Assessing the Physiological Relevance of Cough Simulators for Respiratory Droplet Dispersion

Health Care Simulation as a Training Tool for Epidemic Management: A Systematic Review

SUMMARY STATEMENT

The objective of this research was to identify and review studies that have evaluated the impact of simulation-based training on health care professionals during epidemics.All studies in health care simulation-based training published during the last 5 epidemics with a global impact (SARS-CoV, H1N1, MERS, Ebola, SARS-CoV-2; through July 2021) were selected from a systematic search of PUBMED, EMBASE, and key journals.The search strategy identified 274 studies; 148 met the inclusion criteria and were included. Most of the studies were developed in response to SARS-CoV-2 infection (n = 117, 79.1%), used a descriptive approach (n = 54, 36.5%), and were used to train technical skills (n = 82, 55.4%).This review demonstrates a growing interest in publications related to health care simulation and epidemics. Most of the literature is marked by limited study designs and outcome measurements, although there is a trend toward the use of more refined methodologies in the most recent publications. Further research should seek the best evidence-based instructional strategies to design training programs in preparation for future outbreaks.

Quantifying Simulated Contamination Deposition on Healthcare Providers Using Image Analysis

INTRODUCTION

Simulation-based research has played an important role in improving care for communicable diseases. Unfortunately, few studies have attempted to quantify the level of contamination in these simulation activities. We aim to assess the feasibility and provide validity evidence for using integrated density values and area of contamination (AOC) to differentiate various levels of simulated contamination.

METHODS

An increasing number of simulated contamination spots using fluorescent marker were applied on a manikin chest to simulate a contaminated healthcare provider. An ultraviolet light was used to illuminate the manikin to highlight the simulated contamination. Images of increasing contamination levels were captured using a camera with different exposure settings. Image processing software was used to measure 2 outcomes: (1) natural logarithm of integrated density; and (2) AOC. Mixed-effects linear regression models were used to assess the effect of contamination levels and exposure settings on both outcome measures. A standardized "proof-of-concept" exercise was set up to calibrate and formalize the process for human subjects.

RESULTS

A total of 140 images were included in the analyses. Dose-response relationships were observed between contamination levels and both outcome measures. For each increment in the number of contaminated simulation spots (ie, simulated contaminated area increased by 38.5 mm 2 ), on average, log-integrated density increased by 0.009 (95% confidence interval, 0.006-0.012; P < 0.001) and measured AOC increased by 37.8 mm 2 (95% confidence interval, 36.7-38.8 mm 2 ; P < 0.001), which is very close to actual value (38.5 mm 2 ). The "proof-of-concept" demonstration further verified results.

CONCLUSIONS

Integrated density and AOC measured by image processing can differentiate various levels of simulated, fluorescent contamination. The AOC measured highly agrees with the actual value. This method should be optimized and used in the future research to detect simulated contamination deposited on healthcare providers.

Recent advances in respiratory immunization: A focus on COVID-19 vaccines

The development of vaccines has always been an essential task worldwide since vaccines are regarded as powerful weapons in protecting the global population. Although the vast majority of currently authorized human vaccinations are administered intramuscularly or subcutaneously, exploring novel routes of immunization has been a prominent area of study in recent years. This is particularly relevant in the face of pandemic diseases, such as COVID-19, where respiratory immunization offers distinct advantages, such as inducing systemic and mucosal responses to prevent viral infections in both the upper and lower respiratory tracts and also leading to higher patient compliance. However, the development of respiratory vaccines confronts challenges due to the physiological barriers of the respiratory tract, with most of these vaccines still in the research and development stage. In this review, we detail the structure of the respiratory tract and the mechanisms of mucosal immunity, as well as the obstacles to respiratory vaccination. We also examine the considerations necessary in constructing a COVID-19 respiratory vaccine, including the dosage form of the vaccines, potential excipients and mucosal adjuvants, and delivery systems and devices for respiratory vaccines. Finally, we present a comprehensive overview of the COVID-19 respiratory vaccines currently under clinical investigation. We hope this review can provide valuable insights and inspiration for the future development of respiratory vaccinations.

COMPARATIVE ASSESSMENT OF BACTERIAL PERMEABILITY OF A PERSONAL PROTECTIVE RESPIRATORY EQUIPMENT AT DIFFERENT DURATIONS OF ITS CONTINUOUS OPERATION

OBJECTIVE

The aim: To establish the level of antibacterial protection of the studied personal protective respiratory equipment set and its main components and compare antibacterial resistance of the personal protective respiratory equipment set in the presence and absence of filtering components.

