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In dentistry, disinfection with antimicrobials is employed under different conditions and at different time points. During the COVID-19 pandemic, the use of disinfectant dental sprays was proposed, among other measures, to help prevent the transmission of infections during dental procedures that require highly effective antiseptics at particularly short contact times. The study aimed to evaluate the efficacy of electrolyzed saline (EOS) compared with other antiseptics in terms of the spread of enveloped and nonenveloped viruses by ultrasonic scaler (USS)–generated dental spray. Suspension tests were performed to evaluate the antiviral efficacy of EOS against herpes simplex virus 1 (HSV-1) and human adenovirus (HAdV), which served as models for enveloped and nonenveloped viruses, respectively. EOS, mostly composed of hypochlorous acid (HOCl), reduced the amount of both virus types in the presence or absence of artificial saliva by > 4 log10 50% tissue culture infectious dose (P < 0.001). In addition, the mechanism of virucidal effect was investigated using transmission electron microscopy. Following this assessment, a virus-laden dental spray transmission model was used to simulate virus-infected patients undergoing dental procedures with USS. Attenuation was achieved by substituting the USS coolant with one of the effective, pretested antiseptics. Due to safety concerns, nonhuman viral pathogens—equine arteritis virus (EAV) and feline calicivirus (FCV)—served as enveloped and nonenveloped virus models, respectively. Viral infection was evaluated by direct droplet/aerosol infection of RK-13 or CRFK cells. In addition, the biocompatibility of the antiseptics was tested with exposure to human oral keratinocytes. EOS demonstrated strong virucidal activity against both enveloped and nonenveloped viruses and was able to absolutely prevent airborne transmission of EAV and FCV through dental spray in the splatter and droplet/aerosol samples. The study emphasized that EOS, a chlorine-based antiseptic, is a promising, reasonably safe, broad-spectrum agent for preventing dental spray–mediated viral transmission. [ABSTRACT FROM AUTHOR]

Background: Conflicting guidance exists regarding the characterization of nebulization as an aerosol-generating procedure and subsequent risk of transmission of SARS-CoV-2 to healthcare workers. Aim/Objective: This study sought to address whether SARS-CoV-2 viral load distribution was impacted by bronchodilator delivery via nebulizer versus metered-dose inhaler (MDI). Methods: Adults infected with COVID-19 were enrolled and received a single dose of albuterol sulfate nebulized solution (2.5 mg/3 mL via breath-actuated nebulizer with filtered mouthpiece) or albuterol sulfate hydrofluoroalkane inhalation aerosol (90 µg/actuation; two puffs via MDI with spacer) in a randomized crossover sequence. Air and surfaces were sampled at predefined locations within patients' hospital rooms to assess SARS-CoV-2 dispersion over three periods (baseline, MDI, and nebulizer). Findings/Results: Eleven patients received crossover therapy. Six patients had detectable SARS-CoV-2 RNA during one treatment period (n = 3 each for MDI and nebulizer) and one during both treatment periods. No viral RNA was found in the rooms of four (36.4%) patients. Overall, few environmental samples (17/397; 4.3%) contained detectable viral RNA, with no meaningful differences in positivity rate across periods; RNA genome copy numbers were low in positive samples. No correlation between dispersion and patient clinical status or environmental parameters was observed. Discussion: In this first prospective trial evaluating viral load distribution following use of nebulizer versus MDI in hospitalized patients with COVID-19, low environmental contamination was found regardless of administration method. Findings support the use of either device when needed to treat patients with COVID-19. [ABSTRACT FROM AUTHOR]

Despite current guidelines for tuberculosis (TB) control in health care settings, which focused on smear-positive cases, prevention of nosocomial TB transmission continues to be a challenge. Here, we report the results of the first hospital-wide prospective study applying interferon-gamma release assay to investigate the role of smear-negative, culture-positive index cases in nosocomial TB transmission. We prospectively identified cases of culture-confirmed smear-negative pulmonary TB receiving aerosol-generating procedures (AGPs) and cases of culture-confirmed smear-positive pulmonary TB admitted at a medical center. Nosocomial transmission was evaluated by screening their close contacts for latent TB infection (LTBI) using an interferon-gamma release assay. A total of 93 smear-negative index receiving AGP and 122 smear-positive index were enrolled. Among them, 13 (14.0%) and 43 (35.2%) index cases, respectively, had secondary cases of LTBI (P <.001). Sputum smear negativity (adjusted odds ratio: 0.20 [0.08-0.48]) and AGP (sputum suction; adjusted odds ratio: 3.48 [1.34-9.05]) are independent factors of transmission. A similar proportion in the close contacts of the 2 index groups had LTBI (17 [15.3%] and 63 [16.0%], respectively), and the former index group contributed to 21.3% of the nosocomial transmission. Smear-negative, culture-positive index cases receiving AGPs could be as infectious as smear-positive index cases. Hospital TB control policy should also focus on the former group. • The role of smear-negative index cases in nosocomial transmission remains unknown. • Smear-negative cases receiving AGPs could be as infectious as smear-positive cases. • Smear-negative cases may be responsible for 21.3% nosocomial TB transmissions. • Ongoing physician education to optimize the utilization of TB-NAAT is imperative. • Hospital TB control should also focus on smear-negative index receiving AGPs. [ABSTRACT FROM AUTHOR]

Nebulizers are used commonly for inhaled drug delivery. Because they deliver medication through aerosol generation, clarification is needed on what constitutes safe aerosol delivery in infectious respiratory disease settings. The COVID-19 pandemic highlighted the importance of understanding the safety and potential risks of aerosol-generating procedures. However, evidence supporting the increased risk of disease transmission with nebulized treatments is inconclusive, and inconsistent guidelines and differing opinions have left uncertainty regarding their use. Many clinicians opt for alternative devices, but this practice could impact outcomes negatively, especially for patients who may not derive full treatment benefit from handheld inhalers. Therefore, it is prudent to develop strategies that can be used during nebulized treatment to minimize the emission of fugitive aerosols, these comprising bioaerosols exhaled by infected individuals and medical aerosols generated by the device that also may be contaminated. This is particularly relevant for patient care in the context of a highly transmissible virus. How can potential risks of infections during nebulization be mitigated? The COPD Foundation Nebulizer Consortium (CNC) was formed in 2020 to address uncertainties surrounding administration of nebulized medication. The CNC is an international, multidisciplinary collaboration of patient advocates, pulmonary physicians, critical care physicians, respiratory therapists, clinical scientists, and pharmacists from research centers, medical centers, professional societies, industry, and government agencies. The CNC developed this expert guidance to inform the safe use of nebulized therapies for patients and providers and to answer key questions surrounding medication delivery with nebulizers during pandemics or when exposure to common respiratory pathogens is anticipated. CNC members reviewed literature and guidelines regarding nebulization and developed two sets of guidance statements: one for the health care setting and one for the home environment. Future studies need to explore the risk of disease transmission with fugitive aerosols associated with different nebulizer types in real patient care situations and to evaluate the effectiveness of mitigation strategies. [ABSTRACT FROM AUTHOR]

Abstract Background The COVID-19 pandemic led to concerns about the potential airborne transmission of the virus during dental procedures, but evidence of actual transmission in clinical settings was lacking. This study aimed to observe the behavior of dental sprays generated from dental rotary handpieces and to evaluate the effectiveness of high-volume evacuators (HVEs) using laser light sheets and water-sensitive papers. Methods A dental manikin and jaw model were mounted in a dental treatment unit. Mock cutting procedures were performed on an artificial tooth on the maxillary left central incisor using an air turbine, a contra-angle electric micromotor (EM), and a 1:5 speed-up contra-angle EM (×5EM). Intraoral vacuum and extraoral vacuum (EOV) were used to verify the effectiveness of the HVEs. The dynamics and dispersal range of the dental sprays were visualized using a laser light sheet. In addition, environmental surface pollution was monitored three-dimensionally using water-sensitive papers. Results Although the HVEs were effective in both the tests, the use of EOV alone increased vertical dispersal and pollution. Conclusions The use of various types of HVEs to reduce the exposure of operators and assistants to dental sprays when using dental rotary cutting instruments is beneficial. The study findings will be helpful in the event of a future pandemic caused by an emerging or re-emerging infectious disease.

