RFID tags help alert surgeons to problems
Author recommends use of multiple counts
Physicians at Stanford University School of Medicine in Palo Alto, CA, who tested sponges embedded with radio frequency identification (RFID) tags said the system accurately alerted surgeons when they deliberately left a sponge inside a temporarily closed surgical site and waved a detector wand over it.
Still, the lead author of the article detailing this research1 says that both technological assistance and good old reliable techniques such as counting instruments and sponges before and after an operation are necessary for optimal patient safety.
"Despite precautions such as using radio-opaque tags [which can be detected by an X-ray] and labor-intensive counting procedures, an estimated 1,500 objects are left inside patients after surgery each year in the United States; this is one out of every 10,000 surgeries that involve an open cavity," notes Alex Macario, MD, MBA, associate professor of anesthesia, department of anesthesia, Stanford University School of Medicine. "The risk of retention of a foreign body after surgery significantly increases in emergencies, with unplanned changes in procedure, and with higher body-mass index [overweight patients]."
Two-thirds of all objects left in the body cavity are sponges, notes Macario. "Retained sponges may be asymptomatic and remain undiscovered for decades," he says. "Alternatively, retained sponges may lead to infection, intestinal obstruction, and even death."
But, notes Macario, technology is only as good as its utilization in the OR by personnel — thus the need to retain standard counting procedures. "Despite the engineering success, the possibility of human error and retained sponges remains because handheld scanning can be performed incorrectly," he explains.
Testing the technology
In the study, eight untagged sponges and 28 RFID sponges, manufactured by ClearCount Medical Solutions in Pittsburgh, were placed in patients just before surgery. (The tags use a circuit that emits an identifying signal when prompted by a radio signal.
Such tags are used commercially for a variety of applications ranging from luggage tracking and preventing currency from being counterfeited to shoplift loss protection and automated highway toll collection.)
The edges of the wounds were pulled together. The researchers defined successful detection as detection of an RFID sponge within one minute.
The handheld wand scanning device successfully detected all sponges correctly — on the average, in less than three seconds.
Despite the impressive results, the chips were not perfect, says Macario. For one thing, he notes, the RFID tag is not small enough for some surgeries. "The tag used in the study is only the size of a nickel, which is fine for most surgical supplies," he says. "It can be as small as a grain of salt, but the detector needs to be right on top of it to detect it."
Further development and study is ongoing, supported by a Small Business Innovation Research Program grant and the National Institutes of Health. "The SBIR grant is to ClearCount, and they subcontract out to Stanford for this study with me as the principal investigator," says Macario.
But there's an even greater challenge, he continues. "The real challenge is how you incorporate a new device into the workflow of the operating room," he explains. "We need a system that is really fail-safe — where, regardless of how people use a counting system technology, the patient doesn't leave the operating room with a retained foreign body."
A 'fail-safe' system
Such a system, says Macario, would incorporate the type of policy currently employed at Stanford Hospital and many others for gauze sponges. It includes doing an initial count prior to surgical incision, then a second count at the beginning of wound closure, and a third and final count before the skin is closed, to reconcile with the baseline count. "Regardless of count outcomes, an X-ray is mandatory prior to leaving the OR on high-risk cases, such as surgeries lasting more than 10 hours, or trauma/emergent cases where there is no time to have adequate baseline counts," says Macario.
"Reconciling multiple such counts in a hectic OR environment leads to errors," he continues. "Counts are not used for inventory or billing purposes. The sole objective of surgical counts is to prevent a retained foreign body."
However, Macario notes, the use of such preventive measures is not universal "and a majority of retained sponges occur with normal counts, perhaps falling outside human safeguards designed to prevent these types of errors." In fact, he adds, "A retrospective review of malpractice claims related to retained foreign bodies found that sponge counts had been falsely correct in 76% of non-vaginal surgeries."
That's why Macario is convinced the future must include a combination of RFID tags and other techniques, such as counting instruments and sponges before and after an operation.
Reference
- Macario A, Morris D, Morris S. Initial Clinical Evaluation of a Handheld Device for Detecting Retained Surgical Gauze Sponges Using Radiofrequency Identification Technology. Arch Surg. 2006;141:659-662.
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