Safety of non-return valves in infusion systems in radiology : integrative review

Objective: to analyze, from the literature, the scientific production related to the safety of non-return valves in radiology. Method: an integrative review (IR). The terms used during the search were classified by PubMed, Web of Science and SCOPUS, performed from March 2017 to March 2019. Results: the sample consisted of 139 articles, of which 7 were from PubMed; 7 (LILACS), 1 (CINAHL), 33 (Web of Science) and 91 (SCOPUS). In addition, the reference analysis of selected texts and related articles was performed. In this IR, only 5 (3.6%) studies were selected and evaluated, pointing out a scarce world scientific production in this area. Conclusion: the safety of non-return valves usage in infusion system in radiology is not a consensus yet and depends on various physical, chemical and microbiological aspects. Descriptors: Contamination; Infection; Microbiology; Radiology; Vascular access devices. RESUMO Objetivo: analisar, a partir da literatura, a produção científica relacionada à segurança de válvulas antirrefluxo em radiologia. Metodo: uma revisão integrativa (RI). Os termos utilizados durante a busca foram classificados pelo PubMed, Web of Science e SCOPUS, realizada de março de 2017 a março de 2019. Resultados: a amostra foi composta por 139 artigos, dos quais 7 eram do PubMed; 7 (LILACS), 1 (CINAHL), 33 (Web of Science) e 91 (SCOPUS). Além disso, foi realizada a análise da referência de textos selecionados e artigos relacionados. Nessa RI, apenas 5 (3,6%) estudos foram selecionados e avaliados, apontando uma escassa produção científica mundial nessa área. Conclusão: a segurança do uso de válvulas antirrefluxo no sistema de infusão em radiologia ainda não é um consenso e depende de vários aspectos físicos, químicos e microbiológicos. Descritores: Contaminação; Infecção; Microbiologia; Radiologia; Dispositivos de acesso vascular. RESUMÉN Objetivo: analizar, a partir de la literatura, la producción científica relacionada con la seguridad de las válvulas antirreflujo en radiología. Método: una revisión integradora (RI). Los términos utilizados durante la búsqueda se clasificaron mediante PubMed, Web of Science y SCOPUS, que se realizó entre marzo de 2017 y marzo de 2019. Resultados: la muestra se compuso de 139 artículos, 7 de los cuales eran de PubMed; 7 (LILACS), 1 (CINAHL), 33 (Web of Science) y 91 (SCOPUS). Además, se realizó análisis de referencia de textos elegidos y artículos relacionados. En esta RI, solo se seleccionaron y evaluaron 5 estudios (3,6%), señalando una escasa producción científica global en esta área. Conclusión: la seguridad del uso de válvulas antirreflujo en el sistema de infusión radiológica aún no es un acuerdo general y depende de muchos aspectos físicos, químicos y microbiológicos. Descriptores: Contaminación; Infección; Microbiología; Radiología; Dispositivos de acceso vascular. How to cite: Azevedo MPF, Jesus NM, Monteiro RM, Razaboni AM, Andrade D, Watanabe E. Safety of non-return valves in infusion systems in radiology: integrative review. Rev Pre Infec e Saúde [Internet].2019;5:8600. Available from: http://www.ojs.ufpi.br/index.php/nupcis/article/view/8600 DOI: https://doi.org/10.26694/repis.v5i0.8600 Review