Summary: It is unclear if cardiopulmonary resuscitation is an aerosol‐generating procedure and whether this poses a risk of airborne disease transmission to healthcare workers and bystanders. Use of airborne transmission precautions during cardiopulmonary resuscitation may confer rescuer protection but risks patient harm due to delays in commencing treatment. To quantify the risk of respiratory aerosol generation during cardiopulmonary resuscitation in humans, we conducted an aerosol monitoring study during out‐of‐hospital cardiac arrests. Exhaled aerosol was recorded using an optical particle sizer spectrometer connected to the breathing system. Aerosol produced during resuscitation was compared with that produced by control participants under general anaesthesia ventilated with an equivalent respiratory pattern to cardiopulmonary resuscitation. A porcine cardiac arrest model was used to determine the independent contributions of ventilatory breaths, chest compressions and external cardiac defibrillation to aerosol generation. Time‐series analysis of participants with cardiac arrest (n = 18) demonstrated a repeating waveform of respiratory aerosol that mapped to specific components of resuscitation. Very high peak aerosol concentrations were generated during ventilation of participants with cardiac arrest with median (IQR [range]) 17,926 (5546–59,209 [1523–242,648]) particles.l‐1, which were 24‐fold greater than in control participants under general anaesthesia (744 (309–2106 [23–9099]) particles.l‐1, p < 0.001, n = 16). A substantial rise in aerosol also occurred with cardiac defibrillation and chest compressions. In a complimentary porcine model of cardiac arrest, aerosol recordings showed a strikingly similar profile to the human data. Time‐averaged aerosol concentrations during ventilation were approximately 270‐fold higher than before cardiac arrest (19,410 (2307–41,017 [104–136,025]) vs. 72 (41–136 [23–268]) particles.l‐1, p = 0.008). The porcine model also confirmed that both defibrillation and chest compressions generate high concentrations of aerosol independent of, but synergistic with, ventilation. In conclusion, multiple components of cardiopulmonary resuscitation generate high concentrations of respiratory aerosol. We recommend that airborne transmission precautions are warranted in the setting of high‐risk pathogens, until the airway is secured with an airway device and breathing system with a filter. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic led to concerns about the potential airborne transmission of the virus during dental procedures, but evidence of actual transmission in clinical settings was lacking. This study aimed to observe the behavior of dental sprays generated from dental rotary handpieces and to evaluate the effectiveness of high-volume evacuators (HVEs) using laser light sheets and water-sensitive papers. Methods: A dental manikin and jaw model were mounted in a dental treatment unit. Mock cutting procedures were performed on an artificial tooth on the maxillary left central incisor using an air turbine, a contra-angle electric micromotor (EM), and a 1:5 speed-up contra-angle EM (×5EM). Intraoral vacuum and extraoral vacuum (EOV) were used to verify the effectiveness of the HVEs. The dynamics and dispersal range of the dental sprays were visualized using a laser light sheet. In addition, environmental surface pollution was monitored three-dimensionally using water-sensitive papers. Results: Although the HVEs were effective in both the tests, the use of EOV alone increased vertical dispersal and pollution. Conclusions: The use of various types of HVEs to reduce the exposure of operators and assistants to dental sprays when using dental rotary cutting instruments is beneficial. The study findings will be helpful in the event of a future pandemic caused by an emerging or re-emerging infectious disease. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to test the plausibility of using the ΦX174 bacteriophage as a tracer of viral aerosols spreading in a dental aerosol-generating procedure (AGP) model. Methods: ΦX174 bacteriophage (~ 108 plaque-forming units (PFU)/mL) was added into instrument irrigation reservoirs and aerosolized during class-IV cavity preparations followed by composite fillings on natural upper-anterior teeth (n = 3) in a phantom head. Droplets/aerosols were sampled through a passive approach that consisted of Escherichia coli strain C600 cultures immersed in a LB top agar layer in Petri dishes (PDs) in a double-layer technique. In addition, an active approach consisted of E coli C600 on PDs sets mounted in a six-stage cascade Andersen impactor (AI) (simulating human inhalation). The AI was located at 30 cm from the mannequin during AGP and afterwards at 1.5 m. After collection PDs were incubated overnight (18 h at 37 °C) and bacterial lysis was quantified. Results: The passive approach disclosed PFUs mainly concentrated over the dental practitioner, on the mannequin's chest and shoulder and up to 90 cm apart, facing the opposite side of the AGP's source (around the spittoon). The maximum aerosol spreading distance was 1.5 m in front of the mannequin's mouth. The active approach disclosed collection of PFUs corresponding to stages (and aerodynamic diameters) 5 (1.1–2.1 µm) and 6 (0.65–1.1 µm), mimicking access to the lower respiratory airways. Conclusion: The ΦX174 bacteriophage can be used as a traceable viral surrogate in simulated studies contributing to understand dental bioaerosol's behavior, its spreading, and its potential threat for upper and lower respiratory tract. Clinical relevance: The probability to find infectious virus during AGPs is high. This suggests the need to continue characterizing the spreading viral agents in different clinical settings through combination of passive and active approaches. In addition, subsequent identification and implementation of virus-related mitigation strategies is relevant to avoid occupational virus infections. [ABSTRACT FROM AUTHOR]

Objective: Airborne aerosol transmission, an established mechanism of SARS‐CoV‐2 spread, has been successfully mitigated in the health care setting through the adoption of universal masking. Upper airway endoscopy, however, requires direct access to the face, thereby potentially exposing the clinic environment to infectious particles. This study quantifies aerosol production during rigid nasal endoscopy (RNE) and RNE with debridement (RNED) as compared with intubation, a posited gold standard aerosol‐generating procedure. Study Design: Prospective cross‐sectional study. Setting: Subspecialty single‐center clinic and surgical study. Method: Three aerosol detectors (NANOSCAN‐3910, OPS‐3330, and APS‐3321) with a particle size sensitivity of 10 to 20,000 nm were utilized to detect particulate production during the clinical care of 209 patients undergoing RNE/RNED and 25 patients undergoing intubation. Results: RNE and RNED produced statistically significant particles over baseline in 29.3% and 51.0% of subjects (P =.003‐.049 and.002‐.047, respectively). Intubation produced statistically significant particles in 31.2% (P =.001‐.015). The mean ± SD particle diameter in all tests was 69.9 ± 10.5 nm with 99.7% <300 nm. There were no statistical differences in particle production among RNE, RNED, and intubation. The presence of concomitant cough, sneeze, or prolonged speech similarly did not significantly affect particle production during any procedure. Conclusions: Instrumentation of nasal airway produces airborne aerosols to a similar degree of those seen during intubation, independent of reactive patient behaviors such as cough or sneeze. These data suggest that an improved understanding is necessary of both the definition of an aerosol‐generating procedure and the functional consequences of procedural aerosol generation in clinical settings. [ABSTRACT FROM AUTHOR]

Background and Aims: Esophagogastroduodenoscopy (EGD) has been identified as an aerosol‐generating procedure (AGP) during the COVID‐19 pandemic. The risk of AGP and benefits of utilizing protective measures have never been fully studied. Methods: A randomized control, open‐label study in patients scheduled for diagnostic EGD between September and December 2021 was conducted. Patients were randomly assigned to either head box group or without head box group (control group). Particles were measured with six‐size particle counters at the nurse anesthetist and endoscopist position. Primary composite outcomes were the mean difference of aerosol particle levels during and before EGD at the nurse anesthetist face position and at the endoscopist face position. Secondary outcomes were factors increasing aerosol particle levels and safety of the head box. Results: From 196 enrolled patients, 190 were analyzed. Baseline characteristics were not different between the two groups. The mean distance between endoscopist face and patient mouth was 67.2 ± 4.9 cm. The mean differences of 0.3‐, 0.5‐, and 1.0‐μm particles during the procedure and at baseline before the procedure at nurse anesthetist position and the mean differences of 0.3‐μm particles at the endoscopist position was found to have decreased in the head box group and increased in the control group (P < 0.001, 0.001, 0.014, and P < 0.001, respectively). Cough, burping, and body movement increased aerosol particles. No additional adverse events were observed in the head box group. Conclusions: EGD with the head box is safe and can reduce significant aerosolization to endoscopy personnel including nurse anesthetists and endoscopists. [ABSTRACT FROM AUTHOR]

