March 2011

 

CATARACT/ IOL

 

Targeting TASS


by Vanessa Caceres EyeWorld Contributing Editor
 

 

Questionnaires, site visits reveal TASS causes

TASS 1-day post-op Source: Simon Holland, M.D.

Researchers recently gleaned a better understanding of the causes of toxic anterior segment syndrome (TASS). A report in the July 2010 issue of the Journal of Cataract & Refractive Surgery (JCRS) reported on the results from 77 questionnaires and 54 site visits, all from surgical centers that have reported cases of TASS since 2006. TASS causes a sterile inflammatory reaction and typically presents 12 hours to 2 days post-op. Limbus-to-limbus corneal edema, damage to the endothelial cell layer, a breakdown in the blood-aqueous barrier, iris damage, and glaucoma secondary to trabecular meshwork damage are all associated with TASS.

Although topical steroids can treat TASS, in severe cases, permanent corneal edema, glaucoma, and other chronic inflammation can occur.

TASS received a great deal of attention within ophthalmology in 2006 when a number of cases were reported and again when the syndrome was associated with a particular irrigating solution. "We wanted to point out that TASS still occurs," said study co-investigator Nick Mamalis, M.D., professor of ophthalmology, John A. Moran Eye Center, ophthalmology and visual sciences department, University of Utah, Salt Lake City. Dr. Mamalis is co-chair of the ASCRS TASS Task Force as well. "When there is an outbreak, people hear a lot about it. When things quiet down to baseline, people tend to forget about it. It's important to bring it to the forefront," he said.

In addition to the goal of avoiding TASS outbreaks, another reason to bring TASS to the forefront is because its causes, as shown by the study results, are due to some common errors, said Henry F. Edelhauser, Ph.D., professor of ophthalmology and director of ophthalmic research, Emory School of Medicine, Atlanta.

"Cataract surgery is to some extent routine. A lot of times, it's a high-volume surgery, and things are moving quickly," said Dr. Edelhauser, who is also co-chair of the ASCRS TASS Task Force. "It takes a lot to clean instruments, and sometimes there's not adequate time."

Study details

Study investigators, led by Carolee M. Cutler Peck, M.D., John A. Moran Eye Center, retrospectively analyzed 77 questionnaires that were completed on the ASCRS website. The goal of the questionnaires was to facilitate the reporting of TASS cases. The questionnaires addressed instrument cleaning, reprocessing practices, surgical protocols, and techniques for cleaning instruments. Ultimately, 68 questionnaires were included in the study. The centers that responded were mostly in the U.S. (n=62), although there was one center each from Argentina, Brazil, Italy, Mexico, Spain, and Romania. The reporting centers had performed 50,114 cataract surgeries and had reported 909 cases of TASS.

The study also took into account site visits to certain practices that had experienced TASS outbreaks. "From January 1, 2006, to date, the 54 centers visited by a TASS Task Force member reported 367 cases of TASS in 143,919 procedures performed; 61% of them occurred in 2006," the investigators wrote.

The number one factor associated with TASS was inadequate flushing of the phaco and irrigation/aspiration (I/A) handpieces after surgery. "Of the 68 centers that filled out questionnaires, more than 60% used less than the recommended 120 cc per port (range 2 to 100 cc per port)," investigators wrote. "Other factors included occluded I/A tips during surgery, a symptom of inadequate flushing."

Of the centers for which site visits were conducted, 48% had inadequate flushing of phaco and I/A pieces and cannulated equipment.

The study found that 43% of centers for which site visits were conducted had used enzymatic cleaners and detergents, 37% had used reusable cannulas, and 35% had inadequate or no manual cleaning of instruments; 28% had used preserved epinephrine in the anterior chamber.

"Cleaned instruments were often left on towels that were not lint-free, and many centers did not train personnel regarding TASS and proper cleaning practices," study investigators reported.

A number of other items were frequently reported at centers with TASS cases, including use of tap water with no sterile water final rinse, reuse of single-use items, and poor instrument maintenance.

The cleaning issues associated with TASS do not surprise Dr. Edelhauser. "These instruments have small holes and bores, and everything in cataract surgery swims in viscoelastic. The viscoelastic is sticky and difficult to clean out." Dr. Edelhauser knows a nurse who likens viscoelastic in instruments to a child spilling maple syrup on the kitchen tablein other words, it's not going to get cleaned off easily.

Combine the difficulty of cleaning these instruments with the hectic pace at high-volume centers, and the chance for a problem like TASS to occur increases, he said.

The study also tracked medications given intracamerally or added to a balanced salt solution that became another potential source of TASS. Twenty-five percent of centers that responded to the questionnaire reported adding antibiotic agents to the balanced salt solution irrigant; 21% had used intracameral antibiotic agents. "The use of antibiotic agents may be associated with toxicity when they are included in anterior chamber irrigant and when injected intracamerally at the end of a case," investigators wrote. Although some intracameral antibiotics have been studied as prophylaxis against infection, investigators still view their use with caution.

Preventing TASS

Based on the study results, investigators gave a number of recommendations to ophthalmic surgical centers. Here are some of them:

1. Follow instrument manufacturers' cleaning instructions to the letter, Dr. Edelhauser said. This can make a big difference in preventing TASS. As easy as that may sound, many tend to read the instructions only when they encounter problems, he explained. By following manufacturers' instructions, surgical centers can decrease infection risk and avoid problems identified due to the use of enzymatic detergents, ultrasonic baths, and other common cleaning methods.

Handpieces should be wiped off with a lint-free cloth and immediately immersed in sterile water until they are flushed, the study investigators advised. This was not done at 89% of centers visited, but by doing so you can remove residual viscoelastic and debris from drying within the handpiece and tips.

2. Keep a number of surgical trays on hand. Thorough instrument cleaning may not be possible in the middle of a busy schedule, so surgeons should make sure to have a number of instrument trays on hand during the day, Dr. Edelhauser recommended. By having an adequate number of surgical instruments available, staff will be less likely to reuse instruments that are not properly cleaned or that should not be reused, yet another common problem found at centers with TASS cases.

3. Send surgical nurses and technicians to trainings to stay up-to-date with instrument cleaning and infection control protocols, Dr. Edelhauser said. Even though surgeons may attend such sessions at meetings, they are usually not the ones cleaning the instruments, he said. In addition to meeting sessions and specific trainings, publications such as the July JCRS article or "Recommended practices for cleaning and sterilizing intraocular surgical instruments," published in the June 2007 issue of JCRS and written by ASCRS and the American Society of Ophthalmic Registered Nurses, should be required reading, Dr. Edelhauser said. Before the June 2007 publication, not much distinction was made between the cleaning of ophthalmic instruments and larger surgical instruments, such as those for abdominal surgery. "Now we can refer people to those guidelines," he said.

4. Do not use products with preservatives or additives in the anterior chamber. Considering that 52% of surgical centers had used preserved epinephrine in balanced salt solution and 37% were using other preserved medications intracamerally, investigators shared a warning about ocular toxicity that can be caused by bisulfites.

5. Report cases of TASS if you experience them, Dr. Mamalis said. "This allows us to know what's occurring and put it in our database. It's also helpful to the surgeon and surgical center because we can give them tips to help improve," he said. Although no one really knows how common TASS is, Dr. Edelhauser believes surgeons are becoming more open about reporting it. "There's a freer exchange of information now, and that's positive," he said.

Editors' note: Drs. Edelhauser and Mamalis have no financial interests related to their comments.

Contact information

Edelhauser: 404-778-5853, ophthfe@emory.edu
Mamalis: 801-581-6585, nick.mamalis@hsc.utah.edu

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