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1.
Anesthesiology ; 134(1): 61-71, 2021 01 01.
Article in English | MEDLINE | ID: covidwho-2161186

ABSTRACT

BACKGROUND: Disease severity in coronavirus disease 2019 (COVID-19) may be associated with inoculation dose. This has triggered interest in intubation barrier devices to block droplet exposure; however, aerosol protection with these devices is not known. This study hypothesized that barrier devices reduce aerosol outside of the barrier. METHODS: Aerosol containment in closed, semiclosed, semiopen, and open barrier devices was investigated: (1) "glove box" sealed with gloves and caudal drape, (2) "drape tent" with a drape placed over a frame, (3) "slit box" with armholes and caudal end covered by vinyl slit diaphragms, (4) original "aerosol box," (5) collapsible "interlocking box," (6) "simple drape" over the patient, and (7) "no barrier." Containment was investigated by (1) vapor instillation at manikin's right arm with video-assisted visual evaluation and (2) submicrometer ammonium sulfate aerosol particles ejected through the manikin's mouth with ventilation and coughs. Samples were taken from standardized locations inside and around the barriers using a particle counter and a mass spectrometer. Aerosol evacuation from the devices was measured using standard hospital suction, a surgical smoke evacuator, and a Shop-Vac. RESULTS: Vapor experiments demonstrated leakage via arm holes and edges. Only closed and semiclosed devices and the aerosol box reduced aerosol particle counts (median [25th, 75th percentile]) at the operator's mouth compared to no barrier (combined median 29 [-11, 56], n = 5 vs. 157 [151, 166], n = 5). The other barrier devices provided less reduction in particle counts (133 [128, 137], n = 5). Aerosol evacuation to baseline required 15 min with standard suction and the Shop-Vac and 5 min with a smoke evacuator. CONCLUSIONS: Barrier devices may reduce exposure to droplets and aerosol. With meticulous tucking, the glove box and drape tent can retain aerosol during airway management. Devices that are not fully enclosed may direct aerosol toward the laryngoscopist. Aerosol evacuation reduces aerosol content inside fully enclosed devices. Barrier devices must be used in conjunction with body-worn personal protective equipment.


Subject(s)
Aerosols/analysis , COVID-19/prevention & control , Occupational Exposure/analysis , Occupational Exposure/prevention & control , Personal Protective Equipment , Aerosols/adverse effects , Cough/prevention & control , Cough/virology , Health Personnel , Humans , Intubation, Intratracheal/adverse effects
2.
PLoS One ; 17(6): e0268974, 2022.
Article in English | MEDLINE | ID: covidwho-1885351

ABSTRACT

OBJECTIVE: The coronavirus disease pandemic has raised concerns regarding the transmission of infections to healthcare workers. We developed a new protective device to reduce the risk of aerosol diffusion and droplet infection among healthcare workers. Here, we report the results of a theoretical evaluation of the efficacy of this device. METHODS: We used suction-capable masks with and without rubber slits, sleeves for the insertion section of endoscopes and treatment tools, and a cover for the control section of the endoscope. To simulate droplet spread from patients, we created a droplet simulation model and an aerosol simulation model. The results with and without the devices attached and with and without the suction were compared. RESULTS: The droplet simulation model showed a 95% reduction in droplets with masks with rubber slits; furthermore, a reduction of 100% was observed when the insertion sleeve was used. Evaluation of aerosol simulation when suction was applied revealed an aerosol reduction of 98% and >99% with the use of the mask without rubber slits and with the combined use of the mask and insertion sleeve, respectively. The elimination of droplet emission upon instrument removal confirmed that the instrument sleeve prevented the diffusion of droplets. The elimination of droplets upon repeated pressing of the suction button confirmed that the cover prevented the diffusion of droplets. CONCLUSION: We developed a device for infection control, in collaboration with a gastrointestinal endoscopist and Olympus Medical Systems Corporation, that was effective in reducing droplet and aerosol diffusion in this initial theoretical assessment.