COVID-19 also known as severe acute respiratory syndrome coronavirus 2 is the result of a highly transmissible coronavirus which can result in severe infection of the respiratory tract. The global pandemic which began in early 2020 has created a number of challenges for the medical community to contain the rate of transmission, especially to health care workers. A minority of the infected population will progress toward severe respiratory distress ultimately requiring mechanical ventilator assistance. Although preliminary data suggest a poor prognosis for those requiring ventilation support, there is a subgroup who will eventually be weaned off. As the pandemic evolves, this cohort of infected, chronically intubated and ventilated individuals will become more prevalent and may require tracheostomy to aid in recovery. Unfortunately, tracheostomy is an aerosol-generating procedure which poses high risks to all members within the operating room, as described by previous authors. There is an urgent need to explore and develop methods to maximize the safety of tracheostomy and other aerosol-generating procedures in order to reduce intraoperative transmission. In the present article, we present a modified technique for negative pressure enclosure in patients with COVID-19 who underwent tracheostomy. [ABSTRACT FROM AUTHOR]

Objectives: The COVID‐19 pandemic has raised concerns on whether colonoscopies (CS) carry a transmission risk. The aim was to determine whether CS are aerosol‐generating procedures. Methods: This was a prospective observational trial including all patients undergoing CS at the Prince of Wales Hospital from 1 June to 31 July 2020. Three particle counters were placed 10 cm from each patient's anus and near the mouth of endoscopists and nurses. The particle counter recorded the number of particles of size 0.3, 0.5, 0.7, 1, 5, and 10 μm. Patient demographics, seniority of endoscopists, use of CO2 and water immersion technique, and air particle count (particles/cubic foot, dCF) were recorded. Multilevel modeling was used to test all the hypotheses with a post‐hoc analysis. Results: A total of 117 patients were recruited. During CS, the level of 5 μm and 10 μm were significantly higher than the baseline period (P = 0.002). Procedures performed by trainees had a higher level of aerosols when compared to specialists (0.3 μm, P < 0.001; 0.5 μm and 0.7 μm, P < 0.001). The use of CO2 and water immersion techniques had significantly lower aerosols generated when compared to air (CO2: 0.3, 0.5, and 0.7 μm: P < 0.001; water immersion: 0.3 μm: P = 0.048; 0.7 μm: P = 0.03). There were no significant increases in any particle sizes during the procedure at the endoscopists' and nurses' mouth. However, 8/117 (6.83%) particle count tracings showed a simultaneous surge of all particle sizes at the patient's anus and endoscopists' and nurses' level during rectal extubation. Conclusion: Colonoscopy generates droplet nuclei especially during rectal extubation. The use of CO2 and water immersion techniques may mitigate these risks. [ABSTRACT FROM AUTHOR]

Introduction: Coronavirus disease 2019 (COVID-19) is a highly contagious disease transmitted by contact, droplets, and aerosols. Front line health-care workers (HCWs), particularly emergency physicians and acute care providers, are vulnerable to being exposed while treating their sick patients. Despite appropriate personal protective equipment use, HCW gets infected, suggesting the need for multiple layers of protection such as barrier devices. Methods: We aimed to determine the effectiveness of our novel “Resuscitation Cover All”(RCA) in reducing the exposure of HCW to simulated respiratory particles and its feasibility during cardio pulmonary resuscitation (CPR). This was a pilot simulation-based study. Five CPR simulation sessions were performed in Standard and RCA protocols, individually. Exposures through contact, droplets, and aerosols were simulated using a standardized volume of liquid detergent. Under Wood's lamp illumination, exposures of participants were compared between the protocols. Rate and depth of chest compressions, time taken to intubate, interruptions in CPR, and first-pass success were analyzed. Results: Overall mean exposure in standard protocol was 4950.4 ± 1461.6 (95%confidence interval [CI]:3135.7–6765.2) sq.pixels and RCA protocol was 2203.6 ± 1499.0 (95%CI: 342.4–4064.9) sq.pixels (P = 0.019). In standard, chest compressor had the highest exposure of 3066.6 ± 1419.2 (95%CI: 2051.3–4081.9) sq.pixels followed by defibrillator assistant 1166.4 ± 767.4 (95%CI: 617.4–1715.4) sq.pixels. Chest compressor of RCA had reduced exposure compared to that of standard (P < 0.001). Hands were the most frequently exposed body part. Airway manager of RCA had no exposure over head and neck in any session. No significant difference in CPR performance metrics was observed. Conclusion: This pilot simulation-based study shows that the novel RCA device could minimize the exposure of HCW to simulated respiratory particles during CPR. Also, it might not alter the high-quality CPR performance metrics. We need more real-life evidence.

Oral microbes are dispersed during dental treatment and reduction methods have been proposed, but dental unit waterline (DUWL) disinfectants have received little attention; specifically, the effect on viruses has not been studied. This study aims to 1) investigate the effect of DUWL disinfectants on viral dispersion in dental bioaerosols and 2) establish a dual-tracer system using live bacteriophage and fluorescein supported by optical particle measurement. Bacteriophage MS2 was used as a viral tracer and fluorescein as a fluorescent tracer. Validation experiments were conducted to exclude interference of one tracer with the other or of DUWL disinfectants on detection methods. Simulated "saliva" containing the tracers was infused into the mouth of a dental mannequin during 10-min dental procedures with an air turbine handpiece (n = 3 replicates). Aerosols and droplets were sampled in an enclosed dental operatory using air samplers and settlement onto sterile filter papers. Bacteriophage was quantified using plaque assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR). Fluorescein was quantified fluorometrically. The effect of DUWL disinfectants on total aerosol concentration was assessed in separate experiments using an optical particle counter. DUWL disinfectants reduced bacteriophage viability, and interference between tracers was not observed. In simulated clinical procedures, the disinfectant ICX reduced bacteriophage detection substantially (P < 0.001; 2-way analysis of variance). MS2 RNA was detected in all experimental samples but not negative controls. Samples positive on RT-qPCR but not plaque assays may indicate that virions at distant sites are nonviable. Fluorescein tracer showed good agreement with the bacteriophage tracer. DUWL disinfectants designed for continuous presence in irrigants reduce the dispersion of viable virus in dental bioaerosols during simulated procedures. Their use may therefore be important for routine infection control and as a mitigation factor during infectious disease outbreaks. Future studies should explore this using a range of viruses and other microbes. [ABSTRACT FROM AUTHOR]

Abstract Objective The risk of SARS‐CoV‐2 transmission to healthcare workers through airborne aerosolization during otologic surgery has not been characterized. The objective of this study was to describe and quantify the aerosol generation during common otologic procedures in both cadaveric surgical simulation and live patient surgery. Methods The number concentrations of generated aerosols in the particle size range of 0.30 to 10.0 μm were quantified using an optical particle sizer during both a cadaveric simulation of routine otologic procedures as well as cochlear implant surgery on live patients in the operating room. Results In the cadaveric simulation, temporalis fascia graft harvest using cold techniques (without electrocautery) (n = 4) did not generate aerosols above baseline concentrations. Tympanoplasty (n = 3) and mastoidectomy (n = 3) both produced statistically significant increases in concentrations of aerosols (P

Abstract 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/cm3, 95% CI 0.10‐0.22, P

The outbreak of novel coronavirus disease (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to a global pandemic of unprecedented proportions. Management of patients infected with COVID-19 has led to a great risk of hospital-based transmission of infection to health-care professionals (HCPs). The HCPs at various levels in a multispecialty health-care setup are at risk of contracting the virus. Those who are involved with performing or assisting in aerosol-generating procedures (AGPs) have a potentially higher risk of developing the infection. The AGPs involve a wide range of procedures such as pulmonary function testing, high-flow oxygen administration, endotracheal intubation, nebulization, application of ventilators, weaning and extubation, bronchoscopy, tracheostomy, and cardiopulmonary resuscitation. Hence, understanding the overall nature of the disease is of vital importance to develop preventive strategies to reduce transmission of the virus through aerosols. This review article intends to elucidate the port of entry associated with SARS-CoV-2 infection and its spread through the AGPs. We also intend to focus on methods to prevent aerosol-related transmission of infection to HCPs by illustrating clinically practiced evidence-based protocol followed in our multispecialty health-care setup.

