Patient Safety Tip of the Week
October 28, 2014
RF Systems for Retained Surgical Items
In our multiple prior columns (see list at the end of today’s
column) on retained surgical items (RSI’s) we’ve talked about the various human
factors that come into play and some potential technological solutions. The manual
surgical count is helpful at identifying potential retained items but is a
system prone to errors. Using radiographs to detect retained surgical items can
be costly and also prone to error. So just about everyone agrees that
technological solutions are needed.
Two logical technologies showing promise are those used in
grocery stores or in organizations where inventory may be mobile and in need of
tracking. We, of course, are referring to barcode technologies and radiofrequency
technologies. In the barcoding system, a scanner reads a barcode from each
sponge as it is introduced to the sterile field and then again as it is removed
and disposed of. This primarily helps with the counting process (it cannot
locate sponges or other items that are still inside the patient). The
radiofrequency (RF) technologies detect sponges with an RF chip sewn in (with
the newer ones having chips with unique identification codes sewn in). These
have the advantage that scanning with a “wand” or a “mat” can help locate
missing items, even those still inside the patient. Also, in our November 5, 2013 Patient Safety Tip of the
Week “Joint
Commission Sentinel Event Alert: Unintended Retained Foreign Objects” we
discussed that a group applying engineering
problem-solving methodology to address the issue (Anderson
and Watts 2013) concluded that the only way to eliminate the dangers is to alter
the sponge itself! Hence their solution was to pursue development of a bioresorbable surgical sponge.
But while we’re waiting for those bioresorbable
sponges we need to look at the existing technologies. A new study (Williams
2014) reports a greater reduction of rates of retained surgical sponges at
hospitals using RF technology compared to those not using it. Williams and
colleagues analyzed data from a large university consortium database that had
information on incorrect counts and retained surgical items. They found that five organizations that
implemented RF technology collectively demonstrated a 93% reduction in the rate
of reported retained surgical sponges, compared to a 77% reduction at 5 comparable
organizations that do not use RF technology.
They also showed
that average OR time over a 2-year period was, on average, 16 minutes shorter
in hospitals that had implemented RF technology.
They went on to do a cost analysis and estimate the cost
savings (based on costs of intraoperative x-rays and extra OR time involved)
and costs avoided (projected medical costs and litigation costs). They
estimated that using RF technology to prevent retained surgical sponges could
result in almost $600,000 savings annually compared to the cost of the RF
technology at $191,000.
So their conclusion is that RF technology was effective at
reducing retained surgical sponges and was very cost-effective.
But how robust are those conclusions? There may be certain
biases and methodological flaws that lead to questioning those conclusions.
The rate of reported retained surgical sponges in the
pre-intervention period was higher at the 5 organizations that implemented RF
technology. They, thus, had an opportunity to demonstrate a greater percent
improvement even if they simply “regressed to the mean”. The authors do not note
why the 5 organizations that implemented RF technology did so. Was it because
they had higher rates of RSS’s to start with?
The authors do state that their analysis “demonstrates that
heightened national efforts aimed at preventing RSI’s have had a positive
effect on reducing the number of retained sponges”. Yet in another section because
of more quarter-to-quarter variability in the RSS rates at those hospitals not
using RF technology they state “this variability indicates the results will not
likely be sustained”.
The disparity in OR time between users and non-users of RF
technology cannot be conclusively attributed to the RF technology since they
did not have such OR time data prior to the implementation and did not case mix
adjust. However, they cited work we’ve previously discussed by Greenberg et al.
(Greenberg
2008) that showed the average time to resolve count discrepancies is 13
minutes and an unpublished study that showed a time reduction of 23 minutes. So
that the 16 minute difference in the Williams study might be attributable to
the RF technology is very feasible.
Also, cost savings analyses such as these, even when “conservative”,
probably overestimate actual savings. For example, the statistic “one minute of
OR time costs $62” came from the literature and may not be applicable to your
OR. That number was likely based on hospital charges rather than costs. So if
you have to take an extra 16 minutes to reconcile a count and you pay your
staff a salary and don’t have to pay overtime and you don’t have another case
ready to fill that 16 minutes, your actual costs are very low (you pay for
continued anesthesia and your anesthesiologist might bill for another “unit”).
