Designing a test set-up to measure electrosurgical parameters

Abstract

Safe surgical and anesthetic care is not available to 5 billion people worldwide. Many problems that are encountered when providing surgical care are related to surgical equipment. A lot of surgical equipment is designed for the use in High-Income Countries (HICs) and not specifically for Low-and-Middle Income countries (LMICs). One appliance, used in every operation room worldwide, is an electrosurgical unit (ESU). Electrosurgery is the use of a high-frequency (HF) alternating current (AC) to raise tissue temperature, making it possible to cut and coagulate this tissue. There is a large variety of ESUs available to HICs, but these do not meet the requirements for safe and proper use in LMICs. The Biomedical Engineering department at the TU Delft is currently working on a project to create an ESU for LMICs. This thesis aims to compose a list of requirements for this ESU, design a protocol and test set-up to measure electrosurgical parameters and perform an experiment to measure these electrosurgical parameters.
During the development of the list of requirements, there was a lack in the knowledge about the thermal effects of electrosurgery was found. In order to be able to fill this gap, a testing set-up was created as well as a protocol to perform measurements on electrosurgical units. Throughout the process of designing this set-up different obstacles were found which had to be overcome. These obstacles consisted of the influence of light on thermal camera measurements, the influence of a smoke extractor on thermal measurements in general, measuring simultaneously or separately with a thermal camera and a thermocouple and measuring inside the tofu or on top of the tofu with the thermocouples. Experiments provided data which concluded that light had an effect on the measurements, using the FLIR E75 camera. Therefore these experiments should be performed in the dark. Furthermore, it was found that a smoke extractor affected the surface temperature during measurements, so the smoke extractor should not be used. Other external influences did not seem to influence the measurements drastically.
Taking these factors into account, a testing set-up and protocol are created. This set-up is used to perform experiments comparing two ESUs and comparing different power settings of the ESUs. The result of these experiments show that for the Valleylab Force Fx, higher powers created higher temperatures (starting at
60 Watts). For the ERBE ICC 300, there is no significant difference in maximum temperatures per power settings. There is a large difference between the maximum temperatures of the Valleylab and the ERBE. This is probably because the Valleylab uses a power controlled system and the ERBE uses a voltage controlled system.
In conclusion, the set-up and prototype were validated and can be used to measure electrosurgical
parameters. This information can guide us in making further decisions in the design requirements for the new ESU.