Dental procedures produce aerosols that may remain suspended and travel significant distances from the source. Dental aerosols and droplets contain oral microbes, and there is potential for infectious disease transmission and major disruption to dental services during infectious disease outbreaks. One method to control hazardous aerosols often used in industry is local exhaust ventilation (LEV). The aim of this study was to investigate the effect of LEV on aerosols and droplets produced during dental procedures. Experiments were conducted on dental mannequins in an 825.4-m3 open-plan clinic and a 49.3-m3 single surgery. Ten-minute crown preparations were performed with an air-turbine handpiece in the open-plan clinic and 10-min full-mouth ultrasonic scaling in the single surgery. Fluorescein was added to instrument irrigation reservoirs as a tracer. In both settings, optical particle counters (OPCs) were used to measure aerosol particles between 0.3 and 10.0 µm, and liquid cyclone air samplers were used to capture aerosolized fluorescein tracer. In addition, in the open-plan setting, fluorescein tracer was captured by passive settling onto filter papers in the environment. Tracer was quantified fluorometrically. An LEV device with high-efficiency particulate air filtration and a flow rate of 5,000 L/min was used. LEV reduced aerosol production from the air-turbine handpiece by 90% within 0.5 m, and this was 99% for the ultrasonic scaler. OPC particle counts were substantially reduced for both procedures and air-turbine settled droplet detection reduced by 95% within 0.5 m. The effect of LEV was substantially greater than suction alone for the air-turbine and was similar to the effect of suction for the ultrasonic scaler. LEV reduces aerosol and droplet contamination from dental procedures by at least 90% in the breathing zone of the operator, and it is therefore a valuable tool to reduce the dispersion of dental aerosols. [ABSTRACT FROM AUTHOR]

Summary: Background: Physicians have had to perform numerous extubation procedures during the prolonged coronavirus disease 2019 (COVID 19) pandemic. Future pandemics caused by unknown pathogen may also present a risk of exposure to infectious droplets and aerosols. Aim: This study evaluated the ability of a newly developed aerosol barrier, “Extubation-Aerosol (EA)-Shield” to provide maximum protection from aerosol exposure during extubation via an aerosolised particle count and high-quality visualisation assessments. Methods: We employed a cough model having parameters similar to humans and used micron oil aerosol as well as titanium dioxide as aerosol tracers. Aerosol barrier techniques employing a face mask (group M) and EA-Shield (group H) were compared. Findings: The primary outcome was the difference in the number of particles contacting the physician's face before and after extubation. The maximum distances of aerosol dispersal after extubation were measured as the secondary outcomes. All aerosolised particles of the two tracers were significantly smaller in group H than in group M (p < 0.05). In addition, the sagittal and axial maximum distances and sagittal areas of aerosol dispersal for 3, 5, and 10 s after extubation were significantly smaller in group H than in group M (p < 0.05). Conclusion: This model indicates that EA-Shield could be highly effective in reducing aerosol exposure during extubation. Therefore, we recommend using it as an aerosol barrier when an infectious aerosol risk is suspected.

Manual facemask ventilation, a core component of elective and emergency airway management, is classified as an aerosol-generating procedure. This designation is based on one epidemiological study suggesting an association between facemask ventilation and transmission during the SARS-CoV-1 outbreak in 2003. There is no direct evidence to indicate whether facemask ventilation is a high-risk procedure for aerosol generation. We conducted aerosol monitoring during routine facemask ventilation and facemask ventilation with an intentionally generated leak in anaesthetised patients. Recordings were made in ultraclean operating theatres and compared against the aerosol generated by tidal breathing and cough manoeuvres. Respiratory aerosol from tidal breathing in 11 patients was reliably detected above the very low background particle concentrations with median [IQR (range)] particle counts of 191 (77-486 [4-1313]) and 2 (1-5 [0-13]) particles.l-1 , respectively, p = 0.002. The median (IQR [range]) aerosol concentration detected during facemask ventilation without a leak (3 (0-9 [0-43]) particles.l-1 ) and with an intentional leak (11 (7-26 [1-62]) particles.l-1 ) was 64-fold (p = 0.001) and 17-fold (p = 0.002) lower than that of tidal breathing, respectively. Median (IQR [range]) peak particle concentration during facemask ventilation both without a leak (60 (0-60 [0-120]) particles.l-1 ) and with a leak (120 (60-180 [60-480]) particles.l-1 ) were 20-fold (p = 0.002) and 10-fold (0.001) lower than a cough (1260 (800-3242 [100-3682]) particles.l-1 ), respectively. This study demonstrates that facemask ventilation, even when performed with an intentional leak, does not generate high levels of bioaerosol. On the basis of this evidence, we argue facemask ventilation should not be considered an aerosol-generating procedure. [ABSTRACT FROM AUTHOR]

Introduction: Coronavirus disease 2019 (COVID-19) is a highly contagious disease transmitted by contact, droplets, and aerosols. Front line health-care workers (HCWs), particularly emergency physicians and acute care providers, are vulnerable to being exposed while treating their sick patients. Despite appropriate personal protective equipment use, HCW gets infected, suggesting the need for multiple layers of protection such as barrier devices. Methods: We aimed to determine the effectiveness of our novel "Resuscitation Cover All"(RCA) in reducing the exposure of HCW to simulated respiratory particles and its feasibility during cardio pulmonary resuscitation (CPR). This was a pilot simulation-based study. Five CPR simulation sessions were performed in Standard and RCA protocols, individually. Exposures through contact, droplets, and aerosols were simulated using a standardized volume of liquid detergent. Under Wood's lamp illumination, exposures of participants were compared between the protocols. Rate and depth of chest compressions, time taken to intubate, interruptions in CPR, and first-pass success were analyzed. Results: Overall mean exposure in standard protocol was 4950.4 ± 1461.6 (95%confidence interval [CI]:3135.7–6765.2) sq.pixels and RCA protocol was 2203.6 ± 1499.0 (95%CI: 342.4–4064.9) sq.pixels (P = 0.019). In standard, chest compressor had the highest exposure of 3066.6 ± 1419.2 (95%CI: 2051.3–4081.9) sq.pixels followed by defibrillator assistant 1166.4 ± 767.4 (95%CI: 617.4–1715.4) sq.pixels. Chest compressor of RCA had reduced exposure compared to that of standard (P < 0.001). Hands were the most frequently exposed body part. Airway manager of RCA had no exposure over head and neck in any session. No significant difference in CPR performance metrics was observed. Conclusion: This pilot simulation-based study shows that the novel RCA device could minimize the exposure of HCW to simulated respiratory particles during CPR. Also, it might not alter the high-quality CPR performance metrics. We need more real-life evidence. [ABSTRACT FROM AUTHOR]

Summary: Many guidelines consider supraglottic airway use to be an aerosol‐generating procedure. This status requires increased levels of personal protective equipment, fallow time between cases and results in reduced operating theatre efficiency. Aerosol generation has never been quantitated during supraglottic airway use. To address this evidence gap, we conducted real‐time aerosol monitoring (0.3–10‐µm diameter) in ultraclean operating theatres during supraglottic airway insertion and removal. This showed very low background particle concentrations (median (IQR [range]) 1.6 (0–3.1 [0–4.0]) particles.l−1) against which the patient's tidal breathing produced a higher concentration of aerosol (4.0 (1.3–11.0 [0–44]) particles.l−1, p = 0.048). The average aerosol concentration detected during supraglottic airway insertion (1.3 (1.0–4.2 [0–6.2]) particles.l−1, n = 11), and removal (2.1 (0–17.5 [0–26.2]) particles.l−1, n = 12) was no different to tidal breathing (p = 0.31 and p = 0.84, respectively). Comparison of supraglottic airway insertion and removal with a volitional cough (104 (66–169 [33–326]), n = 27), demonstrated that supraglottic airway insertion/removal sequences produced <4% of the aerosol compared with a single cough (p < 0.001). A transient aerosol increase was recorded during one complicated supraglottic airway insertion (which initially failed to provide a patent airway). Detailed analysis of this event showed an atypical particle size distribution and we subsequently identified multiple sources of non‐respiratory aerosols that may be produced during airway management and can be considered as artefacts. These findings demonstrate supraglottic airway insertion/removal generates no more bio‐aerosol than breathing and far less than a cough. This should inform the design of infection prevention strategies for anaesthetists and operating theatre staff caring for patients managed with supraglottic airways. [ABSTRACT FROM AUTHOR]

