[Research progress on distribution characteristics and health risk assessment of bioaerosols in medical institutions].

Bioaerosols in healthcare facilities are closely related to the health of medical staff and patients. Inhalation of microbial aerosol particles can lead to both infectious and non-infectious diseases. However, a systematic summary of bioaerosol types, sources, impact factors and health risk analysis is lacking.This article condutcted a literature review to understand the distribution characteristics, sources, influencing factors and health risks of bioaerosols in healthcare facilities, both domestically and internationally. The goal is to increase awareness of the distribution characteristics of bioaerosols in healthcare facilities and health risk of bioaerosols in medical institutions. This article also provides a reference for prevention and control of bioaerosols.

An in vitro visual study of fugitive aerosols released during aerosol therapy to an invasively ventilated simulated patient.

COVID-19 can cause serious respiratory complications resulting in the need for invasive ventilatory support and concurrent aerosol therapy. Aerosol therapy is considered a high risk procedure for the transmission of patient derived infectious aerosol droplets. Critical-care workers are considered to be at a high risk of inhaling such infectious droplets. The objective of this work was to use noninvasive optical methods to visualize the potential release of aerosol droplets during aerosol therapy in a model of an invasively ventilated adult patient. The noninvasive Schlieren imaging technique was used to visualize the movement of air and aerosol. Three different aerosol delivery devices: (i) a pressurized metered dose inhaler (pMDI), (ii) a compressed air driven jet nebulizer (JN), and (iii) a vibrating mesh nebulizer (VMN), were used to deliver an aerosolized therapeutic at two different positions: (i) on the inspiratory limb at the wye and (ii) on the patient side of the wye, between the wye and endotracheal tube, to a simulated intubated adult patient. Irrespective of position, there was a significant release of air and aerosol from the ventilator circuit during aerosol delivery with the pMDI and the compressed air driven JN. There was no such release when aerosol therapy was delivered with a closed-circuit VMN. Selection of aerosol delivery device is a major determining factor in the release of infectious patient derived bioaerosol from an invasively mechanically ventilated patient receiving aerosol therapy.

Risk assessment of components in tobacco smoke and e-cigarette aerosols: a pragmatic choice of dose metrics.

BACKGROUND: Risk assessment of individual tobacco smoke components is important for the purpose of prioritization or selecting chemicals for monitoring products. Smoking is characterized by a highly varying, intermittent exposure and the challenge is to choose the most appropriate dose metric. METHODS: Generally, average daily exposure estimates are used as dose metric, without considering temporal determinants. The applicability hereof is discussed in the context of choosing dose metrics for local respiratory tract effects and for systemic effects in a smoking scenario or for the use of e-cigarettes. RESULTS: Using average daily exposure estimates for the smoking scenario can lead to erroneous risk evaluations for several reasons. Inhaled peak air concentrations during a puff can be two to three orders of magnitude higher than the calculated average daily inhaled concentration, which may impact the assessment of both systemic and local health effects. A pragmatic risk assessment is proposed, based on the Margin of Exposure (MoE) approach. The choice of an appropriate dose metric, such as inhaled concentration, inhaled dose or absorbed dose, depends on the type of effect. Temporal characteristics should be considered in the final step of the MoE approach, as is illustrated by two cases, glycerol and benzene. CONCLUSION: The choice of an appropriate dose metric and inclusion of temporal determinants are important aspects in the risk assessment of individual smoke components. The proposed MoE approach provides the opportunity to weigh smoking-related exposure characteristics during the final step of the risk evaluation.

The in vitro ToxTracker and Aneugen Clastogen Evaluation extension assay as a tool in the assessment of relative genotoxic potential of e-liquids and their aerosols.

In vitro (geno)toxicity assessment of electronic vapour products (EVPs), relative to conventional cigarette, currently uses assays, including the micronucleus and Ames tests. Whilst informative on induction of a finite endpoint and relative risk posed by test articles, such assays could benefit from mechanistic supplementation. The ToxTracker and Aneugen Clastogen Evaluation analysis can indicate the activation of reporters associated with (geno)toxicity, including DNA damage, oxidative stress, the p53-related stress response and protein damage. Here, we tested for the different effects of a selection of neat e-liquids, EVP aerosols and Kentucky reference 1R6F cigarette smoke samples in the ToxTracker assay. The assay was initially validated to assess whether a mixture of e-liquid base components, propylene glycol (PG) and vegetable glycerine (VG) had interfering effects within the system. This was achieved by spiking three positive controls into the system with neat PG/VG or phosphate-buffered saline bubbled (bPBS) PG/VG aerosol (nicotine and flavour free). PG/VG did not greatly affect responses induced by the compounds. Next, when compared to cigarette smoke samples, neat e-liquids and bPBS aerosols (tobacco flavour; 1.6% freebase nicotine, 1.6% nicotine salt or 0% nicotine) exhibited reduced and less complex responses. Tested up to a 10% concentration, EVP aerosol bPBS did not induce any ToxTracker reporters. Neat e-liquids, tested up to 1%, induced oxidative stress reporters, thought to be due to their effects on osmolarity in vitro. E-liquid nicotine content did not affect responses induced. Additionally, spiking nicotine alone only induced an oxidative stress response at a supraphysiological level. In conclusion, the ToxTracker assay is a quick, informative screen for genotoxic potential and mechanisms of a variety of (compositionally complex) samples, derived from cigarettes and EVPs. This assay has the potential for future application in the assessment battery for next-generation (smoking alternative) products, including EVPs.

