Strategies for the Control of Visible Particles in Sterile Devices

2021 ◽  
Vol 64 (1) ◽  
pp. 1-17
Author(s):  
Dilip Ashtekar

Abstract Currently, limited guidance is available for the contamination control of visible particles for the manufacture of sterile devices; thus, a comprehensive guidance is warranted. Sterile devices require stringent control of visible particulates to ensure proper functionality, performance assurance of sterility, reliability, patient safety, efficacy, and product quality. This paper outlines practical and science-based strategies to prevent/minimize visible particle contamination from non-process related extrinsic and process related intrinsic sources. Witness plates are proposed as a comprehensive strategy for the real time detection of visible particles, sources of extrinsic and intrinsic visible particles, and methods to identify particle types. Implementing the control measures described herein, which include air ionization units for the control and neutralization of static charges, would maximize device yield and quality, thus reducing rework and leading to increased profitability. Installing validated air ionization systems at appropriate manufacturing and processing locations, storage, product transfer areas, and gown-up rooms can significantly reduce visible particle contamination accumulation, dispersion, and yield losses. Implementing effective material transfer practices can further minimize the risk of introduction of unwanted particles and particle dispersion within classified areas. Also described are additional control measures, such as material systems and supply chain controls, good facility design, gowning practices, manufacturing equipment and tool controls, and manual visual inspections which would further contribute to the overall reduction of particle burden. Crucial elements of an effective particle removal process are the dry and wet cleaning processes and the facility surveillance program. Process-product-particle traceability matrices can serve as effective tools to promptly identify trends and reduce device conformity defects. For this paper, the meaning of the term particle only includes particulates and particulate matter. Microbial contamination control approaches, including facility decontamination, are outside the scope of this paper.

2009 ◽  
Vol 7 (48) ◽  
pp. 1105-1118 ◽  
Author(s):  
Chun Chen ◽  
Bin Zhao ◽  
Weilin Cui ◽  
Lei Dong ◽  
Na An ◽  
...  

Dental healthcare workers (DHCWs) are at high risk of occupational exposure to droplets and aerosol particles emitted from patients' mouths during treatment. We evaluated the effectiveness of an air cleaner in reducing droplet and aerosol contamination by positioning the device in four different locations in an actual dental clinic. We applied computational fluid dynamics (CFD) methods to solve the governing equations of airflow, energy and dispersion of different-sized airborne droplets/aerosol particles. In a dental clinic, we measured the supply air velocity and temperature of the ventilation system, the airflow rate and the particle removal efficiency of the air cleaner to determine the boundary conditions for the CFD simulations. Our results indicate that use of an air cleaner in a dental clinic may be an effective method for reducing DHCWs' exposure to airborne droplets and aerosol particles. Further, we found that the probability of droplet/aerosol particle removal and the direction of airflow from the cleaner are both important control measures for droplet and aerosol contamination in a dental clinic. Thus, the distance between the air cleaner and droplet/aerosol particle source as well as the relative location of the air cleaner to both the source and the DHCW are important considerations for reducing DHCWs' exposure to droplets/aerosol particles emitted from the patient's mouth during treatments.


2015 ◽  
Vol 4 (2) ◽  
pp. 304 ◽  
Author(s):  
Bill Chiu ◽  
Shih-Cheng Hu ◽  
Angus Shiue ◽  
Yu-Yun Shiue ◽  
Zhe-Yu Huang

The trend toward narrower line width in semiconductor manufacturing has made contamination control more and more important. The presence of moisture in wafer containers, such as front opening unified pods (FOUP), can lead to the native oxide residues growth, metal corrosion, and thin film cracking on wafer surfaces. Accordingly, decreasing contamination methods and improving factory efficiency are continuously researched. Single or multi-layer particulate shields on top of wafers in FOUPs may be used to prevent pollutant accumulation. In addition, point-of-use (POU) filtration may also been used to control particle contamination in FOUPs during wafer transformation and storage. The demand for stricter filtration led to the usage of 0.10 and 0.20 µm membranes to control the contamination. However, with the introduction of finer membranes end users may have concerns about deleterious remainders on wafers from undergoing filtration. There are a total of 25 pieces of wafers in the FOUP and the arrangement is from the bottom (wafer No. 1) to the top (wafer No. 25) with arising manner. Purging FOUPs to expel moisture vapors with Clean Dry Air (CDA) is one of the most popular methods.There was no previous research for investigating the purge performance on new-generation 450mm FOUPs. This research aims to study main factors influencing the performance of the purge system on 450mm FOUPs, including moisture concentration, CDA flow rate, and filter pressure.


2018 ◽  
Author(s):  
Kankoé Sallah ◽  
Roch Giorgi ◽  
El Hadj Ba ◽  
Martine Piarroux ◽  
Renaud Piarroux ◽  
...  

AbstractBackgroundIn central Senegal malaria incidences have declined in recent years in response to scaling-up of control measures, but now remains stable, making elimination improbable. Additional control measures are needed to reduce transmission.MethodsBy using a meta-population mathematical model, we evaluated chemotherapy interventions targeting stable malaria hotspots, using a differential equation framework and incorporating human mobility, and fitted to weekly malaria incidences from 45 villages, over 5 years. Three simulated approaches for selecting intervention targets were compared: a) villages with at least one malaria case during the low transmission season of the previous year; b) villages ranked highest in terms of incidence during the high transmission season of the previous year; c) villages ranked based on the degree of connectivity with adjacent populations.ResultsOur mathematical modeling, taking into account human mobility, showed that the intervention strategies targeting hotspots should be effective in reducing malaria incidence in both treated and untreated areas.ConclusionsMathematical simulations showed that targeted interventions allow increasing malaria elimination potential.


