TASS outbreaks trending down

June 1, 2013

Findings point to improvements in cleaning procedures, less reuse of cannulas

Take-Home Message

Outbreaks of toxic anterior segment syndrome are decreasing, but more attention to adequate cleaning of equipment is needed.

 

By Lynda Charters; Reviewed by Nick Mamalis, MD

Salt Lake City-Generally, the number of toxic anterior segment syndrome (TASS) outbreaks is trending in a downward direction, according to the updated findings of the TASS Task Force.

Positive steps included a reduction in inadequate handpiece flushing volumes and increased use of distilled/deionized final rinses, whereas increased use of enzymatic detergents and ultrasonic baths were identified as negative trends associated with development of TASS.

The syndrome is characterized by a constellation of symptoms that often manifests within 12 to 48 hours after cataract or any anterior segment surgery. Clinical findings include diffuse corneal edema that extends limbus to limbus, widespread endothelial damage, acute postoperative anterior segment inflammation, fibrin, and hypopyon.

The updated findings gleaned from surveys received from surgical sites at which TASS developed were presented by Nick Mamalis, MD, professor of ophthalmology at the John A. Moran Eye Center, University of Utah, Salt Lake City.

The surveys, which were collected between June 1, 2007, and March 1, 2012, addressed cleaning and instrument processing and medications and products used in the perioperative period. The investigators offered recommendations to the responding sites and conducted site visits when requested. The information gained from those visits was analyzed as well. The results obtained from June 1, 2009, to March 1, 2012, were compared with the previously reported results to identify trends.

Dr. Mamalis reported that 130 questionnaires were submitted and analyzed. Seventy-one site visits were conducted, and 1,570 cases of TASS developed in about 69,000 cataract surgeries performed at the reporting centers worldwide.

Data analysis indicated that instrument processing was the factor most commonly associated with development of TASS. This included inadequate flushing of phacoemulsification and irrigation/aspiration handpieces, use of enzymatic cleaners, detergents, poor instrument maintenance and processing, and reuse of single-use products. Antibiotics in balanced saline solution (BSS), preserved epinephrine, inappropriate agents used for skin prepping, and powdered gloves were identified as culprits in the development of TASS.

Important trends

When the data from the early and late periods were compared, a few trends were identified. There was a 26% decrease in inadequate handpiece flushing volumes, a 27% increase in the use of deionized/distilled final rinses, and reduction in the use of reusable cannulas. In addition, antibiotics added to BSS are being used less often.

An interesting development was that in 2010 and 2011, several U.S. manufacturers of epinephrine stopped producing the preservative/stabilizer-free drug.

“We expected an increase in TASS cases because of this, but did not observe one,” Dr. Mamalis said. “In fact, at sites visited, the use of preservative-containing epinephrine dropped significantly.”

He also noted that at sites visited, the use of enzymatic detergents dropped by 36%. This may be due to the fact that many of the sites visited had already submitted surveys and were experiencing recurrent cases of TASS.

“The use of enzymatic detergents is a primary issue we address when sites are first contacted,” he explained.

In summary, the positive trends identified were that more sites reported adequate handpiece flushing volumes, fewer sites use reusable cannulas, there is increased use of distilled/deionized final rinse, more sites process ophthalmic instruments separately from other instruments, antibiotics are added to BSS less frequently, and there is decreased use of preserved intracameral anesthetics.

Real concerns are the increased use of enzymatic detergents and ultrasonic baths, Dr. Mamalis noted.

However, the good news is that the number of TASS outbreaks reported is trending downward; no spike in outbreaks has been associated with discontinuation of several brands of preservative- and stabilizer-free epinephrine.

“Awareness of these findings and the recommended best practices will enable surgical centers to update their practices as needed to minimize the risk of TASS,” Dr. Mamalis concluded.

Nick Mamalis, MD

E: nick.mamalis@hsc.utah.edu

Dr. Mamalis has no financial interest in the subject matter. This article was adapted from Dr. Mamalis’ presentation during the annual meeting of the American Society of Cataract and Refractive Surgery.