Interoperability of pumps and components

Interoperability means the ability of two devices to exchange data and commands between them, safely and without errors. An interoperable pump receives insulin delivery commands from an external device and sends back information about its own status. The communication is wireless, following technical rules set in advance [1].

The basic idea is that you can build a system out of separate parts, from different manufacturers, instead of a closed package with all the components from the same manufacturer. The pump, the sensor and the algorithm are treated as distinct products, each with its own role. Each part can come from a different manufacturer, provided it has been verified for that combination and carries the interoperability designation [2].

An interoperable pump is a pump built specifically to accept commands from outside safely. It delivers the doses requested by an algorithm running on another device, for example a phone app. The pump confirms every command it receives. The first pump of this kind was approved in 2019, in a category created specially for it, that of interoperable pumps [3]. This category carries a technical name in the American regulations, that of a pump which accepts an external controller (ACE pump).

This technical name does not exist as such in Europe, where the generic term interoperable pump is used [1]. Such a pump must remain safe even when the connection is lost. If it no longer receives commands, it returns to the basal rates programmed in advance and alerts you [4]. The pump also keeps a log of the commands received, of the alarms and of the connections established with various other devices.

Yes, but only if that pair has been tested and approved. Automated systems frequently use a pump from one company and a sensor from another. The combination is not, however, completely free officially. The manufacturer establishes exactly which devices its product can work with [5].

The list of accepted combinations is found in the instructions for use and on the manufacturer's website. This list changes over time, as new devices and new approvals appear [6]. Check the list before you change a component, and always consult your medical team about what you would like to do.

You can choose separately, but not from an unlimited list. In fact you choose from a small number of combinations that have already been verified: a certain pump, with a certain sensor and with a certain algorithm [7]. Within these combinations you have real freedom [6].

The choice is limited by the fact that the three parts have to understand each other every few minutes, without error. This requires very thorough testing for every possible combination. The available combinations also differ from one country to another [8].

An interoperable algorithm is the program that decides how much insulin you receive, approved as a stand-alone product. The algorithm receives the values sent by the sensor and commands the doses to the pump, without being tied to a single device model it can run on [1]. The first approval of this kind was also granted in 2019 [9].

The algorithm can sit in the body of a tubed pump, in a patch pump or in a phone app [10]. Being a separate product, it can be improved through direct updates, without you having to change the devices it runs on. The algorithm nevertheless remains limited to working only with integrated sensors and with interoperable pumps from the approved categories [1].

No. Interoperability opens up the possibility of a connection, but it does not guarantee it. Every pair made up of a pump and a sensor has to be verified and declared separately by the manufacturer. In the case of sensors, the capacity for interoperability is conveyed by the designation integrated [11]. An integrated sensor has proven enough accuracy and precision to be able to enter an interoperable system [12] [13]. Accuracy and precision are different things. In other words, an interoperable sensor is what we call an integrated sensor.

The reason why the possibilities of combining various devices are limited has to do with safety. A wrongly interpreted signal would lead to a wrong dose of insulin. That is why the precision, the transmission speed and the behavior of the system when some data are missing are tested thoroughly [14]. Without this verification, the combination remains unapproved, even though the devices could technically connect to each other and all carry the interoperable designation, or the integrated designation in the case of sensors.

You check in three places:

• The instruction manual — in the chapter on compatibility;
• The list published by the manufacturer — it is updated quite often [6];
• The list of accepted phones and operating system versions — it matters if you use a phone app [15].

A simple phone update can block a combination that worked perfectly until then. Ask your medical team before you make any important change to your system [2].

No, if the new sensor appears on the compatibility list of your pump. The system carries on working without problems once you pair the two devices [16]. Sometimes a software update on the pump or in the app is also needed, in order to include a newer approved type of sensor [17].

The answer becomes yes if the new sensor has not yet been expressly approved for your pump. The connection cannot be forced, even though the two devices seem close in technology [11]. In this case you can choose between waiting for the approval and changing the pump or the algorithm, depending on which one limits your access to the new sensor.

Yes, and this is the main practical gain of the modular design. A software update can bring new functions to the same pump, including a better algorithm. The device stays the same, only the program inside it changes [18].

Updates also come with certain conditions. As a rule they apply only to devices still under warranty and only after you go through a short training [8]. After every update, check that your settings have remained unchanged.

You gain the freedom to choose. You can keep the pump you have got used to and move to a new sensor, or the other way round. You receive new improvements through updates, without waiting for the replacement with a completely new device [10].

This freedom also has a cost. Technical support comes from several companies, and when something breaks down it is not always clear whom to call. Sometimes only the complete package is reimbursed, not the parts chosen separately [4] [8].