In our June 12, 2012 Patient Safety Tip of the Week ďLessons Learned from the CDPH: Retained Foreign BodiesĒ we noted that existing guidelines all stress that the count is not the only important thing. We noted that the count may be correct in 88% of cases of retained surgical items (RSIís). A recent update by the Pennsylvania Patient Safety Authority (Martindell 2012) also noted that only 22.8% of the RSIís reported to them in 2011 had an incorrect count.
Therefore, it remains critical that the surgeon perform a thorough methodical wound exam in each and every case. Itís also the reason for the ongoing search for technological solutions that might better help prevent retained surgical items.
One of the problems in looking at any interventions or technological solutions is how to measure the impact of such in preventing RSIís. Given the relative rarity of RSIís, a randomized controlled trial (RCT) using the absolute number of RSIís as a primary endpoint would require a huge population to demonstrate statistical significance. Such is not likely to be performed. More likely studies will need to look at surrogate measures such as detection rates in cases of discrepant sponge counts
Using X-rays to detect potential RSIís has been used. Using them in all cases would likely be too costly and time consuming. However, many hospitals do use them selectively, requiring them in all high-risk cases (i.e. those cases with many of the risk factors we mentioned in our June 12, 2012 Patient Safety Tip of the Week ďLessons Learned from the CDPH: Retained Foreign BodiesĒ). But even X-rays are not infallible. Some of the items retained may not be radiopaque. In some cases X-rays may fail to include sufficient exposure or coverage and can miss some RSIís. A recent case presentation in CMAJ (Grant-Orser 2012) demonstrated an instance where conventional X-ray failed to identify a retained sponge but CT scan did. They go as far as to say that in cases where a discrepant count has occurred and a diaphragm-to-pubis plain radiograph fails to show an RSI, further imaging with CT should be considered.
Atul Gawande, who had done some of the seminal work documenting risk factors for RSIís, and colleagues (Greenberg 2008) did perform an RCT of a system of barcoding surgical sponges. Sponge count discrepancies were detected approximately twice as often using the barcoded technology. The barcoded system did help with things like alerting staff that a sponge had already been accounted for so that it would not get double counted. However, the amount of time required to reconcile discrepant counts and the likelihood of needing an X-ray were unchanged. Some relatively minor technological issues did arise in that study and the total time spent counting sponges was higher in the barcoded arm. Staff satisfaction with the barcoded system was mixed but overall positive. The authors concluded that the barcoded system has the potential to meaningfully reduce the risk of retained sponges but cautioned that the effects on workflow and potential introduction of some new technology related problems must be taken into consideration.
And just within the last month a couple new studies were published assessing the usefulness of radiofrequency detection systems to help prevent retained sponges. One was a prospective trial involving almost 2300 patients undergoing a variety of surgical procedures (Rupp 2012). Though they had no RSIís during the study, the radiofrequency system did assist in the resolution of one near-miss not detected by manual counting and it assisted in the resolution of 35 sponge miscounts.
The other study (Steelman 2012) compared a standard radiofrequency detection system with a new radiofrequency ďmatĒ. In a conventional RF detection system an RF chip is embedded in the fabric of the sponges and a wand is passed over the patient, triggering an alarm if a sponge with a chip is detected. The process is somewhat dependent upon good technique by the person passing the wand. The other system involves using a special RF mat that is placed beneath the patient on the operating table. When you want to see if there is a retained sponge in the patient you push a button and the mat does the scanning. The concept is that it takes away the potential human variability in scanning. They studied both systems in 203 patients, of whom 55 (27%) were morbidly obese (BMI greater than 50). They placed tagged sponges on top of the patients, one sponge over each abdominal quadrant. Overall, the RF mat detected 98.1% of the sponges. The only sponges not detected were in morbidly obese patients (i.e. the mat detected 100% of sponges in patients with BMIís less than 50). Of morbidly obese patients, the mat still detected 96.9% of sponges. There were no false positives. Then, in a subset of patients, they repeated the testing using the hand-held wand and found the sponges in 100% of cases. Thus the RF wand system outperformed the RF mat system, even in the very obese patients. The study also confirmed that a variety of objects on patients, like jewelry and adornments, did not cause false positive detections.
Keep in mind that these systems do not detect all potential RSIís. While the barcoding and RFID systems could track and identify those items that have an appropriate barcode or RFID chip, such as sponges, they would not detect things like needles and broken pieces of equipment or tools. Whole tools could be either barcoded or radiofrequency labeled. However, the issues of how durable such would be when these tools must undergo repeated sterilization procedures remain unanswered.
The CMAJ paper (Grant-Orser 2012) has a table listing the published sensitivities of the various detection methods. They note the sensitivity of manual counting is 62-88%, selective radiographic screening 85.8%, universal radiographic screening 95.5%, CT scanning 61%, barcoded sponges 97.5%, and radiofrequency-tagged sponges 100%. Note that those sensitivities were all obtained in different scenarios so they may not actually be apples-to-apples comparisons. They reinforce some of the issues we mentioned above such as increased time involved, introduction of new technological issues, etc.
The bottom line: we donít yet know what the best technological solution is to the retained surgical item problem. None is yet perfect and each has its own set of problems. So for the time being you are stuck with well-done manual counts and perhaps using one of the other technologies as an adjunct. But you can certainly expect refinements to these technologies going forward that may improve our ability to better prevent RSIís.
Our prior columns on retained surgical items/retained foreign objects (RSIís/RFOís):
Martindell D. Update on the Prevention of Retained Surgical Items. Pa Patient Saf Advis 2012; 9(3): 106-110
Greenberg CC, Diaz-Flores R, Lipsitz SR, et al. Bar-coding Surgical Sponges to Improve Safety: A Randomized Controlled Trial. Annals of Surgery 2008; 247(4): 612-616, April 2008
Grant-Orser A, Davies P, Singh SS. Cases: The lost sponge: patient safety in the operating room. CMAJ 2012; 184: 1275-1278 August 7, 2012
Rupp CC, Kagarise MJ, Nelson SM, et al. Effectiveness of a Radiofrequency Detection System as an Adjunct to Manual Counting Protocols for Tracking Surgical Sponges: A Prospective Trial of 2,285 Patients. J Am Coll Surg 2012; 215: 524-533
Steelman VM, Alasagheirin MH. Assessment of Radiofrequency Device Sensitivity for the Detection of Retained Surgical Sponges in Patients With Morbid Obesity. Arch Surg. 2012; 147(10): 955-960
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(7): 659-662
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