2007 ◽  
Vol 31 (6) ◽  
pp. 522-530 ◽  
Author(s):  
Kwang-Chul Noh ◽  
Hyeon-Cheol Lee ◽  
Dae-Young Kim ◽  
Myung-Do Oh

2019 ◽  
Vol 72 (1) ◽  
Author(s):  
Áine B. Collins ◽  
Michael L. Doherty ◽  
Damien J. Barrett ◽  
John F. Mee

Abstract In Autumn 2011, nonspecific clinical signs of pyrexia, diarrhoea, and drop in milk yield were observed in dairy cattle near the German town of Schmallenberg at the Dutch/German border. Targeted veterinary diagnostic investigations for classical endemic and emerging viruses could not identify a causal agent. Blood samples were collected from animals with clinical signs and subjected to metagenomic analysis; a novel orthobunyavirus was identified and named Schmallenberg virus (SBV). In late 2011/early 2012, an epidemic of abortions and congenital malformations in calves, lambs and goat kids, characterised by arthrogryposis and hydranencephaly were reported in continental Europe. Subsequently, SBV RNA was confirmed in both aborted and congenitally malformed foetuses and also in Culicoides species biting midges. It soon became evident that SBV was an arthropod-borne teratogenic virus affecting domestic ruminants. SBV rapidly achieved a pan-European distribution with most countries confirming SBV infection within a year or two of the initial emergence. The first Irish case of SBV was confirmed in the south of the country in late 2012 in a bovine foetus. Since SBV was first identified in 2011, a considerable body of scientific research has been conducted internationally describing this novel emerging virus. The aim of this systematic review is to provide a comprehensive synopsis of the most up-to-date scientific literature regarding the origin of SBV and the spread of the Schmallenberg epidemic, in addition to describing the species affected, clinical signs, pathogenesis, transmission, risk factors, impact, diagnostics, surveillance methods and control measures. This review also highlights current knowledge gaps in the scientific literature regarding SBV, most notably the requirement for further research to determine if, and to what extent, SBV circulation occurred in Europe and internationally during 2017 and 2018. Moreover, recommendations are also made regarding future arbovirus surveillance in Europe, specifically the establishment of a European-wide sentinel herd surveillance program, which incorporates bovine serology and Culicoides entomology and virology studies, at national and international level to monitor for the emergence and re-emergence of arboviruses such as SBV, bluetongue virus and other novel Culicoides-borne arboviruses.


2002 ◽  
Vol 41 (Part 1, No. 9) ◽  
pp. 5835-5840
Author(s):  
Kiminobu Akeno ◽  
Munehiro Ogasawara ◽  
Kenji Ooki ◽  
Toru Tojo ◽  
Ryoichi Hirano ◽  
...  

Author(s):  
Mark A. van de Kerkhof ◽  
Tjarko van Empel ◽  
Michael Lercel ◽  
Christophe Smeets ◽  
Ferdi van de Wetering ◽  
...  

Author(s):  
Mark A. van de Kerkhof ◽  
Andrei Yakunin ◽  
Vladimir Kvon ◽  
Ferdi van de Wetering ◽  
Selwyn Cats ◽  
...  

2014 ◽  
Vol 35 (7) ◽  
pp. 833-838 ◽  
Author(s):  
Pascale Trépanier ◽  
Caroline Quach ◽  
Milagros Gonzales ◽  
Élise Fortin ◽  
Mohammed Kaouache ◽  
...  

ObjectiveDespite surveillance, the Quebec Healthcare-Associated Infections Surveillance Program saw no improvement in vascular access–associated bloodstream infections in hemodialysis (HD). We aimed to determine the infection control measures recommended and implemented in Quebec’s HD units, compliance of local protocols to infection control practice guidelines, and reasons behind the low prevalence of arteriovenous fistulas.MethodsAn online survey was elaborated on the basis of the Centers for Disease Control and Prevention (CDC) and National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines. The questionnaire was validated (construct, content, face validity, and reliability) and sent to all HD units in Quebec (n = 40). Results were analyzed using descriptive statistics, linear regression, and Poisson regression.ResultsThirty-seven (93%) of 40 HD units participated. Thirty (94%) of the 32 centers where central catheters are inserted have written insertion protocols. Compliance with practice guidelines is good, except for full-body draping during catheter insertion (79%) and ointment use at insertion site (3%). Prevention measures for catheter maintenance are in accordance with guidelines, except for skin disinfection with at least 0.5% chlorhexidine and 70% alcohol (67% compliance) and regular antiseptic ointment use at the insertion site (3%). Before fistula cannulation, skin preparation is suboptimal; forearm hygiene is performed in only 61% of cases. Several factors explain the low rate of fistulas, including patient preference (69%) and lack of surgical resources (39%; P = .01).ConclusionsImprovement in standardization of care according to practice guidelines is necessary. Fistula rate could be increased by improving access to surgical resources and patient education. Strategies are now being elaborated to address these findings.


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