Comparison between visual analysis and microscope assessment of surgical instrument cleanliness from sterile service departments
ABSTRACT Modern hospital sterile service departments (SSDs) routinely inspect instruments visually to assess the degree of contamination present after the washer/disinfector cycle. We aimed to test the effectiveness and reliability of this method. Surgical instrument sets were obtained from nine anonymous National Health Service (NHS) Primary Care Trust SSDs to investigate the efficacy of 'in-place' cleaning procedures. The instruments were first inspected visually, followed by a novel technique called episcopic differential interference contrast microscopy. This was combined with a sensitive fluorescent reagent, SYPRO Ruby, to rapidly visualise and assess contamination levels on the medical devices. The application of a Contamination Index (0-4) for both proteinaceous and non-proteinaceous deposits on the surface allowed quantitative assessment. Close correlation was seen for simple instruments between visual assessment and microscopic analysis. For more complex instruments, however, there was a marked difference between the two assessment techniques and the microscopy procedure showed areas of proteinaceous and non-proteinaceous crystalline soiling that was difficult or impossible to see by eye. Visual assessment of cleaning is fraught with possible error. This survey shows how large amounts of contamination could pass undetected using such antiquated methods. The new methodology applied in the assessment of surface contamination is rapid and generally applicable and could be used more widely for routine monitoring of instrument cleanliness.
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ABSTRACT: More than 50 million surgical and invasive medical procedures—includ-ing approximately 5 million gastroin-testinal endoscopies—are performed each year in the US alone. During these procedures, the close contact between surgical instruments and the exposed tissues of the patient can constitute an additional health risk due to the increased possibility of contamination by pathogens introduced by the surgi-cal device itself: if the instruments used are not properly disinfected or steri-lized, the risks of transmission of infection from person-to-person (e.g., hepatitis B virus) or of introducing environmental pathogens (e.g., Pseu-domonas aeruginosa) become high. The seriousness of this problem can be clearly seen by considering that the number of Hospital Acquired Infections (HAI) is estimated to be of the order of 2 million each year in the US. Moreover, the number of these infections which, directly or indirectly, may be linked with patient death in U.S. hospitals is thought to have been about 10 000 in 2002  for a cost of the order of 5–7 b$. Similar figures are also reported for the UK and France, with 100 000 HAI leading to about 5 000 deaths in 2000 for UK  and 4 000 for France.  These alarming figures are also reflected in the statistics of other European countries and serve to underline the importance of develop-ing and applying robust sterilization and decontamination processes and procedures. Recent studies in the UK have shown that significant quantities of residues composed of salts, proteins and undefined organic matter can remain on surgical instruments even after applying the normal cleaning and sterilization procedures adopted in Sterile Service Departments. Plasma Processes and Polymers 06/2012; 9(6). DOI:10.1002/ppap.201200034 · 3.73 Impact Factor
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ABSTRACT: TiO2 thin films are of great interest as biocompatible coatings and also as photocatalytic self-cleaning and antimicrobial coatings. In this work we used β-amyloid as a model for infectious protein to investigate the attachment and photocatalytic degradation. TiO2 films were prepared on stainless steel substrates using magnetron sputtering. The films were characterised before and after exposure to β-amyloid (1–42), using XRD, Raman spectroscopy, XPS and AFM. The TiO2 film was mostly composed of the anatase phase with a relatively high surface roughness. The presence of Raman peaks at 1668 cm− 1 and 1263 cm− 1, with the XPS spectral feature for nitrogen at 400 eV, confirmed the adsorption of amyloid on surface. Following exposure of the β-amyloid contaminated TiO2 to UV-B irradiation a slight shift of amide modes was observed. Furthermore, the amide I spectra show an overall decrease in α-helix content with presence of a minor peak around 1591 cm− 1, which is related to tryptophanyl and tyrosinyl radicals, which can lead to conformational change of β-amyloid. The C1s band at 292.2 eV suggests the formation of free carboxylic acid. The loss in the crucial structure of β-amyloid leads to reduce the fibril formation, thought to be induced through a photocatalytic process.Materials Science and Engineering C 06/2014; 39:227–234. DOI:10.1016/j.msec.2014.03.011 · 2.74 Impact Factor