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ENDOSCOPE STERILIZATION:
THE
STORY BEHIND THE BACTERIAL OUTBREAK
THAT KILLED TWO PREEMIES
IN LOS ANGELES
By Michael
D. Shaw, Contributing Columnist - HealthNewsDigest.com
Dec 25, 2006, 07:00
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Reproduced
with permission of  |
If
you're familiar with this tragic case that occurred a few weeks
ago in an LA neonatal unit, you may have also heard that the infection
was traced back to an "improperly
sterilized laryngoscope," according to the Associated Press story.
And, in the words of Dr. Laurene Mascola, director of Los Angeles
County's acute communicable disease control unit, "It's a done
deal. We have the smoking gun."
Sorry, Dr. Mascola, but what we have here is anything BUT a done deal.
 The bug that killed the two babies was Pseudomonas aeruginosa,
a bacterium infamous for its ability to thrive in numerous environments, its
tendency to cause disease in immunocompromised individuals, and its resistance
to antibiotics. P. aeruginosa produces
toxic proteins that can destroy tissue and interfere with the immune system,
and is said to be responsible for 10 percent of the 2 million hospital-acquired
infections that happen each year. Of the 2 million infections, nearly 100,000
are fatal.
As to the "improperly sterilized laryngoscope," possibly, the hospital officials
quoted in the AP story were not being precise in their terminology.
"Sterilization" is
any process whereby all forms of microbial life (bacteria,
spores, fungi, and viruses) are completely destroyed.
In practice, though, laryngoscopes are usually not sterilized, since AORN (Association
of Perioperative Registered Nurses) guidelines recommend high-level disinfection
of the laryngoscope blades, and, incredibly, recommend low-level disinfection
for the laryngoscope handle.
"High-level disinfection" is expected to destroy
all microorganisms, with the exception of high numbers of bacterial spores. "Low-level
disinfection" can kill most bacteria, some viruses, but it cannot
be relied on to kill resistant microorganisms such as tubercle
bacilli or bacterial spores.
Since laryngoscopes are
considered to be "semicritical" devices (in accordance
with the so-called Spaulding classification scheme—as the device touches
mucous membranes), high-level disinfection is indicated. Note that low-level
disinfection is recommended for "noncritical" items—the items that would
only touch intact skin.
However, as any undergraduate microbiology student will tell you, once a surface
that started off at a higher level of disinfection is touched by a surface that
is at a lower level—such as a laryngoscope blade touching a laryngoscope
handle—the higher level surface has been compromised. Indeed, this would
be a fundamental violation of aseptic technique.
Thus, you might well ask, why in the world would the guidelines provide for such
sloppy technique? In two words: Cost savings.
Laryngoscopes typically come as one handle with several blades. While there would
be sufficient inventory to allow for the more time-consuming process of high-level
disinfection for the blades, there might not be enough handles in stock to allow
this. The result is a compromised instrument, and this, alone, could explain
the LA tragedy.
Widely published infection control guru Dr. Lawrence F. Muscarella has objected
to this practice, and has cited numerous literature references proving that contamination
can occur. Check out his comprehensive website [http://www.myendosite.com].
Given that Pseudomonas aeruginosa has been
identified as the culprit, it is important to consider one other possible scenario.
Although this bug can live in many places, it does exceptionally well in moist
environments, is found in tap water, and was said to be observed in the sinks
at the very hospital involved in the deaths. Indeed, P. aeruginosa is
often observed growing in distilled water.
This is significant since AORN's guidelines have also endorsed the clinical use
of wet endoscopes and laryngoscopes. But, Muscarella states that:
"It
would be difficult to identify another 'recommended' medical
practice that poses as significant a risk of nosocomial
[hospital-acquired] infection from, for example, waterborne
bacteria (including Pseudomonas
aeruginosa) as the introduction of wet endoscopes into patients'
organs and cavities."
He adds that:
"No data or studies have been published that
support the claim that 'sterile' rinse water can be produced by filtering
a hospital’s tap water through a water filtration assembly that includes
a 0.2 micron bacterial filter." [This comment is in reference
to a particular well-known and ubiquitous reprocessing device.]
Muscarella maintains that the risk of transmission of bacteria during scope procedures
can be virtually eliminated by drying the endoscope after completion of every
reprocessing cycle. While this practice is not supported by AORN, it is recommended
by the Society of Gastroenterology Nurses and Associates (SGNA) and the American
College of Chest Physicians.
Finally, Muscarella believes that AORN's guidelines have lowered the levels of
diligence, vigilance, compliance, and concern regarding the potential for disease
transmission associated with improper reprocessing of endoscopes (including laryngoscopes).
The guidelines seem to be disproportionately influenced by cost factors and the
peculiarities of certain manufacturers' reprocessing equipment, rather than patient
safety.
It's high time that patients, their loved ones, and the physicians who treat
them demand better infection control procedures in hospitals, and that includes
tightening up guidelines such as those mentioned in this article. Only then,
will we have a "done deal."
shaw@healthnewsdigest.com
Michael D. Shaw
Exec VP
Interscan Corporation
mds1@gasdetection.com
http://www.gasdetection.com
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