Propensity of aerosol and droplet creation during oculoplastic procedures: A risk assessment with high-speed imaging amidst COVID-19 pandemic.

PURPOSE: The study uses principles of liquid and gas mechanics to verify and quantify the generation of aerosols in oculoplastic procedures, namely surgery using a scalpel, electrosurgical device, and a mechanized drill. METHODS: Surgical techniques were performed ex vivo using the electrosurgical device, scalpel, and mechanized drill on the muscle and bone of commercially available chicken. The liquid and gas dynamics were observed using a high-speed high-resolution Photron SA5 camera (0.125 to 8 ms temporal resolution, 0.016 to 0.054 mm/pixel spatial resolution) and stroboscopic lighting (Veritas 120 E LED Constellation). The analysis was performed using in-house algorithms and ImageJ software. RESULTS: The use of a mechanized drill at 35000 rpm and a 3 mm fluted burr generated aerosol with particle size 50 to 550 microns with a spread of 1.8 m radius. Surgical smoke was generated by an electrosurgical device in both cutting and coagulation modes. Dispersion of the smoke could be controlled significantly by the use of suction, mean smoke spread ratio being 0.065 without suction and 0.002 with use of suction within 2 cm. CONCLUSION: The quantification of the aerosol generation will help surgeons take practical decisions in their surgical techniques in the pandemic era.

[Delivery of oral health in andalusian health service on the de-escalation of SARS-CoV-2]. / Actividad asistencial en Unidades de Salud Bucodental del Servicio Andaluz de Salud durante la desescalada del SARS-CoV-2.

The pandemic declared by SARS-CoV-2 has meant a crisis in the health system that forced the urgent implementation of preventive public health measures. The respiratory transmission virus remains stable on surfaces, being able to spread by air in respiratory droplets or in procedures that generate aerosols. Dental activity is one of the professional sectors with the highest exposure index, both due to the generation of aerosols in most interventions, as well as the impossibility of maintaining a safe distance between patients and professionals. The postponement of scheduled and non-urgent healthcare activities in dental offices is one of the measures implemented to reduce the risk that it posed for the health and well-being of citizens. This report addresses the recommendations and measures to be taken into account to minimize risks in the Oral Health Units of the Andalusian Public Health System, to address the oral pathology of the population assigned in the scenario of improvement of the pandemic and its partial lack of confinement.

La pandemia declarada por SARS-CoV-2 ha supuesto una crisis en el sistema sanitario que obligó a la implementación urgente de medidas preventivas de salud pública. El virus de transmisión respiratoria permanece estable en superficies, pudiéndose propagar por vía aérea en gotitas respiratorias o en procedimientos que generan aerosoles. La actividad odontológica es uno de los sectores profesionales con mayor índice de exposición, tanto por la generación de aerosoles en la mayor parte de las intervenciones, así como por la imposibilidad de mantener una distancia de seguridad entre paciente y profesionales. El aplazamiento de las actividades sanitarias programadas y no urgentes en los gabinetes dentales son una de las medidas implantadas para disminuir el riesgo que supone para la salud y el bienestar de la ciudadanía. Este informe abordó las recomendaciones y medidas a tener en cuenta para minimizar riesgos en las Unidades de Salud Bucodental del Sistema Sanitario Público Andaluz, para atender la patología bucodental de la población asignada en el escenario de mejora de la pandemia y su desconfinamiento parcial.

A Positive-Pressure Environment Disposable Shield (PEDS) for COVID-19 Health Care Worker Protection.

