Objective: Surgical instrument oversupply drives cost, confusion, and workload in the operating room (OR). With an estimated 78-87% of instruments being unused, many health systems have recognized the need for supply refinement. By manually recording instrument use and tasking surgeons to review instrument trays, previous quality improvement initiatives have achieved an average 52% reduction in supply. While demonstrating the degree of instrument oversupply, previous methods for identifying required instruments are qualitative, expensive, lack scalability and sustainability, and are prone to human error. In this work, we aim to develop and evaluate an automated system for measuring surgical instrument use.

Materials and Methods: We present the first system to our knowledge that automates the collection of real-time instrument use data with radio-frequency identification (RFID). Over 15 breast surgeries, ten carpometacarpal (CMC) arthroplasties, and four craniotomies, instrument use was tracked by both a trained observer manually recording instrument use and the RFID system.

Results: The average Cohen’s Kappa agreement between the system and the observer was 0.81 (near perfect agreement), and the system enabled a supply reduction of 50.8% in breast and orthopedic surgery. Over 10 monitored breast surgeries and one CMC arthroplasty with reduced trays, no eliminated instruments were requested, and both trays continue to be used as the supplied standard. Setup time in breast surgery decreased from 23 minutes to 17 minutes with the reduced supply.

Conclusion: The RFID system presented herein achieves a novel data stream that enables accurate instrument supply optimization.

Data from the RFID system was recorded, cropped to remove reads recorded before and after the reported start and end time of the surgery, and written to a .csv. Chronological RFID logs for each surgical specialty are in respective folders. The first column is EPC, which is the unique identifier of the RFID tag. The .csv entitled 'Decoder' links EPC numbers to instrument names for all instruments that were tagged. The second column is time. Note that in some RFID logs, there are EPCs that are not present in the Decoder. This is because other RFID tags were present in the operating room. Ethnography logs are the observers lists of used instruments. These lists are inclusive, so if an instrument is not in a list, it was not recorded as used in that surgery. Times next to each instrument correspond to the onset of use of the instrument. For some logs, many unique onsets of use were able to be recorded; for others, none were recorded. Two observers simultaneously recorded use in two surgeries. In one surgery their observations were congruent; in the other, they differed. Differing ethnography logs for equivalent case are denoted with the ethnographer's last name appended to the .csv name.

RFID log times recorded during the breast surgical oncology pilot experienced drift until a clock synchronization was performed before surgery 16. The relative times are correct, but the offset for absolute time is uncertain. RFID clock drift did not occur in orthopedic surgery or neurosurgery.