Toxic Anterior Segment Syndrome (TASS): A System's Based View of a Day in the Life of a Canula

Case Presentation:

During a routine cataract surgery, we called for a syringe filled with BSS to hydrate the wound at the end of the case. The syringe was topped with a standard reusable 27-gauge cannula that had been cleaned and sterilized according to our standard O.R. protocol. As the surgeon was about to hydrate the wound with the cannula he depressed the plunger of the syringe to remove any air bubbles and instead of clear BSS exiting the syringe, blue colored fluid came out .

Despite not having used the syringe yet in the eye, the anterior chamber was thoroughly irrigated with sterile BSS. Following otherwise uneventful surgery, the patient did well with a typical post operative course. However, this event seemed like a close call and could have very easily resulted in Toxic Anterior Segment Syndrome (TASS; described below). To help us understand the process and pitfalls involved in cleaning and quality control of our operating instruments, a chain of custody study was initiated to evaluate the sterilization process for reusable ophthalmic surgical instruments.

Investigation revealed that the same cannula had been used to inject Trypan blue dye during cataract surgery three days prior. According to protocol, the cannula, along with all of the other instruments used that day, were cleaned, sterilized, and processed for reuse in subsequent cases. However, as is evident here, something about the system was not working in order for residual Trypan blue dye to remain in a cannula that had been properly processed. Since the cleaning and processing of surgical instruments is something of which most surgeons know very little, we sought to determine what exactly is involved in a day in the life of a Troutman cannula.

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Case 85 Toxic Anterior segment Syndrome (TASS): Systems-Based



Toxic Anterior Segment Syndrome (TASS)

Toxic Anterior Segment Syndrome (TASS) is an acute, sterile anterior segment inflammation following generally uneventful cataract and anterior segment surgery.

One of the main factors in differentiating TASS from an infectious endophthalmitis is the rapid onset. Most patients with TASS will develop symptoms within 12 to 24 hours of the surgery. Common findings on anterior segment slit lamp examination include increased cell and flare with associated fibrin and possible hypopyon formation. Patients may show signs of diffuse corneal edema, and they may also show signs of iris atrophy with pupillary abnormalities and eventual increased intraocular pressure.

It is important to differentiate sterile postoperative inflammation from infectious endophthalmitis as the evaluation and treatment of these patients are markedly different. Patients with TASS will often respond quite rapidly to treatment with intense topical corticosteroids. It is important that the patients be evaluated often to ensure that the inflammation is clearing and that the patientís intraocular pressure is under control. The clearing of the inflammation and eventual patient outcome is related to the severity of the toxic insult at the time of surgery. Fortunately, most patients reported to date are in the category of a moderate toxic inflammation.

TASS may be related to problems with any irrigating solution or other solution placed in the patientís eye during surgery including Balanced Salt Solution (BSS) or anything added to the BSS. Material placed in the eye during surgery such as anesthetics, Ophthalmic Viscoelastic Devices (OVD), antibiotics, or other medications has been found to be related to TASS. Problems related to the cleaning and sterilization of instruments for cataract surgery have been found to be a common source of TASS.