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Antibiotic prophylaxis covered in webinar

10 diciembre, 2017 0 comentarios

Antibiotic prophylaxis covered in webinar

Experts discussed considerations for antibiotic prophylaxis in cataract surgery by Ellen Stodola EyeWorld Senior Staff Writer

October 2017 issue of EyeWorld. Con permiso de EyeWorld.

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A recent webinar sponsored by the ASCRS Cataract Clinical Committee examined the topic of antibiotic prophylaxis for cataract surgery. Faculty weighed in on intracameral and topical antibiotics and factors to consider. Speakers included Richard Kent Stiverson, MD, Denver, Colorado, Neal Shorstein, MD, Walnut Creek, California, David F. Chang, MD, Los Altos, California, and Francis Mah, MD, La Jolla, California.

Dr. Mah presented on current trends in infectious endophthalmitis and touched on topical antibiotics, which he noted are the majority of what U.S. ophthalmologists are using. There is no FDA-approved antibiotic currently on the market for prophylaxis in cataract surgery, he said.

Dr. Mah then shared data on topical antibiotics and post-surgical endophthalmitis rates. “In general, we’re not doing too bad in terms of infectious endophthalmitis following cataract surgery,” he said, with the accepted rate of about 1 in 1,000. But what’s causing it? Dr. Mah said there was a landmark prospective study looking at this, which showed that 60% of patients with bacterial endophthalmitis were culture-positive.

Dr. Mah went on to discuss the prognosis for these patients. After endophthalmitis, about 43% of patients have vision of 20/40 or better but 34% have 20/200 or worse af- ter treatment. The prognosis is bad if initial vision is poor, Dr. Mah said.

We know that there are some relatively es- tablished risks for endophthalmitis. Poste- rior capsule rupture, preexisting periocular infections, and immunocompromised status are risk factors. However, Dr. Mah noted that it is multifactorial.

Prophylaxis is one area that physicians can potentially manage, Dr. Mah said, adding that the source of the organism is endog- enous. The lids, lashes, and lacrimal system harbor the organisms that cause the major- ity of endophthalmitis.

There are two approaches that require che- mo prophylaxis. One is the reduction of en- dogenous surface organisms using either antiseptic or topical antibiotic, and the other is eradication of pathogens that gain entry into the ocular tissues using an antibiotic, Dr. Mah said.

As far as eliminating endogenous surface organisms, povidone iodine is effective, he said, adding that physicians should leave povidone iodine in the eye for at least 5 min- utes of contact time. The landmark study showed significant reduction of endophthal- mitis rates with use of povidone iodine, Dr. Mah added. There was a 75–80% reduction in endophthalmitis with povidone iodine.

What do physicians know about topical an- tibiotic prophylaxis? One of the first studies was in 1964, Dr. Mah said. There were 22 infections in 20,000 cataract extractions. A later follow-up study in 36,000 consecutive retrospective operations found that switch- ing antibiotics could help. Dr. Mah said there is in vivo animal data from a study at the University of Pittsburgh that found that us- ing an agent was better than saline, and us-ing it preop and postop was bet

ter than one or the other. There are problems with topical drops, Dr. Mah noted, including com- pliance, manual dexterity, ocu- lar surface toxicity, penetration into the eye, and cost. In terms of educating patients, Dr. Mah said that a study from Canada showed that upward of 92% of patients were incorrectly putting drops in following routine cata- ract surgery.

When using topical antibiotics in the U.S., most physicians begin use about 1–3 days prior to sur- gery, with frequent dosing the day of surgery. Dr. Mah added that mostly there is no post- operative tapering, and antibi- otics are often used at least 7 days postoperatively.

In summary, he said that topical antibiotics are widespread and entrenched in the U.S., post- operative use is greater than preoperative use, retrospective studies suggest efficacy, and surrogate evidence suggests ef- ficacy. However, he noted that efficacy of topical antibiotics is unproven in a placebo-controlled prospective study.

Dr. Shorstein gave a brief histo- ry of intracamerals, referencing several studies. He discussed a study from Sweden published in the Journal of Cataract & Re- fractive Surgery (JCRS) in 2002 and a large randomized control trial by the European Society of Cataract & Refractive Surgeons (ESCRS), which was initiated in 2003 with results published in JCRS in 2007.

