternately, the user can choose to adjust the recommended dose if they feel they know something that the pump does not, like they plan to exercise right after the meal, etc.
The user can also enter the exact units of insulin they want to deliver without entering carbs to deliver a correction for a high blood glucose or if they choose to do their own calculations. The app, just like the pump, asks you several times to confirm the dose to avoid mistakes.
Prior to the release of this new mobile bolus feature, the only way a blind user could deliver a bolus without sighted assistance was to use the Quick Bolus feature directly on the pump. This feature when enabled provides audible beeps when pressing an external button to count out and confirm the dose. Using this method, the pump cannot adjust the dose based on a blood glucose above or below the pump’s pre-programed target of 110. The user would have to calculate these adjustments on their own.
Just remember, the Tandem t:slim X2 pump itself is a flat touch screen with no audible feedback to select on-screen buttons to get to menus and perform programming and site change functions. Blind users are able to manage the delivery of insulin and respond to notifications independently between site changes that generally occur every 2 to 3 days. However, the process to draw up insulin in a large syringe, remove air from the cartridge, remove bubbles from the syringe and put the insulin into the cartridge as well as priming the tubing with insulin to see when it comes out of the catheter cannot generally be done independently by blind users. This process also requires the ability to use the pump’s touch screen to go into the menu and proceed through numerous screens to complete this process.
Another tab on the app is called Dashboard, which contains a lot of useful information about the current status of the pump. It reads aloud using VoiceOver. Some of the information included is: battery charge percentage, units of insulin remaining in the cartridge, current blood glucose when connected to Dexcom G6, insulin on board, time in range for the last 24 hours, current basal rate, last bolus and whether it was one you delivered or if Control IQ (the pump’s automated bolus feature) delivered it, the time the last bolus was delivered, if Control IQ is turned on or off, which basal profile is currently running, when your sensor was started, and a few other items.
Another tab is called Notifications. The pump periodically gives alerts and notifications that show up on the touch screen of the pump. These can be viewed and read aloud in the app in this tab. They cannot be cleared or dismissed from the app, but blind users can easily learn to do this.
Tandem is to be applauded for the development of this new accessible app which allows the user to feel more confident in taking correct bolus insulin and reduces stress around the multiple doses of insulin required every day. Technology surrounding diabetes is changing very rapidly, and this is a wonderful first step toward fully accessible medical devices. We still have a long way to go and need to continue to advocate for people who are blind and have diabetes.