Instrument Tracking in the Operating Room

Abstract

In hospitals, the duration of surgical procedures vary even when the same procedure is performed.
Surgical end-time of the procedure is currently predicted using historical data about similar procedures,
the procedure time and sometimes an indication of the operating surgeon is also taken into account.
After the start of the procedure, there is no documented communication between the operating room
(OR) planner and the surgical team inside the OR. When the procedure is finished, a nurse has to call to
inform that the next patient can be prepared for surgery. If an update of the progress of the procedure
is needed, there has to be communication between the staff outside the OR and the surgical team inside
the OR. To lower the workload and reduce the distractions for the surgical staff, the communication
needs to be automated. This can be done by developing a support system that communicates the
progress of the procedure in the OR automatically to the staff outside the OR without the need for
human interaction.
In this study, automatically communicating the progress of the procedure is realized by introducing a
radio frequency identification (RFID) system that tracks the instruments during the procedure. With
this information, the different phases of the procedure can be recognized and this will aid in the
communication and the prediction of the surgical end-time. To be able to detect the instruments with
an RFID system, a minimal reading distance is required. In this study, different approaches are tested
to increase the maximal reading distance of RFID ’on-metal’ tags to ensure the range is far enough
for the technique to be used during a totally extraperitoneal (TEP) procedure in the OR. The desired
reading distance is 50 cm. The study started with a set of instruments with RFID tags attached to them.
In a pilot study, the reading distances were measured and resulted in an average reading distance from
the antenna which was too low. Using a larger antenna resulted in a slightly higher average reading
distance, but still not high enough. Raising the power of the antenna could be increasing the reading
distance. The tests are, however, already performed with the maximally allowed 2 W.
To determine the problem with the reading distance, the different properties of the attachment of the
RFID tag to the instruments are investigated. The influences of the different properties are tested and
the results are combined to make a final design that is supposed to have a higher maximal reading
distance than the instruments in the pilot study. The final design is tested both in the clinical lab at the
TU Delft and in an operating room at the Reinier de Graaf hospital in Voorburg. The reading distances
of the tags on the final design were improved and sufficient for the use in a TEP procedure. Finally, the
tags are attached to three instruments with a temporary connection to measure the reading distances
with the influences of the instruments. The results of this test show that the desired reading distances
can be accomplished with RFID technology.