Limiting infection transmission is central to the safety of all in dentistry, particularly during the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Aerosol-generating procedures (AGPs) are crucial to the practice of dentistry; it is imperative to understand the inherent risks of viral dispersion associated with AGPs and the efficacy of available mitigation strategies. In a dental surgery setting, crown preparation and root canal access procedures were performed with an air turbine or high-speed contra-angle handpiece (HSCAH), with mitigation via rubber dam or high-volume aspiration and a no-mitigation control. A phantom head was used with a 1.5-mL min−1 flow of artificial saliva infected with Φ6-bacteriophage (a surrogate virus for SARS-CoV-2) at ~108 plaque-forming units mL−1, reflecting the upper limits of reported salivary SARS-CoV-2 levels. Bioaerosol dispersal was measured using agar settle plates lawned with the Φ6-bacteriophage host, Pseudomonas syringae. Viral air concentrations were assessed using MicroBio MB2 air sampling and particle quantities using Kanomax 3889 GEOα counters. Compared to an air turbine, the HSCAH reduced settled bioaerosols by 99.72%, 100.00%, and 100.00% for no mitigation, aspiration, and rubber dam, respectively. Bacteriophage concentrations in the air were reduced by 99.98%, 100.00%, and 100.00% with the same mitigations. Use of the HSCAH with high-volume aspiration resulted in no detectable bacteriophage, both on nonsplatter settle plates and in air samples taken 6 to 10 min postprocedure. To our knowledge, this study is the first to report the aerosolization in a dental clinic of active virus as a marker for risk determination. While this model represents a worst-case scenario for possible SARS-CoV-2 dispersal, these data showed that the use of HSCAHs can vastly reduce the risk of viral aerosolization and therefore remove the need for clinic fallow time. Furthermore, our findings indicate that the use of particle analysis alone cannot provide sufficient insight to understand bioaerosol infection risk. [ABSTRACT FROM AUTHOR]

Introduction: The COVID-19 pandemic has presented a significant challenge for infection prevention and control during airway management in anaesthesia and critical care. The protective barrier enclosure has been described and studied particularly for perioperative anaesthesia use. The potential use of the protective barrier enclosure during cardiopulmonary resuscitation has been poorly explored in the current literature. This work aims to demonstrate the potential of protective barrier enclosure in limiting aerosol dispersion during cardiopulmonary resuscitation delivery. Methods: A proof-of-concept simulation study was conducted to evaluate the protective properties of the protective barrier enclosure during cardiopulmonary resuscitation. Aerosol was simulated using a fluorescent dye trapped within the manikin. Three different methods of cardiopulmonary resuscitation delivery with a protective barrier enclosure applied over the manikin’s head were conducted. The first method simulated a chest compression only cardiopulmonary resuscitation, the second method also used chest compressions only, with a face mask fitted on the victim, while the third method, the victim was given chest compression and bag-valve-mask ventilation by two rescuers. Results: In the first method, release of aerosol from the manikin’s mouth was observed during chest compression, while in second method, most of the aerosol was trapped within the face mask, with only minor leaking. However, when bag-valve-mask ventilation was delivered, the aerosol leaked out at high speed around the bag-valve-mask seal. No aerosol condensation was found outside of the protective barrier enclosure in all scenes. Conclusion: Protective barrier enclosure may reduce aerosol exposure to the rescuers during out-of-hospital cardiac arrest.

Type 1 retinopathy of prematurity (ROP) requires emergency intervention and laser is an established modality of treatment. Laser treatment for ROP under topical anesthesia can be considered as an aerosol-generating procedure due to crying that puts health care workers at high risk of COVID-19 transmission. Aerosol containment box (ACB) is known to minimize aerosol transmission and there are reports of ROP laser done through incubator. Combining these two ideas, we describe a new application of ACB with suction for laser treatment of ROP thereby, reducing risk to health care team without compromising timely effective, and safe treatment for ROP.

Summary: Respirable aerosols (< 5 µm in diameter) present a high risk of SARS‐CoV‐2 transmission. Guidelines recommend using aerosol precautions during aerosol‐generating procedures, and droplet (> 5 µm) precautions at other times. However, emerging evidence indicates respiratory activities may be a more important source of aerosols than clinical procedures such as tracheal intubation. We aimed to measure the size, total number and volume of all human aerosols exhaled during respiratory activities and therapies. We used a novel chamber with an optical particle counter sampling at 100 l.min‐1 to count and size‐fractionate close to all exhaled particles (0.5–25 µm). We compared emissions from ten healthy subjects during six respiratory activities (quiet breathing; talking; shouting; forced expiratory manoeuvres; exercise; and coughing) with three respiratory therapies (high‐flow nasal oxygen and single or dual circuit non‐invasive positive pressure ventilation). Activities were repeated while wearing facemasks. When compared with quiet breathing, exertional respiratory activities increased particle counts 34.6‐fold during talking and 370.8‐fold during coughing (p < 0.001). High‐flow nasal oxygen 60 at l.min‐1 increased particle counts 2.3‐fold (p = 0.031) during quiet breathing. Single and dual circuit non‐invasive respiratory therapy at 25/10 cm.H2O with quiet breathing increased counts by 2.6‐fold and 7.8‐fold, respectively (both p < 0.001). During exertional activities, respiratory therapies and facemasks reduced emissions compared with activities alone. Respiratory activities (including exertional breathing and coughing) which mimic respiratory patterns during illness generate substantially more aerosols than non‐invasive respiratory therapies, which conversely can reduce total emissions. We argue the risk of aerosol exposure is underappreciated and warrants widespread, targeted interventions. [ABSTRACT FROM AUTHOR]

Background: The risk of transmission of SARS-CoV-2 from aerosols generated by medical procedures is a cause for concern.Aim: To evaluate the evidence for aerosol production and transmission of respiratory infection associated with procedures that involve airway suctioning or induce coughing/sneezing.Methods: The review was informed by PRISMA guidelines. Searches were conducted in PubMed for studies published between January 1st, 2003 and October 6th, 2020. Included studies examined whether nasogastric tube insertion, lung function tests, nasendoscopy, dysphagia assessment, or suctioning for airway clearance result in aerosol generation or transmission of SARS-CoV-2, SARS-CoV, MERS, or influenza. Risk of bias assessment focused on robustness of measurement, control for confounding, and applicability to clinical practice.Findings: Eighteen primary studies and two systematic reviews were included. Three epidemiological studies found no association between nasogastric tube insertion and acquisition of respiratory infections. One simulation study found low/very low production of aerosols associated with pulmonary lung function tests. Seven simulation studies of endoscopic sinus surgery suggested significant increases in aerosols but findings were inconsistent; two clinical studies found airborne particles associated with the use of microdebriders/drills. Some simulation studies did not use robust measures to detect particles and are difficult to equate to clinical conditions.Conclusion: There was an absence of evidence to suggest that the procedures included in the review were associated with an increased risk of transmission of respiratory infection. In order to better target precautions to mitigate risk, more research is required to determine the characteristics of medical procedures and patients that increase the risk of transmission of SARS-CoV-2. [ABSTRACT FROM AUTHOR]

The risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission to health care workers during myringotomy and tympanostomy tube (MT) insertion is unknown. To determine the need for enhanced precautions to prevent potential spread via aerosolized particles, we used an optical particle sizer to measure aerosol generation intraoperatively during a case series of MT insertion. We also discuss our institutional experience with safe pandemic-era perioperative practices. There was no measured increase in aerosol particle number during the procedure at a distance of 30 cm from the external auditory canal. These initial data are reassuring regarding the risk of SARS-CoV-2 transmission to the operating room team due to aerosol generation, but further study is necessary before making definitive recommendations. [ABSTRACT FROM AUTHOR]

