SDC goes Real-Time

For real-time communication in dynamically interconnected medical device theatres

Surgical devices which emit energy, such as HF electrosurgical units or power systems, pose particular challenges regarding the timing and reliability of control data. Delays during energy transfer or switch-off are unacceptable. The timing requirements are defined by the standards governing the application in question, but also by the complexity of the application. They must be adhered to in all circumstances, including when the network is at full capacity. 

During the wireless triggering of e.g. an HF electrosurgical unit, the time delay of the transmission path must also be taken into account. In addition, other application cases also require real-time communication, such as closed-loop control or waveform synchronisation.

The use case shows how the steute universal foot switch controls different surgical devices in accordance with the current standards and customer requirements. Critical functions, such as speed control or triggering of the HF electrosurgical unit, are performed with RT-SDC. 

Less critical functions, such as zoom or video camera control, are performed with standard SDC. Pedals can be assigned to the various functions via a portable web-based GUI. Of course, assignment is governed by different rules. For example, the motor can only be controlled using the left analogous pedal, or coagulation only assigned to the blue pedal.

The RT-SDC functionality is to be viewed as a real-time extension to the SDC family of standards. Standard functions, such as Discovery, device descriptions (MDIB), exchange of parameters and the controlling of less critical functions, occur via SDC. 

Critical functions, such as speed control or the triggering of an HF electrosurgical unit are managed by RT-SDC. Other constituent parts of RT-SDC are the querying and setting of parameters, as well as eventing. Performance when triggering operations via SDC depends on the particular device, and times are also strongly dependent on the network load. With RT-SDC, performance is better, also depending on the device, but independent of the network load.