Review and demonstration of equations applied to models of filtering facepiece respirator particle capture efficiency.

The use of filtering facepiece respirators (FFRs) of various types increased dramatically by both workers and the public during the ongoing COVID-19 pandemic. This increased use has, likewise, instigated a proliferation of research on the qualities of FFRs. An aspect of FFR development and optimization involves the use of mathematical models that predict filter efficiency based on various filter characteristics while also considering a number of particle capture forces. An evaluation of current literature failed to identify a publication that provides a comprehensive assessment of the models developed to predict filter efficiency. The purpose of this review was, therefore, to describe models developed to include the forces associated with diffusion, interception, impaction, and electrostatic attraction as they contribute to the efficiency of an entire filter. The literature review was augmented with figures created with the use of many of the models discussed to compare different models of the same force as well as to illustrate the influence of electrostatic forces on overall filter efficiency.

The Impact of Ambient Environmental and Occupational Pollution on Respiratory Diseases.

Ambient pollutants and occupational pollutants may cause and exacerbate various lung and respiratory diseases. This review describes lung and respiratory diseases in relation to ambient pollutants, particularly particulate matter (PM2.5), and occupational air pollutants, excluding communicable diseases and indoor pollutants, including tobacco smoke exposure. PM2.5 produced by combustion is an important ambient pollutant. PM2.5 can cause asthma attacks and exacerbations of chronic obstructive pulmonary disease in the short term. Further, it not only carries a risk of lung cancer and death, but also hinders the development of lung function in children in the long term. It has recently been suggested that air pollution, such as PM2.5, is a risk factor for severe coronavirus disease (COVID-19). Asbestos, which causes asbestosis, lung cancer, and malignant mesothelioma, and crystalline silica, which cause silicosis, are well-known traditional occupational pollutants leading to pneumoconiosis. While work-related asthma (WRA) is the most common occupational lung disease in recent years, many different agents cause WRA, including natural and synthetic chemicals and irritant gases. Primary preventive interventions that increase awareness of pollutants and reduce the development and exacerbation of diseases caused by air pollutants are paramount to addressing ambient and occupational pollution.

Characterization of performance and disinfection resilience of nonwoven filter materials for use in 3D-printed N95 respirators.

The COVID-19 pandemic has caused a high demand for respiratory protection among health care workers in hospitals, especially surgical N95 filtering facepiece respirators (FFRs). To aid in alleviating that demand, a survey of commercially available filter media was conducted to determine whether any could serve as a substitute for an N95 FFR while held in a 3D-printed mask (Stopgap Surgical Face Mask from the NIH 3D Print Exchange). Fourteen filter media types and eight combinations were evaluated for filtration efficiency, breathing resistance (pressure drop), and liquid penetration. Additional testing was conducted to evaluate two filter media disinfection methods in the event that the filters were reused in a hospital setting. Efficiency testing was conducted in accordance with the procedures established for approving an N95 FFR. One apparatus used a filter-holding device and another apparatus employed a manikin head to which the 3D-printed mask could be sealed. The filter media and combinations exhibited collection efficiencies varied between 3.9% and 98.8% when tested with a face velocity comparable to that of a standard N95 FFR at the 85 L min-1 used in the approval procedure. Breathing resistance varied between 10.8 to >637 Pa (1.1 to > 65 mm H2O). When applied to the 3D-printed mask efficiency decreased by an average of 13% and breathing resistance increased 4-fold as a result of the smaller surface area of the filter media when held in that mask compared to that of an N95 FFR. Disinfection by dry heat, even after 25 cycles, did not significantly affect filter efficiency and reduced viral infectivity by > 99.9%. However, 10 cycles of 59% vaporized H2O2 significantly (p < 0.001) reduced filter efficiency of the media tested. Several commercially available filter media were found to be potential replacements for the media used to construct the typical cup-like N95 FFR. However, their use in the 3D-printed mask demonstrated reduced efficiency and increased breathing resistance at 85 L min-1.

Aerosols, airflow, and airspace contamination during laparoscopy.