From a local outbreak to a global pandemic, the severe acute respiratory syndrome-coronavirus-2 infection has spread across 210 borders to infect 2.5 million humans. There is an organized disruption in the routine hospital functioning to divert the available resources for effective crisis management; most of the departments have been split to carve out a “COVID task force.” The recommended indications for treatment of various medical conditions, medical procedures, and protocols have regressed on the evolutionary timeline. Newer recommendations are being released and updated regularly based on emerging evidence and experts' opinions. In view of exponential spread of the virus through routes already identified or those still elusive, the shedding of the virus during the incubation period, and lack of scientific evidence, the questions of “laparoscopy” or “no laparoscopy” assume importance. Herein, the evidence in literature pertaining to patient safety, efficient and effective utilization of hospital resources, and safety of health-care workers (HCWs) during the pandemic have been reviewed from the perspective of laparoscopy. The pathobiology of the virus including its survival properties and the different modes of transmission has been highlighted, and the relative risk to the HCWs between open and laparoscopic surgery dwelt upon. The recommendations from various international bodies have been discussed. Notwithstanding the absence of concrete evidence to exclude the possibility of bioaerosol-based transmission of the disease to the operating room staff, there is a multitude of other concerns which are addressed by avoiding the use of the laparoscope in the current scenario. Moreover, the absence of evidence is not evidence of absence; considering the high contagion and a long latent period associated with this virus, the onus is upon each individual surgeon to decide if one needs evidence of bioaerosol-based transmission or evidence in favor of safety before taking up 'laparoscopy' against 'open surgery'.

Purpose: To determine the particle size, concentration, airborne duration and spread during endoscopic endonasal pituitary surgery in actual patients in a theatre setting. Methods: This observational study recruited a convenience sample of three patients. Procedures were performed in a positive pressure operating room. Particle image velocimetry and spectrometry with air sampling were used for aerosol detection. Results: Intubation and extubation generated small particles (< 5 µm) in mean concentrations 12 times greater than background noise (p < 0.001). The mean particle concentrations during endonasal access were 4.5 times greater than background (p = 0.01). Particles were typically large (> 75 µm), remained airborne for up to 10 s and travelled up to 1.1 m. Use of a microdebrider generated mean aerosol concentrations 18 times above baseline (p = 0.005). High-speed drilling did not produce aerosols greater than baseline. Pituitary tumour resection generated mean aerosol concentrations less than background (p = 0.18). Surgical drape removal generated small and large particles in mean concentrations 6.4 times greater than background (p < 0.001). Conclusion: Intubation and extubation generate large amounts of small particles that remain suspended in air for long durations and disperse through theatre. Endonasal access and pituitary tumour resection generate smaller concentrations of larger particles which are airborne for shorter periods and travel shorter distances. [ABSTRACT FROM AUTHOR]

Background and Aim: During the Coronavirus Disease 2019 pandemic, esophagogastroduodenoscopy (EGD) has been recognized as an aerosol‐generating procedure. This study aimed to systematically compare the degree of face shield contamination between endoscopists who performed EGD on patients lying in the left lateral decubitus (LL) and prone positions. Methods: This is a randomized trial in patients scheduled for EGD between April and June 2020. Eligible 212 patients were randomized with 1:1 allocation. Rapid adenosine triphosphate test was used to determine contamination level using relative light units of greater than 200 as a cutoff value. All eligible patients were randomized to lie in either the LL or prone position during EGD. The primary outcome was the rate of contamination on the endoscopist's face shield. Results: The majority of patients were female (63%), with a mean age of 60 ± 13 years. Baseline characteristics were comparable between the two groups. There was no face shield contamination after EGD in either group. The number of coughs in the LL group was higher than the prone group (1.38 ± 1.8 vs 0.89 ± 1.4, P = 0.03). The mean differences in relative light units on the face shield before and after EGD in the LL and prone groups were 9.9 ± 20.9 and 4.1 ± 6 (P = 0.008), respectively. Conclusion: As measured by the adenosine triphosphate test, performing diagnostic EGD does not lead to contamination on the face shield of the endoscopist. However, placing patients in the prone position may further mitigate the risk. [ABSTRACT FROM AUTHOR]

Objectives: Many routine sinonasal procedures utilising powered instruments are regarded as aerosol‐generating. This study aimed to assess how different instrument settings affect detectable droplet spread and patterns of aerosolised droplet spread during simulated sinonasal surgery in order to identify mitigation strategies. Design: Simulation series using three‐dimensional (3‐D) printed sinonasal model. Fluorescein droplet spread was assessed following microdebriding and drilling of fluorescein‐soaked grapes and bones, respectively. Setting: University dry lab. Participants: 3‐D printed sinonasal model. Main outcome measures: Patterns of aerosolised droplet spread. Results and Conclusion: There were no observed fluorescein droplets or splatter in the measured surgical field after microdebridement of nasal polyps at aspecific irrigation rate and suction pressure. Activation of the microdebrider in the presence of excess fluid in the nasal cavity (reduced or blocked suction pressure, excessive irrigation fluid or bleeding) resulted in detectable droplet spread. Drilling with either coarse diamond or cutting burs resulted in detectable droplets and greater spread was observed when drilling within the anterior nasal cavity. High‐speed drilling is a high‐risk AGP but the addition of suction using a third hand technique reduces detectable droplet spread outside the nasal cavity. Using the instrument outside the nasal cavity inadvertently, or when unblocking, produces greater droplet spread and requires more caution. [ABSTRACT FROM AUTHOR]

Purpose: As surgical specialties now begin the graduated return to elective activity and face-to-face clinics, this paper investigates the current head and neck outpatient practices across the United Kingdom. Methods: A cross-sectional study comprised of an online 20-item survey was distributed to members of the British Association of Head & Neck Oncologists (BAHNO). The survey was open on a web-based platform and covered topics including safety measures for patients, protective equipment for healthcare staff and protocols for the use of flexible nasendoscopy in the clinic. Results: The survey was completed by 117 participants covering 66 NHS Trusts across the UK. There was a significant reduction in face-to-face Otolaryngology, Maxillofacial and Speech and Language clinic patients when compared to pre-pandemic numbers (p < 0.0001). Risk assessments for flexible nasendoscopy were done for 69% of clinics and 58% had an established protocol. Room downtime after flexible nasendoscopy ranged from 0 to 6 h and there was a significant increase in allocated downtime after a patient had coughed/sneezed (p < 0.001). Natural ventilation existed in 36% of clinics and the majority of responders didn't know the Air Change Per Hour (ACPH) of the clinic room (77%). Where ACPH was known, it often did not match the allocated room downtime. Conclusion: There is a wide variation in outpatient activity across the United Kingdom, but adaptations are being made to try and maintain staff and patient safety. However, more can still be done by liaising with allied teams to clarify outpatient protocols. [ABSTRACT FROM AUTHOR]

Rationale: There is an urgent need to understand the risk of viral transmission during nebulizer treatment of patients with coronavirus disease 2019 (COVID-19). Objectives: To assess the risk of transmitting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), SARS, Middle East respiratory syndrome (MERS), and influenza with administration of drugs via nebulizer. Methods: We searched multiple electronic databases, including PubMed®, China National Knowledge Infrastructure, Wanfang, preprint databases, and clinicaltrials.gov through December 1, 2020. Any study design in any language describing the risk of viral transmission with nebulizer treatment was eligible. Data were abstracted by one investigator and verified by a second. Results: We identified 22 articles: 1 systematic review, 7 cohort/case-control studies, 7 case series, and 7 simulation-based studies. Eight individual studies involved patients with SARS, five involved MERS, and one involved SARS-CoV-2. The seven cohort/case-control studies (four high risk of bias [ROB], three unclear ROB) found mixed results (median odds ratio 3.91, range 0.08–20.67) based on very weak data among a small number of health care workers (HCWs) with variable use of personal protective equipment (PPE). Case series had multiple potential contributors to transmission. Simulation studies found evidence for droplet dispersion after saline nebulization and measureable influenza viral particles up to 1.7 m from the source after 10 minutes of nebulization with a patient simulator. Study heterogeneity prevented meta-analysis. Conclusions: Case series raise concern of transmission risk, and simulation studies demonstrate droplet dispersion with virus recovery, but specific evidence that exposure to nebulizer treatment increases transmission of coronaviruses similar to COVID-19 is inconclusive. Tradeoffs balancing HCW safety and patient appropriateness can potentially minimize risk, including choice of delivery method for inhaled medications (e.g., nebulizer vs. metered dose inhaler) and PPE (e.g., N95 vs. surgical mask). [ABSTRACT FROM AUTHOR]