The COVID-19 pandemic has strained health care system resources and reduced the availability of life-sustaining and medical-grade personal protective equipment (PPE) though the combination of increased demand and disrupted manufacturing supply chains. As a result of these shortages, many health care providers have temporarily used largely untested, improvised PPE (iPPE). Lack of quality control for makeshift PPE and frequent repurposing of used items to conserve supplies increase both the risk of provider infection and nosocomial spread to uninfected patients. One strategy to reduce risk of infection and preserve existing equipment is the implementation of secondary barrier devices placed directly over patients or providers. The authors describe an inexpensive, disposable, positive-pressure head isolation unit that can be rapidly constructed from materials readily available in nearly all health care settings for under five US dollars. The unit was successfully deployed in Taiwan during the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak, and again during the COVID-19 pandemic. The iPPE worn directly by the health care workers (HCWs) can be donned prior to patient contact in the presence of an air source. This strategy may be more protective than a covering placed over the patient in an aerosol-generating environment, which requires the HCW to be in close contact with the patient prior to securing the protective device.

Assessment of functional nanomaterials in medical applications: can time mend public and occupational health risks related to the products' fate?

Surface coatings are one promising option to prevent bacterial adhesion and biofilm formation given the prevalence of antibiotic resistant bacterial strains. Titanium dioxide (TiO2) is presently considered to be the only photocatalytic material suitable for commercial use, although the toxicity risks of TiO2, particularly in its nanoparticulate form, have not been fully addressed. The aim of this study was to determine release of nanoparticles (NPs) from functional materials for medical applications and their aerosol formation. Further, the fate of the material with respect to its product lifetime was investigated. The present study examined the risk of NP exposure since released submicronic and inhalable manufactured nano-objects, their agglomeraates or aggregates containing Ti were detected. The coating of the material magnifies its emission levels when comparing the obtained product properties to those of an uncoated sample. The evolution of release tendecy with the material's time of use shows that release does not vanish upon continuous material losses induced by the release, thus the risk does not diminish with time. Consequently, this nanomaterial TiO2 needs to be avoided in healthcare settings, or, alternatively, new TiO2-deposition techniques are required to be developed.

Heat-not-burn tobacco product use in Japan: its prevalence, predictors and perceived symptoms from exposure to secondhand heat-not-burn tobacco aerosol.

OBJECTIVES: A heat-not-burn (HNB) tobacco product, IQOS, was first launched in Japan and Italy as test markets and is currently in commerce in 30 countries. Using two data sources, we examined interest in HNB tobacco (IQOS, Ploom and glo), its prevalence, predictors of its use and symptoms from exposure to secondhand HNB tobacco aerosol in Japan, where HNB tobacco has been sold since 2014. METHODS: Population interest in HNB tobacco was explored using Google search query data. Prevalence of HNB tobacco current use (ie, use in the previous 30 days) was calculated using a longitudinal internet survey of 8240 individuals (15-69 years old in 2015) followed up to 2017. Rates of perceived symptoms from exposure to exhaled aerosol of others' HNB tobacco were also calculated. RESULTS: The largest internet search volume for IQOS occurred in April 2016 in the week after a popular national entertainment TV show introduced IQOS. For Ploom and glo, search volumes have remained limited since their launch. Prevalence of IQOS users increased from 0.3% in January-February 2015 to 0.6% in January-February 2016 and up to 3.6% in January-February 2017, while estimated rates of use of other HNB tobacco products remained low in 2017. Respondents who had seen the TV programme in 2016 were more likely to have used IQOS than those who had not seen it (10.3% vs 2.7%). Among never-smokers who had been exposed to secondhand HNB tobacco aerosol, nearly half reported at least one acute symptom, although these symptoms were not serious. CONCLUSIONS: A popular TV programme triggered IQOS diffusion in Japan. Extrapolating from survey results to the general population, around 3.1 million people currently use IQOS in Japan. Tobacco control organisations and governments should closely monitor HNB tobacco and consider how to regulate it.

Assessment of workers' exposure to microorganisms when using biological degreasing stations.

Biological degreasing stations (BDSs) are used by mechanics. These BDSs use a water-based solution with a microbial degradation process. Occupational exposure during the use of BDSs has not been reported and few studies have identified the bacteria present. The objectives were to measure the concentration of microorganisms during BDSs' use and monitor the bacterial community in the liquid over time. Five mechanical workshops were studied. Six 30-min samples were taken at each workshop over one year. Bioaerosols in the ambient air samples were collected with Andersen impactors near the BDS Bioaerosols in the workers' breathing zone (WBZ) were collected on filters. Fresh bio-degreasing fluids were collected from unopened containers, and used bio-degreasing fluids were collected in the BDS. The results show that the use of BDSs does not seem to increase bioaerosols concentrations in the WBZ (concentrations lower than 480 CFU/m3) and that the bacterial communities (mainly yeasts, Bacillus subtilis and Pseudomonas aeruginosa) in the bio-degreasing fluids change through time and differ from the original community (B. subtilis). This study established that workers using BDSs were exposed to low levels of bioaerosols. No respiratory protection is recommended based on bioaerosols concentrations, but gloves and strict personal hygiene practices are essential.

