key: cord-0995782-vc4wg9hr
authors: Sharma, Dhruv; Campiti, Vincent J.; Ye, Michael J.; Rubel, Kolin E.; Higgins, Thomas S.; Wu, Arthur W.; Shipchandler, Taha Z.; Burgin, Sarah J.; Sim, Michael W.; Illing, Elisa A.; Park, Jae Hong; Ting, Jonathan Y.
title: Aerosol generation during routine rhinologic surgeries and in‐office procedures
date: 2021-01-14
journal: Laryngoscope Investig Otolaryngol
DOI: 10.1002/lio2.520
sha: 7109317dc3c35013509356d5ed1938b939d1b042
doc_id: 995782
cord_uid: vc4wg9hr

OBJECTIVE: Cadaveric simulations have shown endonasal drilling and cautery generate aerosols, which is a significant concern for otolaryngologists during the COVID‐19 era. This study quantifies aerosol generation during routine rhinologic surgeries and in‐office procedures in live patients. METHODS: Aerosols ranging from 0.30 to 10.0 μm were measured in real‐time using an optical particle sizer during surgeries and in‐office procedures. Various mask conditions were tested during rigid nasal endoscopy (RNE) and postoperative debridement (POD). RESULTS: Higher aerosol concentrations (AC) ranging from 2.69 to 10.0 μm were measured during RNE (n = 9) with no mask vs two mask conditions (P = .002 and P = .017). Mean AC (0.30‐10.0 μm) were significantly higher during POD (n = 9) for no mask vs a mask covering the patient's mouth condition (mean difference = 0.16 ± 0.03 particles/cm(3), 95% CI 0.10‐0.22, P < .001). There were no discernible spikes in aerosol levels during endoscopic septoplasty (n = 3). Aerosol spikes were measured in two of three functional endoscopic sinus surgeries (FESS) with microdebrider. Using suction mitigation, there were no discernible spikes during powered drilling in two anterior skull base surgeries (ASBS). CONCLUSION: Use of a surgical mask over the patient's mouth during in‐office procedures or a mask with a slit for an endoscope during RNE significantly diminished aerosol generation. However, whether this reduction in aerosol generation is sufficient to prevent transmission of communicable diseases via aerosols was beyond the scope of this study. There were several spikes in aerosols during FESS and ASBS, though none were associated with endonasal drilling with the use of suction mitigation. LEVEL OF EVIDENCE: 4.

The coronavirus disease 2019 (COVID-19) is caused by a highly infectious novel viral strain, named as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The World Health Organization (WHO) has declared the outbreak a pandemic with over 77 million confirmed cases and nearly 1.7 million deaths globally as of December 24, 2020. 1 Initial research suggests that SARS-CoV-2 is transmitted not only through large respiratory droplets but also through airborne aerosols smaller than 5 μm, which can remain suspended for several hours. 2, 3 Endoscopic endonasal procedures have been of particular concern for Otolaryngologists due to the high viral load in the upper airway of infected patients. 4 A droplet analysis study reported only minimal droplet production during functional endoscopic sinus surgery (FESS) with microdebrider and powered endonasal drilling, which resolved with the use of concurrent suction. 5 However, three cadaveric studies have shown that endonasal techniques, including drilling and cautery, generate significant aerosol concentrations (AC) over baseline levels. [6] [7] [8] As these previous surgical simulations were performed on cadaver heads, it is certainly plausible that the lack of normal physiologic temperature and blood flow, intranasal secretions, and disease conditions such as nasal polyposis influenced aerosol production and mitigation. Recently, Murr et al reported that although there was no significant aerosol generation with diagnostic nasal endoscopy, there were significant increases in AC during cold instrumentation and with the use of suction during sinonasal debridement. 9 The same group also found that significant increases in AC were attributed to the endonasal use of a microdebrider and drill at the position of the surgeon during endonasal surgery on live patients in the operating room. 10 The present study was designed to further contribute to our knowledge base by quantifying the concentration of generated aerosols during routine rhinologic procedures in clinic with and without mask conditions and surgeries in the operating room (OR) on alive patients using a real-time aerosol measuring instrument. 

Prior to each sampling, background aerosol levels were measured once every second for 1 minute, resulting in a total of 60 samples.

