Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Hydrothermal synthesis of magnetite nanoparticles as MRI contrast agents

Magnetite (Fe 3O 4) nanoparticles prepared using hydrothermal approach were employed to study their potential application as magnetic resonance imaging (MRI) contrast agent. The hydrothermal process involves precursors FeCl 2·4H 2O and FeCl 3 with NaOH as reducing agent to initiate the precipitation of Fe 3O 4, followed by hydrothermal treatment to produce nano-sized Fe 3O 4. Chitosan (CTS) was coated onto the surface of the as-prepared Fe 3O 4 nanoparticles to enhance its stability and biocompatible properties. The size distribution of the obtained Fe 3O 4 nanoparticles was examined using transmission electron microscopy (TEM). The cubic inverse spinel structure of Fe 3O 4 nanoparticles was confirmed by X-ray diffraction technique (XRD). Fourier transform infrared (FTIR) spectrum indicated the presence of the chitosan on the surface of the Fe 3O 4 nanoparticles. The superparamagnetic behaviour of the produced Fe 3O 4 nanoparticles at room temperature was elucidated using a vibrating sample magnetometer (VSM). From the result of custom made phantom study of magnetic resonance (MR) imaging, coated Fe 3O 4 nanoparticles have been proved to be a promising contrast enhanced agent in MR imaging. © 2010 Elsevier Ltd and Techna Group S.r.l

Morphological studies of randomized dispersion magnetite nanoclusters coated with silica

In this study, we report a simple way to produce randomized dispersion magnetite nanoclusters coated with silica (RDMNS) via Stöber process with minor modifications. The morphology of silica coated magnetite nanoclusters was emphasized by studying various reaction parameters including alcohols with different polarities as co-solvents, concentration of alcohol-water, concentration of alkaline catalyst (ammonia), and concentration of TEOS monomer. The results of transmission electron microscope (TEM) showed that the sizes and morphological behaviour of the magnetite nanoclusters vary accordingly with the different reaction parameters investigated. The results showed that ethanol would be the best candidate as co-solvent in the preparation of randomized dispersion magnetite nanoclusters. Besides, the optimum alcohol-water ratio has been determined to be 70-30 v/v as this concentration range could render desired shape of randomized dispersion magnetite nanoclusters. The volume of ammonia (NH 3) catalyst in the reaction media also strongly governs the formation of silica coated magnetite nanoclusters in a desired shape. Apart from that, the addition of TEOS monomer into the reaction media has to be well-controlled as the excess amount of monomer added might affect the thickness of the silica layer that is coated on the magnetite nanoparticles. Prior to silica coating, the bare magnetite nanoparticles were first treated with trisodium citrate (0.5 M) to enhance the particles' dispersibility. Improvement in the size distribution and dispersibility of the magnetite nanoparticles after the citrate treatment has been examined using TEM. The XRD results show that the magnetite samples retained good crystallinity although they have been surface-modified with citrate group and silica. The Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA) prove that the magnetite nanoparticles have been successfully coated with citrate and silica. The superparamagnetic behaviour of the magnetite samples was confirmed by VSM. The produced silica coated magnetite nanoclusters possess great potential to be applied in bio-medical research and clinical diagnosis application. © 2010 Elsevier Ltd and Techna Group S.r.l