Subject(s)
Otolaryngology , Rubber , Aerosols , Humans , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Pandemics/prevention & control , Protective Devices
3.
Environ Sci Pollut Res Int ; 28(30): 40460-40473, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-2115871

ABSTRACT

In a post-pandemic scenario, indoor air monitoring may be required seeking to safeguard public health, and therefore well-defined methods, protocols, and equipment play an important role. Considering the COVID-19 pandemic, this manuscript presents a literature review on indoor air sampling methods to detect viruses, especially SARS-CoV-2. The review was conducted using the following online databases: Web of Science, Science Direct, and PubMed, and the Boolean operators "AND" and "OR" to combine the following keywords: air sampler, coronavirus, COVID-19, indoor, and SARS-CoV-2. This review included 25 published papers reporting sampling and detection methods for SARS-CoV-2 in indoor environments. Most of the papers focused on sampling and analysis of viruses in aerosols present in contaminated areas and potential transmission to adjacent areas. Negative results were found in 10 studies, while 15 papers showed positive results in at least one sample. Overall, papers report several sampling devices and methods for SARS-CoV-2 detection, using different approaches for distance, height from the floor, flow rates, and sampled air volumes. Regarding the efficacy of each mechanism as measured by the percentage of investigations with positive samples, the literature review indicates that solid impactors are more effective than liquid impactors, or filters, and the combination of various methods may be recommended. As a final remark, determining the sampling method is not a trivial task, as the samplers and the environment influence the presence and viability of viruses in the samples, and thus a case-by-case assessment is required for the selection of sampling systems.


Subject(s)
Air Pollution, Indoor , COVID-19 , Aerosols , Humans , Pandemics , SARS-CoV-2
4.
Ann Intern Med ; 173(3): 204-216, 2020 08 04.
Article in English | MEDLINE | ID: covidwho-2110840

ABSTRACT

BACKGROUND: Mechanical ventilation is used to treat respiratory failure in coronavirus disease 2019 (COVID-19). PURPOSE: To review multiple streams of evidence regarding the benefits and harms of ventilation techniques for coronavirus infections, including that causing COVID-19. DATA SOURCES: 21 standard, World Health Organization-specific and COVID-19-specific databases, without language restrictions, until 1 May 2020. STUDY SELECTION: Studies of any design and language comparing different oxygenation approaches in patients with coronavirus infections, including severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS), or with hypoxemic respiratory failure. Animal, mechanistic, laboratory, and preclinical evidence was gathered regarding aerosol dispersion of coronavirus. Studies evaluating risk for virus transmission to health care workers from aerosol-generating procedures (AGPs) were included. DATA EXTRACTION: Independent and duplicate screening, data abstraction, and risk-of-bias assessment (GRADE for certainty of evidence and AMSTAR 2 for included systematic reviews). DATA SYNTHESIS: 123 studies were eligible (45 on COVID-19, 70 on SARS, 8 on MERS), but only 5 studies (1 on COVID-19, 3 on SARS, 1 on MERS) adjusted for important confounders. A study in hospitalized patients with COVID-19 reported slightly higher mortality with noninvasive ventilation (NIV) than with invasive mechanical ventilation (IMV), but 2 opposing studies, 1 in patients with MERS and 1 in patients with SARS, suggest a reduction in mortality with NIV (very-low-certainty evidence). Two studies in patients with SARS report a reduction in mortality with NIV compared with no mechanical ventilation (low-certainty evidence). Two systematic reviews suggest a large reduction in mortality with NIV compared with conventional oxygen therapy. Other included studies suggest increased odds of transmission from AGPs. LIMITATION: Direct studies in COVID-19 are limited and poorly reported. CONCLUSION: Indirect and low-certainty evidence suggests that use of NIV, similar to IMV, probably reduces mortality but may increase the risk for transmission of COVID-19 to health care workers. PRIMARY FUNDING SOURCE: World Health Organization. (PROSPERO: CRD42020178187).


