The impact of the final rinse on the cytoxicity of critical products submitted for processing* * Extracted from the thesis “Avaliação in vitro da citotoxicidade de instrumentos cirúrgicos enxaguados com diferentes qualidades de água”, Escola de Enfermagem, Universidade São Paulo, 2014.

Rafael Queiroz de Souza Cláudia Regina Gonçalves Tamiko Ichikawa Ikeda Áurea Silveira Cruz Kazuko Uchikawa Graziano About the authors



To assess the cytotoxicity of products subsequent to a cleaning process based on a validated standard operating procedure (SOP), and a final rinse with different types of water: tap, deionized, distilled, treated by reverse osmosis and ultra-purified.


This was an experimental and laboratory study. The sample consisted of 130 hydrodissection cannulas, 26 per experimental group, characterized according to type of water used in the final rinse. The samples were submitted to internal and external contamination challenge with a solution containing 20% defibrinated sheep blood and 80% of sodium chloride 0.9%. Next, the lumens were filled with a ophthalmic viscosurgical device, remaining exposed for 50 minutes, and then were processed according to the validated SOP. Cytotoxicity was assessed using neutral red uptake assay.


No cytoxicity was detected in the sample extracts.


The samples did not display signs of cytotoxicity, regardless of final rinse quality. The results obtained were reached by using only a validated cleaning operating procedure, based on the scientific literature, and on official recommendations and related regulation.

Surgical Instruments; Disinfection; Water Quality; Nursing

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