Apnoeic ventilation, COVID-19, nasal high-flow oxygen, aerosol-generating procedure, apnoeic oxygenation, THRIVE. [Extracted from the article]

Objectives: To determine whether common otolaryngology procedures generate viable aerosolized virus through a murine cytomegalovirus (mCMV) model for infection. Study Design: mCMV model of infection. Setting: University of Utah laboratory. Methods: Three-day-old BALB/c mice were inoculated with mCMV or saline. Five days later, each mouse underwent drilling, microdebrider, coblation, and electrocautery procedures. Particle size distribution and PM2.5 (particulate matter <2.5 µm) concentration were determined with a scanning mobility particle sizer and an aerosol particle sizer in the range of 15 nm to 32 µm. Aerosolized samples from these procedures were collected with an Aerosol Devices BioSpot sampler for viral titer based on polymerase chain reaction and for viable virus through viral culture. Results: As compared with the background aerosol concentrations, coblation and electrocautery showed statistically significant increases in airborne aerosols (Tukey-adjusted P value <.040), while microdebrider and drilling at 30,000 rpm did not (.870 < Tukey-adjusted P value <.930). We identified viral DNA in samples from coblation and drilling procedures, although we did not identify viable viruses in aerosol samples from any of the 4 procedures. Conclusion: Coblation and electrocautery procedures generate >100-fold increases in aerosol concentrations over background; only coblation and drilling produce aerosolized viral DNA. The high concentration of aerosols from coblation and electrocautery suggests the need for appropriate safeguards against particle exposure to health care workers. The presence of viral DNA from drilling and coblation procedures warrants the need for appropriate protection against droplet and aerosol exposure. [ABSTRACT FROM AUTHOR]

Since the onset of coronavirus disease 2019, the potential risk of dental procedural generated spray emissions (including aerosols and splatters), for severe acute respiratory syndrome coronavirus 2 transmission, has challenged care providers and policy makers alike. New studies have described the production and dissemination of sprays during simulated dental procedures, but findings lack generalizability beyond their measurements setting. This study aims to describe the fundamental mechanisms associated with spray production from rotary dental instrumentation with particular focus on what are currently considered high-risk components—namely, the production of small droplets that may remain suspended in the room environment for extended periods and the dispersal of high-velocity droplets resulting in formites at distant surfaces. Procedural sprays were parametrically studied with variables including rotation speed, burr-to-tooth contact, and coolant premisting modified and visualized using high-speed imaging and broadband or monochromatic laser light–sheet illumination. Droplet velocities were estimated and probability density maps for all laser illuminated sprays generated. The impact of varying the coolant parameters on heating during instrumentation was considered. Complex structured sprays were produced by water-cooled rotary instruments, which, in the worst case of an air turbine, included droplet projection speeds in excess of 12 m/s and the formation of millions of small droplets that may remain suspended. Elimination of premisting (mixing of coolant water and air prior to burr contact) resulted in a significant reduction in small droplets, but radial atomization may still occur and is modified by burr-to-tooth contact. Spatial probability distribution mapping identified a threshold for rotation speeds for radial atomization between 80,000 and 100,000 rpm. In this operatory mode, cutting efficiency is reduced but sufficient coolant effectiveness appears to be maintained. Multiple mechanisms for atomization of fluids from rotatory instrumentation exist, but parameters can be controlled to modify key spray characteristics during the current crisis. [ABSTRACT FROM AUTHOR]

Summary: The potential aerosolised transmission of severe acute respiratory syndrome coronavirus‐2 is of global concern. Airborne precaution personal protective equipment and preventative measures are universally mandated for medical procedures deemed to be aerosol generating. The implementation of these measures is having a huge impact on healthcare provision. There is currently a lack of quantitative evidence on the number and size of airborne particles produced during aerosol‐generating procedures to inform risk assessments. To address this evidence gap, we conducted real‐time, high‐resolution environmental monitoring in ultraclean ventilation operating theatres during tracheal intubation and extubation sequences. Continuous sampling with an optical particle sizer allowed characterisation of aerosol generation within the zone between the patient and anaesthetist. Aerosol monitoring showed a very low background particle count (0.4 particles.l−1) allowing resolution of transient increases in airborne particles associated with airway management. As a positive reference control, we quantitated the aerosol produced in the same setting by a volitional cough (average concentration, 732 (418) particles.l−1, n = 38). Tracheal intubation including facemask ventilation produced very low quantities of aerosolised particles (average concentration, 1.4 (1.4) particles.l−1, n = 14, p < 0.0001 vs. cough). Tracheal extubation, particularly when the patient coughed, produced a detectable aerosol (21 (18) l−1, n = 10) which was 15‐fold greater than intubation (p = 0.0004) but 35‐fold less than a volitional cough (p < 0.0001). The study does not support the designation of elective tracheal intubation as an aerosol‐generating procedure. Extubation generates more detectable aerosol than intubation but falls below the current criterion for designation as a high‐risk aerosol‐generating procedure. These novel findings from real‐time aerosol detection in a routine healthcare setting provide a quantitative methodology for risk assessment that can be extended to other airway management techniques and clinical settings. They also indicate the need for reappraisal of what constitutes an aerosol‐generating procedure and the associated precautions for routine anaesthetic airway management. [ABSTRACT FROM AUTHOR]

Background: Hazardous pathogens are spread in either droplets or aerosols produced during aerosol-generating procedures (AGP). Adjuncts minimising exposure of healthcare workers to hazardous pathogens released during AGP may be beneficial. We used state-of-the-art computational fluid dynamics (CFD) modelling to optimise the performance of a custom-designed shield.Methods: We modelled airflow patterns and trajectories of particles (size range 1-500 μm) emitted during a typical cough using CFD (ANSYS Fluent software, Canonsburg, PA, USA), in the presence and absence of a protective shield enclosing the head of a patient. We modelled the effect of different shield designs, suction tube position, and suction flow rate on particle escape from the shield.Results: Use of the shield prevented escape of 99.1-100% of particles, which were either trapped on the shield walls (16-21%) or extracted via suction (79-82%). At most, 0.9% particles remained floating inside the shield. Suction flow rates (40-160 L min-1) had no effect on the final location of particles in a closed system. Particle removal from within the shield was optimal when a suction catheter was placed vertically next to the head of the patient. Addition of multiple openings in the shield reduced the purging performance from 99% at 160 L min-1 to 67% at 40 L min-1.Conclusion: CFD modelling provides information to guide optimisation of the efficient removal of hazardous pathogens released during AGP from a custom-designed shield. These data are essential to establish before clinical use, pragmatic clinical trials, or both. [ABSTRACT FROM AUTHOR]

Objective: After significant restrictions initially due to the COVID-19 pandemic, otolaryngologists have begun resuming normal clinical practice. However, the risk of SARS-CoV-2 transmission to health care workers through aerosolization and airborne transmission during rhinologic surgery remains incompletely characterized. The objective of this study was to quantify the number concentrations of aerosols generated during rhinologic surgery with and without interventions involving 3 passive suction devices. Study Design: Cadaver simulation. Setting: Dedicated surgical laboratory. Subjects and Methods: In a simulation of rhinologic procedures with and without different passive suction interventions, the concentrations of generated aerosols in the particle size range of 0.30 to 10.0 µm were quantified with an optical particle sizer. Results: Functional endoscopic sinus surgery with and without microdebrider, high-speed powered drilling, use of an ultrasonic aspirator, and electrocautery all produced statistically significant increases in concentrations of aerosols of various sizes (P <.05). Powered drilling, ultrasonic aspirator, and electrocautery generated the highest concentration of aerosols, predominantly submicroparticles <1 µm. All interventions with a suction device were effective in reducing aerosols, though the surgical smoke evacuation system was the most effective passive suction method in 2 of the 5 surgical conditions with statistical significance (P <.05). Conclusion: Significant aerosol concentrations were produced in the range of 0.30 to 10.0 µm during all rhinologic procedures in this cadaver simulation. Rhinologic surgery with a passive suction device results in significant mitigation of generated aerosols. [ABSTRACT FROM AUTHOR]