And the cost of getting an x-ray is not $286 since your x-ray technician is
likely salaried and the incremental cost (variable cost) of an x-ray is really
only a few dollars at most. So be wary when you see an analysis that suggests
you’re going to have a net benefit of over $400,000!
But there are other excellent contributions from the study
by Williams and colleagues. They did both an aggregate analysis of either
surgical count issues or RSI events in their database and a more detailed
review of narrative descriptions in a subset of records within that database. Interestingly,
the most commonly retained surgical items were instrument fragments (eg. drill bits, broken or missing pieces of instruments),
accounting for 58% of RSI’s. Sponges were the second most frequent retained
surgical item, with sponges and towels accounting for 32% of RSI’s. Note that
needles were the items most frequently involved in incorrect counts but not in
cases of actual retained items (presumably because most of these were picked up
by radiographs done before the wound was closed).
The most common issue they identified was that the surgeon continued to close despite noting
the counts were incorrect. Subsequent imaging studies led to identification
of the RSI in those cases, leading to reopening the patient either before or
after the patient left the OR.
Factors contributing to the events were similar to those in
the literature, including emergency procedures, trauma cases, unplanned changes
in procedure, multiple procedures, staffing changes
during cases, lengthy procedures, communication failures, and failure to follow
protocols. They also noted use of large numbers of sponges as a contributing
factor. In addition, sponges that were cut or sponges that were left in a
bucket or room from a prior case contributed in some cases, as did “inappropriate”
use of sponges for laboratory specimen handling or dressings.
Note that a recent
meta-analysis of studies on factors contributing to RSI’s (Moffatt-Bruce
2014) demonstrated that seven risk factors are significantly associated
with increased RSI risk:
- intraoperative blood loss
>500 mL (odds ratio [OR] 1.6)
- duration of operation (OR
1.7)
- more than 1 subprocedure (OR 2.1)
- lack of surgical counts
(OR 2.5)
- more than 1 surgical team
(OR 3.0)
- unexpected intraoperative
factors (OR 3.4)
- incorrect surgical count
(OR 6.1)
Interestingly, changes in nursing staff, emergency surgery,
body-mass index, and operation "afterhours" were not significantly
associated with increased RSI risk. The researchers proposed a risk
stratification system based on these variables.
The problem of retained surgical items has persisted. We
strongly back investigation of technological solutions to the problem. But we
need to be very careful that we do not let biases and other methodological
flaws lead us to premature conclusions about any of the technological
solutions. Unfortunately, we don’t 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 RSI’s.
Our prior columns on retained surgical items/retained
foreign objects (RSI’s/RFO’s):
- June 12, 2012 “Lessons
Learned from the CDPH: Retained Foreign Bodies”
- November 2012 “More
on Retained Surgical Items”
- January 8, 2013 “More
Lessons Learned on Retained Surgical Items”
- November 5, 2013 “Joint
Commission Sentinel Event Alert: Unintended Retained Foreign Objects”
- August 19, 2014 “Some
More Lessons Learned on Retained Surgical Items”
References:
Anderson DE, Watts BV. Application of an Engineering
Problem-Solving Methodology to Address Persistent Problems in Patient Safety: A
Case Study on Retained Surgical Sponges After Surgery.
Journal of Patient Safety 2013; 9(3): 134–139
Williams TL, Tung DK, Steelman VM,
et al. Retained Surgical Sponges: Findings from Incident Reports and a
Cost-Benefit Analysis of Radiofrequency Technology. Journal of the American
College of Surgeons 2014; 219(3): 354-364
http://www.journalacs.org/article/S1072-7515%2814%2900384-6/pdf
Greenberg CC, Regenbogen SE, Lipsitz SR, et al. The Frequency and Significance of
Discrepancies in the Surgical Count. Ann Surg 2008;
248(2): 337-341
Moffatt-Bruce SD, Cook CH, Steinberg SM, Stawicki
SP. Risk factors for retained surgical items: a meta-analysis and proposed risk
stratification system. J Surg Res 2014; 190(2):
429-36
http://www.journalofsurgicalresearch.com/article/S0022-4804%2813%2901427-3/abstract
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