The OPS 3330's inlet port was positioned 30 cm from the midline columella on the patient's left side. Aerosol levels during each rigid nasal endoscopy (n = 9) and post-operative sinus debridement (n = 6) were measured once every second for the entire duration of the respective procedure. For rigid nasal endoscopy, the patient was asked to either (a) completely remove their surgical mask for the procedure (n = 3;

denoted "no mask"), (b) wear a standard hospital-issued surgical mask and only lower the mask to uncover the nares directly prior to beginning the procedure (n = 3; denoted "mask"), or (c) wear a valved endoscopy of the nose and throat (VENT) mask 6 for the duration of the procedure (n = 3; denoted "VENT"). For each postoperative sinus debridement, the patient was asked to either (a) completely remove their surgical mask for the procedure (n = 3; denoted "no mask"), or (b) wear a standard hospital-issued surgical mask and only uncover the nares directly prior to beginning the procedure (n = 3; denoted "mask"). assistant. Spikes were defined as sustained elevations in AC, which were greater than two SDs above baseline for at least 1 minute. There was no statistically significant difference in the 0.30 to 0.90 μm range aerosols, but statistically significant differences were present for particles ≥ 0.90 μm ( Table 2 ). Table 3 . There were no discernible spikes in aerosols during the cases. Table 4 . There were no discernible spikes in aerosols during high-speed, powered, endonasal drilling in either procedure.

As a gradual increase in clinical activity and return to performing elective surgeries is being undertaken throughout the United States, many questions remain in regards to performing these surgeries while avoiding or minimizing undue risk to providers and patients. Of particular concern is aerosol-generating procedures, as the airborne particles generated by COVID-19 patients are a suspected transmission vector for the virus. 11 Rhinologic procedures may warrant special concern, as the nasal cavity has been shown to harbor high viral load in infected patients. 4 pandemic. The exact infectious potential of these particles and a definitive concentration of aerosol exposure capable of transmission between individuals is unknown, so any realistic intervention capable of mitigating risk, such as utilizing a mask to cover the mouth during in-office procedures, should be utilized as appropriate.

Interestingly, postoperative debridement of the sinonasal cavities resulted in significantly higher aerosol levels in patients not wearing a mask compared to patients wearing one covering their mouth, specifically in the 0.90 to 10.0 μm range. As the VENT mask only has a single slit for a nasal endoscope, it was deemed not to be a viable option for this in-office procedure which requires two instruments in the nasal cavity at a time. It is also worth noting that no patients sneezed during any of the in-office procedures performed for this study. Thus, there could be a higher risk of aerosol generation with patients more sensitive to the procedures. While a recent study also utilizing an optical particle sizer reported increases in aerosols during post-operative sinonasal debridement, 9 this study is the first to investigate and demonstrate a difference in aerosol exposure with a mask serving as a barrier to the oral cavity.

During FESS, mean ACs were consistently elevated over mean baseline aerosol levels in the three cases during which the microdebrider was utilized as the primary dissection tool. FESS was also performed with entirely non-powered instrumentation to determine the risks associated with microdebrider dissection, and the mean 0.30 to 10 μm aerosol concentration was significantly higher during cold FESS when compared to microdebrider FESS. This defies the expectation that powered instrumentation should produce greater aerosols.

One possible explanation for this is that the suction from the microdebrider was able to mitigate aerosolization, whereas cold, non- presence of these small particles is of particular concern because they are more likely to penetrate an N95 mask. 12 A recent study also investigating aerosol exposure in the operating room during endoscopic sinonasal surgery reported increases in aerosols associated with the microdebrider and drill, 10 field. This study was performed in operating rooms of a single health system. Other operating rooms with different air circulation patterns, air change rates, or room pressure may change the behavior of these aerosols. Due to these comparative limitations and the previously published work based on cadaveric simulations, we recommend these data be used to complement rather than discount previously published findings.

Use of a surgical mask over the patient's mouth during in-office procedures or a VENT mask during RNE diminished aerosol generation.

However, whether this reduction in aerosol generation is sufficient to prevent transmission of communicable diseases via aerosols was beyond the scope of this study. In the operating room, there were several spikes in aerosol levels during microdebrider FESS, which were associated with the use of non-powered instrumentation, sphenoid sinus irrigation, repositioning of the patient's head, and removal of the drapes following completion of the procedure. There were also several spikes during ASBS, which were associated with the use of dural sealant spray, needle tip electrocautery, and coblator. There were no spikes in aerosol levels during endonasal drilling with the use of suction mitigation.

Coronavirus disease 2019 (COVID-19) Dashboard

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Airborne aerosol generation during endonasal procedures in the era of COVID-19: risks and recommendations

Suction mitigation of airborne particulate generated during sinonasal drilling and cautery

Mitigation of aerosols generated during rhinologic surgery: a pandemic-era cadaveric simulation. Otolaryngology-Head Neck Surg. 2020;1-10

Quantification of aerosol concentrations during endonasal instrumentation in the clinic setting. Laryngoscope

Quantification of aerosol concentrations during endoscopic sinonasal surgery in the operating room

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Aerosol generation during routine rhinologic surgeries and inoffice procedures

The authors have no conflict of interest to disclose.

https://orcid.org/0000-0001-8107-9520