Health Impact Assessment of Asian Dust/Cross-border Air Pollutant and Necessary Preventive Measure.

The health effects of Asian dust (mineral dust) originating from dry lands such as the Gobi Desert and Taklamakan Desert have recently been a concern. In addition to Asian dust, transboundary airborne microparticles that reach Japan include various types of aerosol, such as artificial air pollutants and smoke from combustion. They originate from densely populated areas and are transported along the same route as Asian dust. We analyzed environmental factors and subjective symptoms involving the respiratory organ, nose, eyes, and skin using a conventional equation for estimation, and found that symptoms with a significant risk of worsening varied according to the type of pollutants reaching Japan. We also analyzed the synergistic effects of Asian dust and pollens on nasal symptoms using a two-pollutant model. The odds ratio for symptoms at the time of arrival of a high concentration of Asian dust was 1.37 (95% confidence interval: 1.19-1.58), but the odds ratio adjusted for pollens was 1.18 (95% confidence interval: 1.04-1.34). Although the influence on nasal symptoms overlapped somewhat between Asian dust and pollens, that of Asian dust remained significant. Regarding preventive measures against symptoms, we examined the rate of particle leakage into masks. We found that it is important to wear a mask that fits an individual's facial features and has no gap between the face and the mask. In addition, we report our attempt to construct models for predicting aerosol arrival and forecasting health to establish preventive measures against aerosols.

Aerosolised liposomal amphotericin B to prevent aspergillosis in acute myeloid leukaemia: Efficacy and cost effectiveness in real-life.

Chemotherapy-induced neutropenia can be complicated by invasive pulmonary aspergillosis (IPA). In 2008, liposomal amphotericin B (L-AmB) inhalation was shown to prevent IPA in a placebo-controlled trial. Patients with acute myeloid leukaemia (AML) are the subset of haematology patients at high risk for IPA. In 2008, L-AmB inhalation prophylaxis became the standard of care for all AML patients in Erasmus MC. In this study, the efficacy and cost effectiveness of L-AmB inhalation were evaluated in a prospective cohort of AML patients. In total, 127 consecutive AML patients received chemotherapy and prophylactically inhaled L-AmB during their first and second chemotherapy cycles; 108 patients treated for AML at the same sites from 2005-2008 served as controls. A standardised diagnostic protocol was used and probable/proven IPA served as the primary endpoint. Diagnostic and therapeutic costs were also comprehensively analysed and compared. A significant decrease in probable/proven IPA in the L-AmB inhalation group was observed (L-AmB 9.5% vs. controls 23.4%; P=0.0064). Systemic antifungal therapy given at any time during the entire AML therapy decreased from 52.8% to 29.9%. Per-patient equipment and drug costs for L-AmB inhalation (1292 €/patient) were more than compensated for by a decrease in costs for diagnostics and therapeutic voriconazole use (-1816 €/patient). No serious adverse events related to L-AmB inhalation were observed. In an unselected AML patient group, L-AmB inhalation resulted in a significant and substantial decrease in IPA and was cost saving. Now that azole resistance is more frequent, non-azole-based prophylaxis may become an attractive strategy.

Metrological assessment of a portable analyzer for monitoring the particle size distribution of ultrafine particles.

Adverse health effects caused by worker exposure to ultrafine particles have been detected in recent years. The scientific community focuses on the assessment of ultrafine aerosols in different microenvironments in order to determine the related worker exposure/dose levels. To this end, particle size distribution measurements have to be taken along with total particle number concentrations. The latter are obtainable through hand-held monitors. A portable particle size distribution analyzer (Nanoscan SMPS 3910, TSI Inc.) was recently commercialized, but so far no metrological assessment has been performed to characterize its performance with respect to well-established laboratory-based instruments such as the scanning mobility particle sizer (SMPS) spectrometer. The present paper compares the aerosol monitoring capability of the Nanoscan SMPS to the laboratory SMPS in order to evaluate whether the Nanoscan SMPS is suitable for field experiments designed to characterize particle exposure in different microenvironments. Tests were performed both in a Marple calm air chamber, where fresh diesel particulate matter and atomized dioctyl phthalate particles were monitored, and in microenvironments, where outdoor, urban, indoor aged, and indoor fresh aerosols were measured. Results show that the Nanoscan SMPS is able to properly measure the particle size distribution for each type of aerosol investigated, but it overestimates the total particle number concentration in the case of fresh aerosols. In particular, the test performed in the Marple chamber showed total concentrations up to twice those measured by the laboratory SMPS-likely because of the inability of the Nanoscan SMPS unipolar charger to properly charge aerosols made up of aggregated particles. Based on these findings, when field test exposure studies are conducted, the Nanoscan SMPS should be used in tandem with a condensation particle counter in order to verify and correct the particle size distribution data.