Subject(s)
Coronavirus Infections/transmission , Pneumonia, Viral/transmission , Respiration, Artificial/adverse effects , Respiration, Artificial/methods , Aerosols , Animals , Betacoronavirus , COVID-19 , Coronavirus Infections/mortality , Humans , Pandemics , Pneumonia, Viral/mortality , Randomized Controlled Trials as Topic , SARS-CoV-2 , Severe Acute Respiratory Syndrome/transmission , Systematic Reviews as Topic , World Health Organization
5.
Emerg Infect Dis ; 28(10): 2016-2026, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2103284

ABSTRACT

Data on social contact patterns are widely used to parameterize age-mixing matrices in mathematical models of infectious diseases. Most studies focus on close contacts only (i.e., persons spoken with face-to-face). This focus may be appropriate for studies of droplet and short-range aerosol transmission but neglects casual or shared air contacts, who may be at risk from airborne transmission. Using data from 2 provinces in South Africa, we estimated age mixing patterns relevant for droplet transmission, nonsaturating airborne transmission, and Mycobacterium tuberculosis transmission, an airborne infection where saturation of household contacts occurs. Estimated contact patterns by age did not vary greatly between the infection types, indicating that widespread use of close contact data may not be resulting in major inaccuracies. However, contact in persons >50 years of age was lower when we considered casual contacts, and therefore the contribution of older age groups to airborne transmission may be overestimated.


Subject(s)
Mycobacterium tuberculosis , Respiratory Aerosols and Droplets , Aerosols , Models, Theoretical , South Africa/epidemiology
8.
Infect Control Hosp Epidemiol ; 41(11): 1258-1265, 2020 11.
Article in English | MEDLINE | ID: covidwho-2096345

ABSTRACT

BACKGROUND: The role of severe respiratory coronavirus virus 2 (SARS-CoV-2)-laden aerosols in the transmission of coronavirus disease 2019 (COVID-19) remains uncertain. Discordant findings of SARS-CoV-2 RNA in air samples were noted in early reports. METHODS: Sampling of air close to 6 asymptomatic and symptomatic COVID-19 patients with and without surgical masks was performed with sampling devices using sterile gelatin filters. Frequently touched environmental surfaces near 21 patients were swabbed before daily environmental disinfection. The correlation between the viral loads of patients' clinical samples and environmental samples was analyzed. RESULTS: All air samples were negative for SARS-CoV-2 RNA in the 6 patients singly isolated inside airborne infection isolation rooms (AIIRs) with 12 air changes per hour. Of 377 environmental samples near 21 patients, 19 (5.0%) were positive by reverse-transcription polymerase chain reaction (RT-PCR) assay, with a median viral load of 9.2 × 102 copies/mL (range, 1.1 × 102 to 9.4 × 104 copies/mL). The contamination rate was highest on patients' mobile phones (6 of 77, 7.8%), followed by bed rails (4 of 74, 5.4%) and toilet door handles (4 of 76, 5.3%). We detected a significant correlation between viral load ranges in clinical samples and positivity rate of environmental samples (P < .001). CONCLUSION: SARS-CoV-2 RNA was not detectable by air samplers, which suggests that the airborne route is not the predominant mode of transmission of SARS-CoV-2. Wearing a surgical mask, appropriate hand hygiene, and thorough environmental disinfection are sufficient infection control measures for COVID-19 patients isolated singly in AIIRs. However, this conclusion may not apply during aerosol-generating procedures or in cohort wards with large numbers of COVID-19 patients.


Subject(s)
Air Microbiology , Betacoronavirus/isolation & purification , Coronavirus Infections/transmission , Fomites/virology , Infection Control/methods , Patients' Rooms , Pneumonia, Viral/transmission , Adolescent , Adult , Aerosols , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/prevention & control , Female , Hospitalization , Humans , Male , Middle Aged , Pandemics/prevention & control , Pneumonia, Viral/diagnosis , Pneumonia, Viral/prevention & control , SARS-CoV-2 , Viral Load
10.
Gastroenterol Hepatol ; 43(8): 464-471, 2020 Oct.
Article in English, Spanish | MEDLINE | ID: covidwho-2095369

