Modifying sterilization may help in TASS

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Las Vegas-Existing sterilization techniques, particularly those used in higher-volume, rapid-turnover operating rooms, may need to be modified to avoid and control future outbreaks of toxic anterior segment syndrome (TASS), Simon P. Holland, MD, FRCSC, said at the annual meeting of the American Academy of Ophthalmology here.

Reusable cannulated instruments should be avoided when possible, except for phaco tips if well-cleaned, he added, and sufficient time should be allotted to prepare and sterilize instruments between cases.

Dr. Holland, clinical professor of ophthalmology and visual sciences, University of British Columbia, Vancouver, reported the experience of a large, multi-surgeon cataract surgery clinic at which a prolonged outbreak occurred over a period of 2 years. The potential cause was endotoxin contamination of balanced salt solution (BSS).

TASS was defined as anterior segment inflammation, a fibrin and cellular response absent of vitritis usually occurring within 1 week of surgery (usually on the first day), and culture-negative intraocular biopsy results. The study included a control group of 4,800 patients who did not develop TASS despite undergoing surgery on the same day as patients who did develop it. The primary outcome measure was outbreak resolution.

Multiple interventions

Multiple interventions produced varying results, he said.

Microbiological review was obtained. Autoclave reservoirs were cultured and showed heavy contamination with endotoxin-forming gram-negative bacteria including "the usual culprits, predominantly Sphingomonas, Burkholderia, and Acinetobacter," Dr. Holland said.

Over 24 months, several changes were made at the clinic, he said.

"This is what makes teasing out the relevant data so difficult," he added.

Cleaning protocols were improved during the first month after TASS was seen. In months three to seven, no cases of TASS were diagnosed.

In month seven, a short-cycle sterilizer (Statim 5000, SciCan Inc.) was introduced and the clinic switched to bimanual phacoemulsification. Six cases of TASS followed in 2 days.

Subsequently, Dr. Holland said, "there was more intense sterilizer reservoir cleaning, the reusable tubing was discontinued, single-use phaco tips were used, the gloves were changed, filtration was added, and enzymatic cleaners" were used.

In month 13, more intense sterilizer reservoir cleaning was introduced. The filters were changed again, and wrapped cycles were used.