PATIENTS AND METHODS

Materials and methods: The proposed methodology for assessing biological protection parameters is based on testing the permeability of personal respiratory protection equipment for bacteria by the method of serial dilutions. Also additional culturing of separate components of the protective set on a separate media is carried out. The experiment was also repeated in the absence of filtering elements and when they were replaced by gauze masks.

RESULTS

Results: The use of a fully equipped pneumatic helmet counteracted the penetration of the bacterial aerosol, which was manifested in the absence of growth on the media. The results obtained with the full configuration, as well as the indicators of the spread of bacteria when removing the filter elements and replacing them with gauze masks, showed that the device creates sufficient positive air pressure inside. The latter becomes a restraining factor that does not allow microorganisms to penetrate through the lower circuit.

CONCLUSION

Conclusions: Increasing the duration of continuous operation of the conceptual model up to 24 hours, increasing the bacterial load on the filters do not lead to a deterioration in the properties of antibacterial protection. Bacterial aerosol did not penetrate into the inner space of pneumatic helmet.

Mitigating the Spread of Covid-19 During Extubation: Assessing the Impact of a Barrier Device

COVID-19 is a novel virus spread via airborne particles. Given the inherent risk to the anesthesia provider, intubation and airway management guidelines have been recently established. Various studies have been published advocating and detailing the results of different intubation devices designed to decrease the number of airborne particles. Currently, little literature exists regarding devices designed to mitigate the spread of COVID-19 airborne particles during extubation. The purpose of this prospective in situ simulated manikin study was to measure the effectiveness of an aerosolized containment device during passive (deep) and forced (simulated coughing) extubation. Airborne particles were measured at the 0.3, 0.5, 1, 2, 5, 10-micron level. Statistically significant decreases were seen with the use of a barrier device during both passive and forced extubation.

Patient-worn endoscopy mask to protect against viral transmission

OBJECTIVES

To design and evaluate patient-worn personal protective equipment (PPE) that allows providers to perform endoscopy while protecting against droplet and airborne disease transmission.

STUDY DESIGN

Single subject study.

METHODS

Mask efficacy was evaluated using a cough simulator that sprays dye visible under ultra-violet light. User-testing was performed on an airway trainer mannequin where each subject performed the endoscopy with and without the mask in random orders. Their time to completion and number of attempts before successful completion were recorded, and each subject was asked to fill out a NASA Task Load Index (TLX) form with respect to their experience.

RESULTS

The mask has a filtration efficiency of 97.31% and eliminated any expelled particles with the cough simulator. Without the mask, a simulated cough is visualized as it progresses away from the cough origin. Subjects who performed trans-nasal endoscopy spent 27.8 ± 8.0 s to visualize the vocal cords for the no mask condition and 28.7 ± 13.6 s for the mask condition (mean ± SD, p > .05). There was no statistically significant difference found in the mental demand, physical demand, temporal demand, performance, effort, and frustration of endoscopy under the no mask and mask conditions (all p > .05).

CONCLUSION

The designed PPE provides an effective barrier for viral droplet and airborne transmission while allowing the ability to perform endoscopy with ease.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Development of a Mannequin for Simulation-Based Trials Involving Respiratory Viral Spread During Respiratory Arrest and Cardiopulmonary Arrest Scenarios

During the coronavirus disease 2019 (COVID-19) pandemic, mannequin models have been developed to mimic viral spread using fluorescent particles. These models use contraptions such as a spray gun or an exploding latex balloon to emanate a sudden acceleration of particles, simulating a "cough" reflex. No models have been developed to mimic passive aerosolization of viral particles during a cardiopulmonary arrest simulation. Our novel approach to aerosolization of simulated viral spread allows for a continuous flow of particles, which allows us to maintain components of high-fidelity team-based simulations. Our simulated model emanated GloGerm (Moab, UT) from the respiratory tract using a continuous nebulization chamber. Uniquely, the construction of our apparatus allowed for the ability to perform full, simulated cardiopulmonary resuscitation scenarios (such as chest compressions, bag-mask ventilation, and endotracheal intubation) on a high-fidelity mannequin while visualizing potential contamination spread at the conclusion of the simulation. Positive feedback from users included the ability to visualize particulate contamination after cardiopulmonary resuscitations in the context of personal protective equipment usage and roles in resuscitation (i.e. physician, respiratory therapist, nurse). Negative criticism towards the simulation included the lack of certain high-fidelity feedback markers of the mannequin (auscultating breath sounds and checking pulses) due to the construction of the particle aerosolization mechanism.