ABSTRACT

The SARS-CoV-2 pandemic is leading to high mortality and a global health crisis. The primary involvement is respiratory; however, the virus can also affect other organs, such as the gastrointestinal tract and liver. The most common symptoms are anorexia and diarrhea. In about half of the cases, viral RNA could be detected in the stool, which is another line of transmission and diagnosis. covid19 has a worse prognosis in patients with comorbidities, although there is not enough evidence in case of previous digestive diseases. Digestive endoscopies may give rise to aerosols, which make them techniques with a high risk of infection. Experts and scientific organizations worldwide have developed guidelines for preventive measures. The available evidence on gastrointestinal and hepatic involvement, the impact on patients with previous digestive diseases and operating guidelines for Endoscopy Units during the pandemic are reviewed.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/complications , Digestive System Diseases/etiology , Digestive System/virology , Pandemics , Pneumonia, Viral/complications , Aerosols , Angiotensin-Converting Enzyme 2 , Anorexia/etiology , Antiviral Agents/adverse effects , Betacoronavirus/isolation & purification , Betacoronavirus/physiology , COVID-19 , Cohort Studies , Coronavirus Infections/drug therapy , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Diarrhea/etiology , Digestive System Diseases/virology , Endoscopy, Digestive System/adverse effects , Feces/virology , Humans , Immunosuppressive Agents/adverse effects , Intestines/chemistry , Intestines/virology , Liver Diseases/etiology , Multicenter Studies as Topic , Pandemics/prevention & control , Peptidyl-Dipeptidase A/analysis , Peptidyl-Dipeptidase A/physiology , Personal Protective Equipment , Pneumonia, Viral/drug therapy , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Receptors, Virus/analysis , Receptors, Virus/physiology , Risk , SARS-CoV-2 , Universal Precautions
12.
Int J Environ Res Public Health ; 19(18)2022 Sep 08.
Article in English | MEDLINE | ID: covidwho-2047304

ABSTRACT

This study introduces a principle that unifies two experimental methods for evaluating airborne indoor virus-transmissions adapted to several ventilation measures. A first-time comparison of mechanical/natural ventilation and air purification with regard to infection risks is enabled. Effortful computational fluid dynamics demand detailed boundary conditions for accurate calculations of indoor airflows, which are often unknown. Hence, a suitable, simple and generalized experimental set up for identifying the spatial and temporal infection risk for different ventilation measures is more qualified even with unknown boundary conditions. A trace gas method is suitable for mechanical and natural ventilation with outdoor air exchange. For an accurate assessment of air purifiers based on filtration, a surrogate particle method is appropriate. The release of a controlled rate of either trace gas or particles simulates an infectious person releasing virus material. Surrounding substance concentration measurements identify the neighborhood exposure. One key aspect of the study is to prove that the requirement of concordant results of both methods is fulfilled. This is the only way to ensure that the comparison of different ventilation measures described above is reliable. Two examples (a two-person office and a classroom) show how practical both methods are and how the principle is applicable for different types and sizes of rooms.


Subject(s)
Air Filters , Air Pollution, Indoor , Aerosols , Air Pollution, Indoor/analysis , Filtration , Humans , Ventilation
13.
J Hosp Infect ; 115: 131-132, 2021 09.
Article in English | MEDLINE | ID: covidwho-1744208

Subject(s)
Travel , Aerosols , Humans
14.
Adv Drug Deliv Rev ; 189: 114527, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2060293

ABSTRACT

Lactose is the most commonly used excipient in carrier-based dry powder inhalation (DPI) formulations. Numerous inhalation therapies have been developed using lactose as a carrier material. Several theories have described the role of carriers in DPI formulations. Although these theories are valuable, each DPI formulation is unique and are not described by any single theory. For each new formulation, a specific development trajectory is required, and the versatility of lactose can be exploited to optimize each formulation. In this review, recent developments in lactose-based DPI formulations are discussed. The effects of varying the material properties of lactose carrier particles, such as particle size, shape, and morphology are reviewed. Owing to the complex interactions between the particles in a formulation, processing adhesive mixtures of lactose with the active ingredient is crucial. Therefore, blending and filling processes for DPI formulations are also reviewed. While the role of ternary agents, such as magnesium stearate, has increased, lactose remains the excipient of choice in carrier-based DPI formulations. Therefore, new developments in lactose-based DPI formulations are crucial in the optimization of inhalable medicine performance.


