An operative barrier system for skull base and mastoid surgery: creating a safe operative theatre in the era of COVID-19

Aerosol containment device design considerations and performance evaluation metrics

BACKGROUND

Spurred by the Coronavirus infectious disease 2019 pandemic, aerosol containment devices (ACDs) were developed to capture infectious respiratory aerosols generated by patients at their source. Prior reviews indicated that such devices had low evidence of effectiveness, but did not address how ACDs should be evaluated, how well they should perform, nor have clearly defined performance standards. Towards developing design criteria for ACDs, two questions were posed: 1) What characteristics have guided the design of ACDs? 2) How have these characteristics been evaluated?

METHODS

A scoping review was performed consistent with PRISMA guidelines. Data were extracted with respect to general study information, intended use of the device, device design characteristics and evaluation.

RESULTS

Fifty-four articles were included. Evaluation was most commonly performed with respect to device aerosol containment (n = 31, 61%), with only 5 (9%), 3 (6%) and 8 (15%) formally assessing providing experience, patient experience and procedure impact, respectively. Nearly all of the studies that explored provider experience and procedure impact studied intubation. Few studies provided a priori performance criteria for any evaluation metric, or referenced any external guidelines by which to bench mark performance.

CONCLUSION

With respect to aerosol containment, ACDs should reduce exposure among HCP with the device compared with the absence of the device, and provide ≥90% reduction in respirable aerosols, equivalent in performance to N95 filtering facepiece respirators, if the goal is to reduce reliance on personal protective equipment. The ACD should not increase awkward or uncomfortable postures, or adversely impact biomechanics of the procedure itself as this could have implications for procedure outcomes. A variety of standardized instruments exist to assess the experience of patients and healthcare personnel. Integration of ACDs into routine clinical practice requires rigorous studies of aerosol containment and the user experience.

The effect of air purifiers and curtains on aerosol dispersion and removal in multi-patient hospital rooms

Airborne transmission of disease is of concern in many indoor spaces. Here, aerosol dispersion and removal in an unoccupied 4-bed hospital room were characterized using a transient aerosol tracer experiment for 38 experiments covering 4 configurations of air purifiers and 3 configurations of curtains. NaCl particle (mass mean aerodynamic diameter ~3 μm) concentrations were measured around the room following an aerosol release. Particle transport across the room was 1.5-4 min which overlaps with the characteristic times for significant viral deactivation and gravitational settling of larger particles. Concentrations were close to spatially uniform except very near the source. Curtains resulted in a modest increase in delay and decay times, less so when combined with purifiers. The aerosol decay rate was in most cases higher than expected from the clean air delivery rate, but the reduction in steady-state concentrations resulting from air purifiers was less than suggested by the decay rates. Apparently, a substantial (and configuration-dependent) fraction of the aerosol is removed immediately, and this effect is not captured by the decay rate. Overall, the combination of curtains and purifiers is likely to reduce disease transmission in multi-patient hospital rooms.

COVID-19 and otologic surgery

In this article, we aim to summarize the impacts of COVID-19 on the practice of otologic surgery. Cadaveric studies have indicated COVID-19 viral particles are present in the middle ear mucosa of infected hosts. Otologic procedures can generate significant amounts of droplets due to reliance on high-speed drills. Multiple guidelines have been developed to improve patient and provider safety peri-operatively. Particle dispersion can be mitigated during microscopic mastoidectomy by utilizing barrier drape techniques. The barrier drape may similarly be applied to the surgical exoscope. Endoscopic techniques have theoretical improved safety benefits by minimizing the need for drilling. The discoveries and innovations borne of the COVID-19 pandemic will lay the groundwork for the practice of otology amidst future pandemics.