What We Are Learning from COVID-19 for Respiratory Protection: Contemporary and Emerging Issues

Infectious respiratory diseases such as the current COVID-19 have caused public health crises and interfered with social activity. Given the complexity of these novel infectious diseases, their dynamic nature, along with rapid changes in social and occupational environments, technology, and means of interpersonal interaction, respiratory protective devices (RPDs) play a crucial role in controlling infection, particularly for viruses like SARS-CoV-2 that have a high transmission rate, strong viability, multiple infection routes and mechanisms, and emerging new variants that could reduce the efficacy of existing vaccines. Evidence of asymptomatic and pre-symptomatic transmissions further highlights the importance of a universal adoption of RPDs. RPDs have substantially improved over the past 100 years due to advances in technology, materials, and medical knowledge. However, several issues still need to be addressed such as engineering performance, comfort, testing standards, compliance monitoring, and regulations, especially considering the recent emergence of pathogens with novel transmission characteristics. In this review, we summarize existing knowledge and understanding on respiratory infectious diseases and their protection, discuss the emerging issues that influence the resulting protective and comfort performance of the RPDs, and provide insights in the identified knowledge gaps and future directions with diverse perspectives.

The effectiveness of the Safety in Interventional Radiology (SIR) Shield in reducing droplet transmission and its effect on image quality and radiation dose

Objective:

To evaluate the efficacy of a barrier shield in reducing droplet transmission and its effect on image quality and radiation dose in an interventional suite.

Methods:

A human cough droplet visualisation model in a supine position was developed to assess efficacy of barrier shield in reducing environmental contamination. Its effect on image quality (resolution and contrast) was evaluated via image quality test phantom. Changes in the radiation dose to patient post-shield utilisation was measured.

Results:

Use of the shield prevented escape of visible fluorescent cough droplets from the containment area. No subjective change in line-pair resolution was observed. No significant difference in contrast-to-noise ratio was measured. Radiation dosage to patient was increased; this is predominantly attributed to the increased air gap and not the physical properties of the shield.

Conclusion:

Use of the barrier shield provided an effective added layer of personal protection in the interventional radiology theatre for aerosol generating procedures.

Advances in knowledge:

This is the first time a human supine cough droplet visualisation has been developed. While multiple types of barrier shields have been described, this is the first systematic practical evaluation of a barrier shield designed for use in the interventional radiology theatre.

A Novel Cough Simulation Device for Education of Risk Mitigation Techniques During Aerosol-Generating Medical Procedures

The COVID-19 pandemic has drawn attention to aerosol-generating medical procedures (AGMPs) in health care environments as a potential mode of transmission. Many organizations and institutions have published AGMP safety guidelines, and several mention the use of simulation in informing their recommendations; however, current methods used to simulate aerosol generation are heterogenous. Creation of a high-fidelity, easily producible aerosol-generating cough simulator would meet a high-priority educational need across all medical specialties. In this communication, we describe the design, construction, and user study of a novel cough simulator, which demonstrates the utility of simulation in raising AGMP safety awareness for providers of all roles, specialties, and training levels.

KN95 and N95 Respirators Retain Filtration Efficiency despite a Loss of Dipole Charge during Decontamination

N95 decontamination protocols and KN95 respirators have been described as solutions to a lack of personal protective equipment. However, there are a few material science studies that characterize the charge distribution and physical changes accompanying disinfection treatments, particularly heating. Here, we report the filtration efficiency, dipole charge density, and fiber integrity of N95 and KN95 respirators before and after various decontamination methods. We found that the filter layers in N95 and KN95 respirators maintained their fiber integrity without any deformations during disinfection. The filter layers of N95 respirators were 8-fold thicker and had 2-fold higher dipole charge density than that of KN95 respirators. Emergency Use Authorization (EUA)-approved KN95 respirators showed filtration efficiencies as high as N95 respirators. Interestingly, although there was a significant drop in the dipole charge in both respirators during decontamination, there was no remarkable decrease in the filtration efficiencies due to mechanical filtration. Cotton and polyester face masks had a lower filtration efficiency and lower dipole charge. In conclusion, a loss of electrostatic charge does not directly correlate to the decreased performance of either respirator.