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/cm3, 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. [ABSTRACT FROM AUTHOR]

Objective: The risk of SARS‐CoV‐2 transmission to healthcare workers through airborne aerosolization during otologic surgery has not been characterized. The objective of this study was to describe and quantify the aerosol generation during common otologic procedures in both cadaveric surgical simulation and live patient surgery. Methods: The number concentrations of generated aerosols in the particle size range of 0.30 to 10.0 μm were quantified using an optical particle sizer during both a cadaveric simulation of routine otologic procedures as well as cochlear implant surgery on live patients in the operating room. Results: In the cadaveric simulation, temporalis fascia graft harvest using cold techniques (without electrocautery) (n = 4) did not generate aerosols above baseline concentrations. Tympanoplasty (n = 3) and mastoidectomy (n = 3) both produced statistically significant increases in concentrations of aerosols (P < 0.05), predominantly submicron particles (< 1.0 μm). High‐speed, powered drilling of the temporal bone during mastoidectomy with a Multi Flute cutting burr resulted in higher peak concentrations and greater number of spikes in aerosols than with a diamond burr. In the operating room, spikes in aerosols occurred during both cochlear implant surgeries. Conclusion: In the cadaveric simulation, temporalis fascia graft harvest without electrocautery did not generate aerosol levels above baseline, while significant aerosol levels were generated during mastoidectomy and to a much less degree during tympanoplasty. Aerosol spikes were appreciated during cochlear implantation surgery in live patients. Level of Evidence: 2. [ABSTRACT FROM AUTHOR]

Importance Determine phacoemulsification cataract surgery risk in a Covid‐19 era. Background: SARS‐CoV‐2 (Covid‐19) transmission via microdroplet and aerosol‐generating procedures presents risk to medical professionals. As the most common elective surgical procedure performed globally; determining contamination risk from phacoemulsification cataract surgery may guide personal protection equipment use. Design Pilot study involving phacoemulsification cataract surgery on enucleated porcine eyes by experienced ophthalmologists in an ophthalmic operating theatre. Participants: Two ophthalmic surgical teams. Methods: Standardized phacoemulsification of porcine eyes by two ophthalmologists accompanied by an assistant. Fluorescein incorporated into phacoemulsification irrigation fluid identifying microdroplets and spatter. Contamination documented using a single‐lens reflex camera with a 532 nm narrow bandpass (fluorescein) filter, in‐conjunction with a wide‐field blue light and flat horizontal laser beam (wavelength 532 nm). Quantitative image analysis using Image‐J software. Main Outcome Measures: Microdroplet and spatter contamination from cataract phacoemulsification. Results: With phacoemulsification instruments fully within the eye, spatter contamination was limited to <10 cm. Insertion and removal of the phacoemulsification needle and bimanual irrigation/aspiration, with irrigation active generated spatter on the surgeons' gloves and gown extending to >16 cm below the neckline in surgeon 1 and > 5.5 cm below the neckline of surgeon 2. A small tear in the phacoemulsification irrigation sleeve, presented a worse‐case scenario the greatest spatter. No contamination above the surgeons' neckline nor contamination of assistant occurred. Conclusions and Relevance: Cataract phacoemulsification generates microdroplets and spatter. Until further studies on SARS‐CoV‐2 transmission via microdroplets or aerosolisation of ocular fluid are reported, this pilot study only supports standard personal protective equipment. [ABSTRACT FROM AUTHOR]

Objective: To review the literature on the definition of aerosol-generating procedures (AGPs), identify high-risk AGPs, guidelines to use personal protective equipment (PPE) and review evidence to see if electroconvulsive therapy (ECT) is a high-risk AGP requiring the use of PPE. Methods: Existing guidelines and research data were reviewed to answer the questions. Results: There is consensus about the type of anaesthesia used during ECT, what constitutes AGPs and what PPE should be used. It was not clear if ECT was an AGP, but we argue that it is one based on evidence. Conclusion: We conclude that ECT is an AGP and that it requires the appropriate use of PPE after taking in to account local supply and demand. [ABSTRACT FROM AUTHOR]

BACKGROUND: Exposure of respiratory therapists (RTs) during aerosol-generating procedures such as endotracheal intubation is an occupational hazard. Depending on the hospital, RTs may serve as laryngoscopist or in a role providing ventilation support and initiating mechanical ventilation. This study aimed to evaluate the potential exposure of RTs serving in either of these roles. METHODS: We set up a simulated patient with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in an ICU setting requiring endotracheal intubation involving a laryngoscopist, a nurse, and an RT supporting the laryngoscopist. All participants wore appropriate personal protective equipment (PPE). A fluorescent marker was sprayed by an atomizer during the procedure using 3 different methods for endotracheal intubation. The 3 techniques included PPE alone, a polycarbonate intubating box, or a coronavirus flexible enclosure, which consisted of a Mayo stand with plastic covering. The laryngoscopist and the supporting RT were assessed with a black light for contamination with the fluorescent marker. All simulations were recorded. RESULTS: When using only PPE, both the laryngoscopist and the RT were grossly contaminated. When using the intubating box, the laryngoscopist's contamination was detectable only on the gloves: the gown and face shield remained uncontaminated; the RT was still grossly contaminated on the gloves, gown, neck, and face shield. When using the coronavirus flexible enclosure system, both the laryngoscopist and the RT were better protected, with contamination detected only on the gloves of the laryngoscopist and the RT. CONCLUSIONS: Of the 3 techniques, the coronavirus flexible enclosure contained the fluorescent marker more effectively during endotracheal intubation than PPE alone or the intubating box based on exposure of the laryngoscopist and supporting RT. Optimizing containment during aerosol-generating procedures like endotracheal intubation is a critical component of minimizing occupational and nosocomial spread of SARS-CoV-2 to RTs who may serve as either the laryngoscopist or a support role. [ABSTRACT FROM AUTHOR]

Dental professionals are at high risk of contracting coronavirus disease 2019 (COVID-19) infection because of their scope of practice with aerosol-generating procedures. Recommendation by the Centers for Disease Control and Prevention to suspend elective dental procedures and avoid aerosol-generating procedures posed significant challenges in the management of patients presenting with endodontic emergencies and uncertainty of outcomes for endodontic procedures initiated, but not completed, before shutdown. The purpose of this study was to evaluate the success of palliative care on endodontic emergencies during the COVID-19 pandemic and to evaluate the stability of teeth with long-term Ca(OH) 2 placement because of delays in treatment completion. Patients presenting for endodontic emergencies during COVID-19 Shelter-in-Place orders received palliative care, including pharmacologic therapy and/or non–aerosol-generating procedural interventions. Part I of the study evaluated the effectiveness of palliative care, and need for aerosol-generating procedures or extractions was quantified. Part II of the study evaluated survivability and rate of adverse events for teeth that received partial or full root canal debridement and placement of calcium hydroxide before shutdown. Part I: Twenty-one patients presented with endodontic emergencies in 25 teeth during statewide shutdown. At a follow-up rate of 96%, 83% of endodontic emergencies required no further treatment or intervention after palliative care. Part II: Thirty-one teeth had received partial or full root canal debridement before statewide shutdown. Mean time to complete treatment was 13 weeks. At a recall rate of 100%, 77% of teeth did not experience any adverse events due to delays in treatment completion. The most common adverse event was a fractured provisional restoration (13%), followed by painful and/or infectious flare-up (6.4%), which were managed appropriately and therefore seemed successful. Only 1 tooth was fractured and nonrestorable (3%), leading to a failed outcome of tooth extraction. The remaining 4 outcome failures (13%) were due to patient unwillingness to undergo school-mandated COVID testing or patient unwillingness to continue treatment because of perceived risk of COVID infection. Palliative care for management of endodontic emergencies is a successful option when aerosol-generating procedures are restricted. This treatment approach may be considered in an effort to reduce risk of transmission of COVID-19 infection during subsequent shutdowns. Prolonged Ca(OH) 2 medicament because of COVID-19 related delays in treatment completion appeared to have minimal effect on survival of teeth. [ABSTRACT FROM AUTHOR]