Otitis Media Practice During the COVID-19 Pandemic

The global coronavirus disease-2019 (COVID-19) pandemic has changed the prevalence and management of many pediatric infectious diseases, including acute otitis media (AOM). Coronaviruses are a group of RNA viruses that cause respiratory tract infections in humans. Before the COVID-19 pandemic, coronavirus serotypes OC43, 229E, HKU1, and NL63 were infrequently detected in middle ear fluid (MEF) specimens and nasopharyngeal aspirates in children with AOM during the 1990s and 2000s and were associated with a mild course of the disease. At times when CoV was detected in OM cases, the overall viral load was relatively low. The new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative pathogen responsible for the eruption of the COVID-19 global pandemic. Following the pandemic declaration in many countries and by the World Health Organization in March 2020, preventive proactive measures were imposed to limit COVID-19. These included social distancing; lockdowns; closure of workplaces; kindergartens and schools; increased hygiene; use of antiseptics and alcohol-based gels; frequent temperature measurements and wearing masks. These measures were not the only ones taken, as hospitals and clinics tried to minimize treating non-urgent medical referrals such as OM, and elective surgical procedures were canceled, such as ventilating tube insertion (VTI). These changes and regulations altered the way OM is practiced during the COVID-19 pandemic. Advents in technology allowed a vast use of telemedicine technologies for OM, however, the accuracy of AOM diagnosis in those encounters was in doubt, and antibiotic prescription rates were still reported to be high. There was an overall decrease in AOM episodes and admissions rates and with high spontaneous resolution rates of MEF in children, and a reduction in VTI surgeries. Despite an initial fear regarding viral shedding during myringotomy, the procedure was shown to be safe. Special draping techniques for otologic surgery were suggested. Other aspects of OM practice included the presentation of adult patients with AOM who tested positive for SARS-2-CoV and its detection in MEF samples in living patients and in the mucosa of the middle ear and mastoid in post-mortem specimens.

Mitigation of Particle Spread During Mastoidectomy: A Systematic Review

Our objective is to analyze the risk of particle spread through mastoidectomy during the COVID-19 pandemic with an aim to assess the tools used to mitigate the spread. A systematic review was conducted using PRISMA guidelines. Our search terms included: MASTOIDECTOMY + COVID-19 or MASTOIDECTOMY + SAR- CoV-2 or MASTOIDECTOMY + CORONAVIRUS. Studies consistent with the inclusion and exclusion criteria were included in the review. Of the 20 articles identified in the initial search, six met the inclusion criteria. The included articles were all experimental studies, with five studies using cadaver subjects and one study using live human subjects. Three studies measured droplet spread and three studies measured aerosolized particle spread. The maximum distance of particle spread ranged from 30 cm to 208 cm. Four studies assessed the use of a barrier system, with two using the OtoTent and two using a barrier drape. Two studies defined the microscope alone as a possible mitigatory tool. One study compared burr type and size to determine the effects on particle spread. During the coronavirus disease 2019 (COVID-19) pandemic, evaluation of tools to mitigate particle spread is imperative for the safety of the surgical team and the healthcare system at large. Barrier drapes, OtoTents and microscopes all have proven to mitigate particle spread; however, further research needs to be performed to compare their efficacy and develop a standard of safety.

[The first year of the SARS-CoV-2 pandemic-impact on otorhinolaryngology]

BACKGROUND

The first year of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has already affected our public health care system to an enormous extent and will continue to do so in the future. Otorhinolaryngologists (ORLs) are suspected to be at high risk of infection, due to the high viral load in the mucosa of the upper airways. The current review evaluates the impact of the pandemic on ORLs' activities and assesses the risk infection.

METHODS

A selective literature research was conducted using relevant English and German terms for ORL, SARS-CoV‑2, risk, and infection at PubMed, medRxiv, and bioRxiv, as well as in the Deutsches Ärzteblatt and on the websites of the Robert Koch Institute and the Johns Hopkins University.

RESULTS

Protection recommendations for ORL include general hygiene measures and wearing KN95 masks for routine professional activities. When in contact with coronavirus disease 2019 (COVID-19) patients, it is recommended to extend the personal protective equipment by eye protection, gloves, cap, and gown. International otorhinolaryngology societies have released guidelines for procedures (e.g., tracheostomy, sinus surgery), propagating personal protection for the surgical team and reduction of aerosols. Testing for SARS-CoV‑2 in patients and medical staff can contribute to reducing the risk of infection. Vaccination would provide some additional protection for ORLs and other health care professionals with increased exposure to aerosols. There is increasing evidence that ORLs are at a high risk of contracting SARS-CoV‑2.

CONCLUSION

Consequent personal protection, frequent testing of patients and health care professionals, and the promised SARS-CoV‑2 vaccinations may provide adequate protection for highly exposed persons.