Laparoscopic surgery has been undermined throughout the COVID-19 pandemic by concerns that it may generate an infectious risk to the operating team through aerosolization of peritoneal particles. There is anyway a need for increased awareness and understanding of the occupational hazard for surgical teams regarding unfiltered escape of pollutants generated by surgical smoke and other microbials. Here, the aerosol-generating nature of this access modality was confirmed through repeatable real-time methodology both qualitatively and quantitively to inform best practice and additional engineering solutions to optimize the operating room environment.

Laparoscopic surgery has been undermined throughout the COVID-19 pandemic by concerns that it may generate an infectious risk to the operating team through aerosolization of peritoneal particles. There is anyway a need for increased awareness and understanding of the occupational hazard for surgical teams regarding unfiltered escape of pollutants generated by surgical smoke and other microbials. Here, the aerosol-generating nature of this access modality was confirmed through repeatable real-time methodology both qualitatively and quantitively to inform best practice and additional engineering solutions to optimize the operating room environment.

How can we minimize the potential risk of viral contamination during laparoscopic procedures for suspected or infected COVID-19 patients?

Several societies have raised the risk of viral transmission of SARS-Cov-2 due to surgical smoke during laparoscopic procedures in infected patients. We propose to discuss this issue and to describe specific measures during laparoscopic procedures and a new homemade closed filtration system for smoke evacuation. Since the outbreak of COVID-19, performing a laparoscopy should meet multi-modal requirements. Surgical smoke evacuation device may be an effective tool in reducing exposure to surgical smoke and aerosols.

Quality Assurance During a Global Pandemic: An Evaluation of Improvised Filter Materials for Healthcare Workers.

OBJECTIVE: The proliferation of improvised masks during the COVID-19 pandemic has raised questions regarding filter effectiveness and safety. We sought to compare the effectiveness of commonly used improvised filter materials against N95 industry standards. METHODS: Six different filter materials commonly used in the community were tested using both single- and multi-layer configurations with the TSI 8130 automated filter tester in accordance with National Institute for Occupational Safety and Health (NIOSH) standards for N95 respirators. RESULTS: Only three of the tested filter material configurations met N95 parameters with regard to filtration efficiency and pressure drop across the filter material-the: True-high-efficiency particulate air (HEPA) filter, four-layer MERV 13 and 14 HVAC filters. CONCLUSIONS: Many proposed filter materials for improvised masks do not meet current industry standards and may pose safety and efficacy concerns. Care should be taken when selecting materials for this critical respirator component, particularly for health care workers or others at high risk for pathogen exposure.

Extent of infectious SARS-CoV-2 aerosolisation as a result of oesophagogastroduodenoscopy or colonoscopy.

BACKGROUND: COVID-19 has caused an unprecedented pandemic and medical emergency that has changed routine care pathways. This article discusses the extent of aerosolisation of severe acute respiratory syndrome coronavirus 2, the virus that causes COVID-19, as a result of oesophagogastroduodenoscopy and colonoscopy. METHODS: PubMed and Google Scholar were searched for relevant publications, using the terms COVID-19 aerosolisation, COVID-19 infection, COVID-19 transmission, COVID-19 pandemic, COVID-19 and endoscopy, Endoscopy for COVID-19 patients. RESULTS: A total of 3745 articles were identified, 26 of which were selected to answer the question of the extent of SARS-CoV-2 aerosolisation during upper and lower gastrointestinal endoscopy. All studies suggested high infectivity from contact and droplet spread. No clinical study has yet reported the viral load in the aerosol and therefore the infective dose has not been accurately determined. However, aerosol-generating procedures are potentially risky and full personal protective equipment should be used. CONCLUSIONS: As it is a highly infectious disease, clinicians treating patients with COVID-19 require effective personal protective equipment. The main routes of infection are direct contact and droplets in the air and on surfaces. Aerosolisation carries a substantial risk of infection, so any aerosol-producing procedure, such as endoscopy, should be performed wearing personal protective equipment and with extra caution to protect the endoscopist, staff and patients from cross-infection via the respiratory system.

Is the ultrasonic scalpel recommended in head and neck surgery during the COVID-19 pandemic? State-of-the-art review.

