Investigation of a Toxic Anterior Segment Syndrome outbreak (TASS) in British Columbia, Canada, 2017
What:
Paper Presentation | Présentation d'article
When:
4:35 PM, Saturday 2 Jun 2018
(3 minutes)
Where:
How:
Authors: Simon P. Holland, Chanut Nithithanaphat, Karrie Hammond-Collins, Marcus Lem, Douglas Walter Mock
Author Disclosure Block: S.P. Holland: Grant/research support; Name of Commercial Company(s); ALCON. Membership on an advisory panel, standing committee or board of directors; Name of Commercial Company(s); Allergan. C. Nithithanaphat: None. K. Hammond-Collins: None. M. Lem: None. D. Mock: None.
Abstract Body:
Purpose: An increase in the number of voluntarily reported TASS cases to the Canadian Ophthalmic Society (COS) TASS Task Force from a total of 14 clinics occurred between September 2016 and March 2017. In British Columbia in early 2017, a cluster of TASS cases prompted the need for an investigation to identify any common sources among the cases.
Study Design: A case-control study to identify risk factors associated with TASS was conducted by the Canadian Field Epidemiology Program (CFEP) in conjunction with the BCCDC and COS TASS Task Force.
Methods: Ten incident cases of TASS from three separate facilities were summarized using descriptive epidemiology. A chart review of 3:1 controls to cases was conducted to examine a variety of intra-operative exposures. Odds ratios for exposure variables, along with corresponding 95% confidence intervals and two-tailed Fisher Exact p-values, were calculated. Site observations of the three implicated facilities were conducted.
Results: All clinics reported at least one case in the same week with one clinic reporting all 6 cases on the same day. None of the exposures studied significantly influenced the risk of developing TASS at the 5% level of significance. These results are consistent with the small sample size. Observational epidemiology showed that endotoxins detected from an automated flushing device (QuickRinse,QR) were a possible cause for one of the three clinics. All clinics made improvements to their standard operating procedures for re-processing instruments, specifically elimination of enzymatics and detergents, following the recommendations of this investigation.
Conclusions: TASS outbreaks are often multifactorial, primarily related to issues with ophthalmic instrument re-processing. Because of the multiple steps and products involved in the re-processing of instruments, and the typically small sample sizes, TASS outbreaks are difficult to investigate. This research presents one of few case-control studies conducted during TASS outbreaks, though it did not provide evidence of a unifying etiology. Additionally, reporting of TASS cases and outbreaks is voluntary and inconsistent in Canada. The presence of endotoxins detected in a widely used automated flushing device is of concern as this device is a Level 1 healthcare product and is exempt from federal regulation. There is also concern regarding variability in the use of enzymatics and detergents which have been linked to previous outbreaks. Cataract surgery remains vulnerable to unpredictable outbreaks of TASS and the recent increases in Canada merits investigation and renewed vigilance for early detection and correction of potential risk factors.
Author Disclosure Block: S.P. Holland: Grant/research support; Name of Commercial Company(s); ALCON. Membership on an advisory panel, standing committee or board of directors; Name of Commercial Company(s); Allergan. C. Nithithanaphat: None. K. Hammond-Collins: None. M. Lem: None. D. Mock: None.
Abstract Body:
Purpose: An increase in the number of voluntarily reported TASS cases to the Canadian Ophthalmic Society (COS) TASS Task Force from a total of 14 clinics occurred between September 2016 and March 2017. In British Columbia in early 2017, a cluster of TASS cases prompted the need for an investigation to identify any common sources among the cases.
Study Design: A case-control study to identify risk factors associated with TASS was conducted by the Canadian Field Epidemiology Program (CFEP) in conjunction with the BCCDC and COS TASS Task Force.
Methods: Ten incident cases of TASS from three separate facilities were summarized using descriptive epidemiology. A chart review of 3:1 controls to cases was conducted to examine a variety of intra-operative exposures. Odds ratios for exposure variables, along with corresponding 95% confidence intervals and two-tailed Fisher Exact p-values, were calculated. Site observations of the three implicated facilities were conducted.
Results: All clinics reported at least one case in the same week with one clinic reporting all 6 cases on the same day. None of the exposures studied significantly influenced the risk of developing TASS at the 5% level of significance. These results are consistent with the small sample size. Observational epidemiology showed that endotoxins detected from an automated flushing device (QuickRinse,QR) were a possible cause for one of the three clinics. All clinics made improvements to their standard operating procedures for re-processing instruments, specifically elimination of enzymatics and detergents, following the recommendations of this investigation.
Conclusions: TASS outbreaks are often multifactorial, primarily related to issues with ophthalmic instrument re-processing. Because of the multiple steps and products involved in the re-processing of instruments, and the typically small sample sizes, TASS outbreaks are difficult to investigate. This research presents one of few case-control studies conducted during TASS outbreaks, though it did not provide evidence of a unifying etiology. Additionally, reporting of TASS cases and outbreaks is voluntary and inconsistent in Canada. The presence of endotoxins detected in a widely used automated flushing device is of concern as this device is a Level 1 healthcare product and is exempt from federal regulation. There is also concern regarding variability in the use of enzymatics and detergents which have been linked to previous outbreaks. Cataract surgery remains vulnerable to unpredictable outbreaks of TASS and the recent increases in Canada merits investigation and renewed vigilance for early detection and correction of potential risk factors.