Subject(s)
Excipients , Lactose , Administration, Inhalation , Aerosols , Chemistry, Pharmaceutical , Drug Carriers , Dry Powder Inhalers , Humans , Particle Size , Powders
15.
Simul Healthc ; 17(1): 66-67, 2022 Feb 01.
Article in English | MEDLINE | ID: covidwho-2042677

ABSTRACT

SUMMARY STATEMENT: Simulation resources offer an opportunity to highlight aerosol dispersion within the operating room environment. We demonstrate our methodology with a supporting video that can offer operating room teams support in their practical understanding of aerosol exposure and the importance of personal protective equipment.


Subject(s)
Operating Rooms , Personal Protective Equipment , Aerosols , Health Personnel , Humans
16.
PLoS One ; 17(6): e0268542, 2022.
Article in English | MEDLINE | ID: covidwho-1987130

ABSTRACT

Proper respiratory tract protection is the key factor to limiting the rate of COVID-19 spread and providing a safe environment for health care workers. Traditional N95 (FFP2) respirators are not easy to regenerate and thus create certain financial and ecological burdens; moreover, their quality may vary significantly. A solution that would overcome these disadvantages is desirable. In this study a commercially available knit polyester fleece fabric was selected as the filter material, and a total of 25 filters of different areas and thicknesses were prepared. Then, the size-resolved filtration efficiency (40-400 nm) and pressure drop were evaluated at a volumetric flow rate of 95 L/min. We showed the excellent synergistic effect of expanding the filtration area and increasing the number of filtering layers on the filtration efficiency; a filter cartridge with 8 layers of knit polyester fabric with a surface area of 900 cm2 and sized 25 × 14 × 8 cm achieved filtration efficiencies of 98% at 95 L/min and 99.5% at 30 L/min. The assembled filter kit consists of a filter cartridge (14 Pa) carried in a small backpack connected to a half mask with a total pressure drop of 84 Pa at 95 L/min. In addition, it is reusable, and the filter material can be regenerated at least ten times by simple methods, such as boiling. We have demonstrated a novel approach for creating high-quality and easy-to-breathe-through respiratory protective equipment that reduces operating costs and is a green solution because it is easy to regenerate.


Subject(s)
COVID-19 , Respiratory Protective Devices , Aerosols , COVID-19/prevention & control , Equipment Design , Filtration/methods , Humans , Masks , Materials Testing/methods , Polyesters
18.
Br Dent J ; 230(5): 305, 2021 03.
Article in English | MEDLINE | ID: covidwho-1383093
19.
J Hazard Mater ; 422: 126783, 2022 01 15.
Article in English | MEDLINE | ID: covidwho-1347177

ABSTRACT

We designed a novel experimental set-up to pseudo-simultaneously measure size-segregated filtration efficiency (ηF), breathing resistance (ηP) and potential usage time (tB) for 11 types of face protective equipment (FPE; four respirators; three medical; and four handmade) in the submicron range. As expected, the highest ηF was exhibited by respirators (97 ± 3%), followed by medical (81 ± 7%) and handmade (47 ± 13%). Similarly, the breathing resistance was highest for respirators, followed by medical and handmade FPE. Combined analysis of efficiency and breathing resistance highlighted trade-offs, i.e. respirators showing the best overall performance across these two indicators, followed by medical and handmade FPE. This hierarchy was also confirmed by quality factor, which is a performance indicator of filters. Detailed assessment of size-segregated aerosols, combined with the scanning electron microscope imaging, revealed material characteristics such as pore density, fiber thickness, filter material and number of layers influence their performance. ηF and ηP showed an inverse exponential decay with time. Using their cross-over point, in combination with acceptable breathability, allowed to estimate tB as 3.2-9.5 h (respirators), 2.6-7.3 h (medical masks) and 4.0-8.8 h (handmade). While relatively longer tB of handmade FPE indicate breathing comfort, they are far less efficient in filtering virus-laden submicron aerosols compared with respirators.


Subject(s)
Masks , Respiratory Protective Devices , Aerosols , Filtration , Particle Size
20.
Respir Care ; 67(8): 1058-1060, 2022 08.
Article in English | MEDLINE | ID: covidwho-1979511
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