Dr. Shorstein discussed his personal experience at Kaiser Per-

manente. In 2007, they noticed a
slight increase in endophthalmitis.
They began to use cefuroxime in
2007 and later between 2009 and
2011 added moxifloxacin and van-
comycin. The 2007 endophthalmi-
tis rate was similar to the baseline
rate of the ESCRS study, he said,
noting that his group saw a 22-fold
decrease in endophthalmitis from
the beginning of the study to the
end. There were about 2,000 eyes
that received an intracameral in-
jection alone with no perioperative
or postoperative drops prescribed.
After this, Dr. Shorstein said a Na-
tional Eye Institute (NEI) grant
prompted further study of larger
groups in the region, which result-
ed in an in-depth look at 315,246
eyes with 250 surgeons. He noted
three take-home messages. Look-
ing at the topical alone group com-
pared to those with an added in-
tracameral injection, there was a
42% reduction in endophthalmitis
in the injection group, which was
statistically significant. Patients
who received no antibiotic (e.g.,
forgetting to fill the prescription)
had nearly a two-fold increase in
the risk of endophthalmitis com-
pared to the topical group. The
question remains whether topical
drops provide any additional ben-
efit when intracameral antibiotic is
injected. Finally, comparing intra-
cameral cefuroxime and moxiflox-
acin in those patients who were
taking topical drops in addition
to the injection, the cefuroxime
group had the highest confidence
in reduction of endophthalmitis,
Dr. Shorstein said. The moxiflox-
acin group had a slightly higher
rate, but the confidence interval
was wider. It would take tens o

thousands of patients and years of study

surgeries and had five cases of endophthal- anti-VEGF treatment, and use early

mitis.” From 2005–2016, reformation of the anterior chamber and stromal hydration of the incision were done with balanced salt solution containing vancomycin, and Dr. Stiverson said there were 55,000 cases without incidence of endophthalmitis.

Dr. Chang discussed the rare but devastat- ing complication of HORV, which he said is one of the worst complications that can happen during cataract surgery because of the potential for bilateral blindness. This was first brought to surgeons’ attention in 2015 with a paper published in Ophthal- mology. The recommendation was made to consider avoiding intracameral vanco- mycin use for routine prophylaxis. “Given the widespread use of vancomycin, many of us were concerned about drawing this conclusion from a series of just six pa- tients,” Dr. Chang said.

ASCRS and the American Society of Retina Specialists (ASRS) formed an HORV Task Force to analyze the prevalence, etiology, treatment, and outcomes of this disease. They set up an online registry, conducted an e-survey of the ASCRS membership, did a literature search, and consulted with immunologists. The paper detailing these results was published in Ophthalmology in May, Dr. Chang said. It reported a series of HORV in 36 eyes of 23 patients (13 bi- lateral and 10 unilateral), all of which re- ceived intraocular vancomycin. It could occur 1–21 days after surgery, he said, adding that if the second eye received vancomycin, the onset of HORV was often faster and more severe.

pan-retinal photocoagulation.

Dr. Chang said that HORV is most like- ly a type III delayed hypersensitivity to vancomycin. Because there is no specific test for type III hypersensi- tivity, it is difficult to prove, but every confirmed case of HORV to date re- ceived intraocular vancomycin follow- ing uncomplicated cataract surgery. In addition, systemic vancomycin causes a similar type III hypersensi- tivity called leukocytoclastic vasculitis with delayed onset and a predilection for venules. A 2014 ASCRS member survey found that 50% of respon- dents were using intracameral antibi- otic, with vancomycin being the most common agent (37% overall and 52% of American respondents).

The HORV Task Force offered several considerations, Dr. Chang said. These include weighing the risk of HORV against the risk of endophthalmitis when using vancomycin, reconsidering vancomycin with close sequential bi- lateral cataract surgery, and knowing that HORV may not cause symptoms in the first eye and a dilated retinal exam may be the only way to detect it. He said that many surgeons have switched to using intracameral cefu- roxime or moxifloxacin in light of the potential for HORV.

View the full presentation of this we- binar at learning/video/antibiotic-prophylaxis- cataract-surgery.

Dr. Chang offered recommendations for
management. He said to consider avoid-
ing intravitreal vancomycin if HORV is
suspected, consider an ocular and/or
systemic work-up for other syndromes if
there is an unclear diagnosis, use aggres-
sive systemic and topical corticosteroids,
consider intraocular steroids, use early

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