A deadly type of surgical error – accidentally leaving sponges inside patients – could be eliminated by waving a special type of wand over the patient’s wound, according to researchers.
They have invented special medical sponges containing radio frequency identification (RFID) chips – a technology currently used to find lost pets and track food items in stores. Doctors will be less likely to accidentally leave these sponges inside surgery patients, suggests their new study.
Previous studies have suggested that doctors make this mistake in about one in every 10,000 surgeries in the US. And in the year 2000 alone, experts estimated that nearly 60 US patients died as result of this error.
There are widely-publicised cases in which surgeons stitch up patients after unwittingly leaving metal instruments, such as scissors, inside them. But in reality, about 80% of the objects accidentally left inside patients are sponges.
These sponges, which can sometimes be as small as a green pea, are crucial for soaking up blood during surgery, allowing doctors to better see the area on which they are operating. They can also provide extra grip for instruments being used on slippery organs.
When left behind accidentally in the body, however, the surgical sponges can obstruct intestines or may lead to sepsis (toxicity) as they can harbour deadly, toxin-producing bacteria.
To keep this from happening, medical procedures require that doctors count sponges at least three times per procedure: at the beginning and end of the operation and also once they have stitched up the incision. But doctors operating under emergency conditions may not have time to perform all these counts, says the research team led by Alex Macario of the Stanford University Medical Center in California, US.
The team tested sponges containing RFID tags which were about the size of a small coin. The small coil inside the chip uses applied magnetic energy to transmit data to a wand-shaped scanning device. Each chip cost only about $0.25.
Eight patients undergoing abdominal surgery, such as a kidney transplant, agreed to participate in the trial. One surgeon placed either a tagged or untagged sponge while the other surgeon looked away. The edges of the incision were held closed as the second surgeon waved the wand over the area.
A total of 28 RFID tagged sponges were tested over the course of the experiment. The eight doctors using the wand detected all of the tagged sponges correctly, without any mistakes, within an average of 3 seconds. The device did not erroneously detect any of the regular, untagged, sponges.
"It turned out the technical part of the device worked 100% of the time," says Macario, whose co-authors hold patents related to RFID-tagged sponges.
But he adds that the approach is "still prone to human error" and notes that surgeons may wave the wand too far away from the closed incision or forget to use it altogether. Macario also says that the RFID tags used in the study have a malfunctioning rate of less than 3 per million and that more tests are needed to know how well tagged sponges work.