Development of a system to detect surgical material retained in the patients during operation

The retained materials during surgical procedures lead to serious complications for the patients all over the world, and can even cause death. Nowadays, even though various methods and commercial products have been developed in order to prevent surgical teams from unintentionally leaving materials inside patients, a satisfactory success level could not be achieved. The main aim of this study is to design, realize, and test a system based on radio-frequency (RF) communication that can detect surgical materials retained in the patients under surgery. In this study, two different microprocessor controlled systems that use commercially available receiver/transmitter modules operating at 433.92 and 868 MHz RF signals were developed. The transmitters, which we referred to as tags, were placed in the tanks that modeled human abdomen. The tanks were filled with water having different volumes and conductivities. The tests were performed in an environment similar to the operating rooms. In addition, in these tests the power levels obtained at the receiver with respect to the distance to the transmitter were investigated. For 433.92 MHz tags, the power levels at the receiver decreased 5-10 dBm when they were placed in the water compared to the measurements taken in the open air. In addition, tag-specific coding was realized, thus it was possible to detect which tags were active. The results showed that 433.92 MHz tags performed better than 868 MHz tags. Finally, these tests demonstrated the proof of concept of this system in detecting surgical materials retained in the patients under surgery.