BACKGROUND: Guidelines for ultrasonic devices use are imperative because infectious aerosols arising from airway procedures were a key etiologic factor in prior coronavirus outbreaks. This manuscript aims to summarize the available recommendations and the most relevant concepts about the use of ultrasonic scalpel during the SARS-CoV-2 pandemic. METHODS: Literature review of manuscripts with patients, animal models, or in vitro studies where the ultrasonic scalpel was used and the plume produced was analyzed in a quantitative and/ or qualitative way. DISCUSSION: Activated devices with tissue produce a biphasic bioaerosol composed (size 68.3-994 nm) of tissue particles, blood, intact and no viable cells, and carcinogenic or irritant hydrocarbons (benzene, ethylbenzene, styrene, toluene, heptene, and methylpropene). CONCLUSION: It is imperative to use an active smoke evacuator, to avoid ultrasonic scalpel use in COVID-19 positive patients and in upper airway surgery, as well as to follow the protection recommendations of the guidelines for management this type of patients.

Endoscopic skull base and transoral surgery during COVID-19 pandemic: Minimizing droplet spread with negative-pressure otolaryngology viral isolation drape.

BACKGROUND: The coronavirus disease (COVID-19) pandemic has raised concern of transmission of infectious organisms through aerosols formation in endonasal and transoral surgery. METHODS: Retrospective review. We introduce the negative-pressure otolaryngology viral isolation drape (NOVID) system to reduce the risk of aerosol. NOVID consists of a plastic drape suspended above the patient's head and surgical field with a smoke evacuator suction placed inside the chamber. RESULTS: Four patients underwent endonasal (4) and endo-oral surgery (1). Fluorescein was applied to the surgical field. Black light examination of fluorescein-treated operative fields revealed minimal contamination distant to the surgical field. In two prolonged cases with high-speed drilling, droplets were identified under the barrier and on the tip of the smoke evacuator. Instruments and cottonoids appeared to be a greater contributor to field contamination. CONCLUSIONS: Negative-pressure aspiration of air under a chamber barrier, which appears to successfully keep aerosol and droplet contamination to a minimum.

Bronchoscopy, laryngoscopy, and esophagoscopy during the COVID-19 pandemic.

BACKGROUND: The United States now has the highest death toll due to COVID-19. Many otolaryngology procedures, including laryngoscopy, bronchoscopy, and esophagoscopy, place otolaryngologists at increased risk of coronavirus transmission due to close contact with respiratory droplets and aerosolization from the procedure. The aim of this study is to provide an overview of guidelines on how to perform these procedures during the coronavirus pandemic. METHODS: Literature review was performed. Articles citing laryngoscopy, bronchoscopy, esophagoscopy use with regard to COVID-19 were included. RESULTS: Laryngoscopy, bronchoscopy, and esophagoscopy are all used in both emergent and elective situations. Understanding the risk stratification of cases and the varied necessity of personal protective equipment is important in protecting patients and health care workers. CONCLUSIONS: Summary guidelines based on the literature available at this time are presented in order to decrease transmission of the virus and protect those involved.

Procedural precautions and personal protective equipment during head and neck instrumentation in the COVID-19 era.

BACKGROUND: Otolaryngologists represent a subset of health care workers uniquely vulnerable to COVID-19 transmission. Given the segmentation of extant guidelines concerning precautions and protective equipment for SARS-CoV2, we aimed to provide consolidated recommendations regarding appropriate personal protective equipment (PPE) in head neck surgery during the COVID-19 era. METHODS: Guidelines published by international and US governing bodies were reviewed in conjunction with published literature concerning COVID-19 transmission risk, testing, and PPE, to compile situation-specific recommendations for head and neck providers managing COVID-19 patients. RESULTS: High-quality data regarding the aerosolization potential of head and neck instrumentation and appropriate PPE during head and neck surgeries are lacking. However, extrapolation of recommendations by governing bodies suggests strongly that head and neck mucosal instrumentation warrants strict adherence to airborne-level precautions. CONCLUSION: We present a series of situation-specific recommendations for PPE use and other procedural precautions for otolaryngology providers to consider in the COVID-19 era.