A new spectrophotometric method to detect residual amounts of peroxide after reprocessing hemodialysis filters.

Moacir De Oliveira,Bento Fortunato Cardoso Santos,Maria Claudia Cruz Andreoli,Silvia Regina Manfredi,Nadia Karina Guimarães,Miguel Cendoroglo Neto,Ana Cristina Carvalho Matos,Ilson Jorge Iizuka,Marcelo Costa Batista,Maria Aparecida Dalboni

doi:10.1590/s1679-45082011gs1945

Moacir De Oliveira, Bento Fortunato Cardoso Santos + Show 8 more

Open Access

https://doi.org/10.1590/s1679-45082011gs1945

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Abstract

Reuse of hemodialysis filters is a standard practice and the sterilizing chemical most often employed is peracetic acid. Before starting the dialysis session, filters and lines are checked for residual levels of peracetic acid by means of a non-quantitative colorimetric test that is visually interpreted. The objective of this study was to investigate a new quantitative spectrophotometric test for detection of peracetic acid residues. Peracetic acid solutions were prepared in concentrations ranging from 0.01 to 10 ppm. A reagent (potassium-titanium oxide + sulfuric acid) was added to each sample in proportions varying from 0.08 to 2.00 drops/mL of solution. Optical densities were determined in a spectrophotometer using a 405-nm filter and subjected to visual qualitative test by different observers. A relation between peroxide concentrations and respective optical densities was observed and it was linear with R2 > 0.90 for all reagent/substrate proportions. The peak optical densities were obtained with the reagent/substrate ratio of 0.33 drops/mL, which was later standardized for all further experiments. Both qualitative and quantitative tests yielded a specificity of 100%. The quantitative test was more sensitive than the qualitative test and resulted in higher positive and negative predictive values. There was a difference between observers in the qualitative test and some samples with significant amounts of peroxide were not detected. A quantitative spectrophotometric test may improve detection of residues of peracetic acid when compared to the standard visual qualitative test. This innovation may contribute to the development of safer standards for reuse of hemodialysis filters.

Highlights

Hemodialysis (HD) is a relatively safe procedure but several complications may occur due to side effects related to normal extracorporeal circuit, technical errors, or to abnormal reactions of patients to the procedure[1,2].From inception, maintenance HD therapy has been a challenge because of its many bioincompatible components
For concentrations of 0.1 and 0.5 ppm, Optical densities (OD) increased as the R/S rose from 0.08 drops/mL to 0.33 drops/mL, and decreased with higher R/S (0.5 to 2 drops/mL)
In this study it was found that the quantitative test could increase patient’s safety in the reuse process of HD filters after performing quantitative test with the visual colorimetric test and calculating the positive and negative predictive values, sensitivity and specificity

Summary

Introduction

Hemodialysis (HD) is a relatively safe procedure but several complications may occur due to side effects related to normal extracorporeal circuit, technical errors, or to abnormal reactions of patients to the procedure[1,2].From inception, maintenance HD therapy has been a challenge because of its many bioincompatible components. Reuse of HD filters is a common practice in Brazil and in the United States[5]. Major advantages of this practice include cost reduction and a decrease in the incidence of first use syndrome[6,7,8,9]. Major disadvantages include exposure of the internal milieu to germicides, risk of pyrogenic reactions and infections, reduced efficiency of the dialyzers, and possibly increased oxidative stress[8,9,10,11,12,13,14]. In Brazil, similar rules are enforced by the National Health Surveillance Agency (ANVISA), which is the regulatory agency[16]

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