INTRODUCTION
Non-return valves (NRVs) usage is fundamentally important for energy generation in nuclear power plants and hydraulic systems. Although its usage has begun in other areas, it was in health that a great increase was noticed in the last decade, so much so that they came to be present in surgeries with propofol, in vesical catheters and patients with urinary tract infection. [1][2][3][4][5][6] For use in health field, such valves are designed, but not all are evaluated, before they are commercialized. Through contrast injectors, their main purpose is to prevent backflow of blood, [7][8]     To evaluate in vitro integrity and bacterial contamination in connectors with NRVs. In total, 200 latex NRV samples were used in this study, 40 from each brand (Braun Melsungen ® , Braun Spezial ® , Infudrop ® , Becton-Dickinson ® , Smith-Medical ® ). An infusion system connected to a syringe pump with water was simulated, in continuous backflow. Infusion rates of the pump were of 0.1 and 1mL/h for integrity experiments for up to 20min. In bacterial contamination experiment, Staphylococcus aureus (ATCC25923), Staphylococcus epidermidis (ATCC35984) and Proteus mirabilis (ATCC35659) are used at two rates (0.1 and 1mL/h) for 2h. Subsequently, bacterial contamination was investigated in the infusion system, in a backflow at 2mL/h for 72h, with 1% propofol drip (Disoprivan ® , AstraZeneca GmbH, Wedel, Germany) or physiological solution (B. Braun, Melsungen, Germany).
NRVs did not reliably prevent fluid backflow and do not work as a filter for microorganisms.
E2-Preliminar y report: biosafety analysis of one-way backflow valves for multiple patient use of low osmolar intravenou s contrast solution.
To determine in vitro integrity of NRVs in preventing multi-use contamination of intravenous contrast in radiology. Three Medex Inc. ® (Hilliard, Ohio, USA) NRVs with spring every 10 batches (n=30) and three springless Merit Medical System ® (Salt Lake City, Utah, USA) NRVs from two batches (n=6) were used for the experiments: structural, functional and biological. Besides, a single springless Namic ® (Namic Contrast Saving Delivery System, Glenn Falls, New York, USA) NRV was used for the structural experiment. For the NRV structural / functional experiment, a pressure of 60psi was exerted in backflow for 15s (short period) and 60min (long period) with the aid of a syringe pump. Furthermore, a contrast injector (Liebel-Flarsheim Company, Cincinnati, Ohio, USA) was used to simulate clinical practice in an experiment with radionucleotide and a biological one. In In the structural experiment, the opening pressures of Medex Inc. ® NRVs (with spring) were of 3.4±0.9psi (mean and standard deviation), while pressures of Merit Medical System ® and Namic ® NRVs (springless) were less than 0.1psi. One (10%) of 10 Medex Inc. ® NRVs showed a change in the pressure profile during the short-period return with 15psi. On the other hand, there was no change in the pressure profile in NRVs with 60psi for 60min. The other NRV brands showed changes in profile pressures in short period (Merit Medical System ® ) and long period (Namic ®  To determine in vitro bacterial load contamination from "patient model" connected to IV tubing. An infusion pump (Infusomat ® fmS, B. Braun, Melsungen, Germany) was connected and powered for 5h to a "patient model" with bacterial (10 6 CFU/mL) and viral inocula from Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and bacteriophage T3 from E. coli B14, IV tubing (two connectors with four NRVs) and two 50mL syringes (B. Braun, Melsungen, Germany). One of syringes was filled with 1% propofol (Disoprivan ® , Astrazeneca GmbH, Wedel, Germany), and the other with physiological solution. In total, 55 microbiological experiments (bacteria and bacteriophage) were performed from the "patient model" and from three different parts of the IV tubing and the two syringes. Before and after 5h, the "patient model" showed increased microbial load of 67 times (P. mirabilis), 10 times (S. aureus), 3 to 6 times (S. epidermidis, E. coli, P. aeruginosa) and 10 to 333 times (bacteriophage T3).
Even with increased microbial load (bacteria and bacteriophages) in the "patient model", no contamination was presented from three different parts of the IV tubing and the two syringes.
Experimental data suggest that the design with multiple NRVs (four) in paired configuration prevents IV tubing contamination, during five hours of anesthesia with propofol.

E4
-Microbial Safety Assessmen t of a Double Check-Valve Patient To investigate Secufill ® safety of multiple uses of contrast injectors, under worst-case clinical conditions. This study was performed in three stages. In the first one, 100 Secufill ® samples (connector with two NRVs) were evaluated in vitro (four batches and two manufacturing processes) for the opening and closing time (use of contrast and physiological solution) with two ADDIX (Medex) and Dual Shot Alpha (Nemoto Kyorindo Co., Ltd.) contrast injectors used for magnetic resonance imaging According to the first stage, the worst NRV closure condition was with the use of contrast. In addition, there was no difference between batches, manufacturing processes and injectors. In the second stage, the increase of the contact time of Patent Blue V ® with NRVs was directly proportional to dye diffusion through Secufill ® . Moreover, backflow was more evident using contrast medium and a 45- To evaluate in vivo the risk of cross-contamination, in multiple uses of contrast injectors, from a new infusion system with NRVs. To simulate clinical conditions, a contrast injector (Dual Shot GX, Nemoto Kyorindo, Tokyo, Japan) coupled to two disposable syringes (100 and 200mL), T-connector and injection set to Transflux ® (P & R, Diepenbeek, Belgium) -(connector with two NRVs) as well as connector without NRV. In total, 12 Transflux ® systems were evaluated according to Protocol A: multiple uses of disposable syringes with physiological solution (n=6); and Protocol B: multiple uses of disposable syringes with physiologic solution and contrast (n=6). The experiments were carried out on two New Zealand rabbits (Animal House, KU Leuven, Belgium) inoculated with radiotracer. 10min after the completion of protocols A and B, Transflux ® were, carefully, disconnected from the rabbits and replaced with new ones. The radioactivity readings of the two rabbits and 12 Transflux ® were obtained every minute.
In protocols A and B, the detection of radioactivity was higher in the rabbit bloodstream than in the connector without NRV (p<0.0001). In fact, there was no radioactivity detection in Transflux ® as well as in the injection set (p=0.003).
Transflux ® were suitable and safe, that is, they prevented the cross-contamination risk in multiple uses of automatic contrast injection system.

DISCUSSION
There is no consensus on the reliability of non- The devices employed to simulate blood and contrast injector pressures were: syringe pump, [12][13] infusion pump, 7 contrast injector, [13][14]8 at 60psi for 15s (short period) and 60min (long period) in backflow, 13  This research has limitations. The national and international scientific literature is very scarce in relation to the safety of NRVs usage in infusion system in radiology.

CONCLUSION
In conclusion, the safety of non-return valves usage in infusion system in radiology is not a consensus yet and depends on various physical, chemical and microbiological aspects. Besides, well-designed experimental studies with methodological rigor are needed to address gaps on the safety of non-return valves and to help in making the proper decision in clinical practice.

COLLABORATIONS
MPFA, RMM and EW: contribution in the collection, analysis and interpretation of the data; contributed in critical review and writing of the manuscript. AMR and DA: contributed in critical review and writing of the manuscript. All authors agree and are responsible for the contents of this version of the manuscript to be published.

ACKNOWLEDGMENTS
Does not apply.

CONFLICTS OF INTEREST
There are no conflicts of interest to declare.

AVAILABILITY OF DATA
Available upon request to the authors.

FUDING SOURCE
Does not apply.