Aerosol Generation During Laryngology Procedures in the Operating Room.

OBJECTIVE: Severe acute respiratory syndrome coronavirus-2 spreads through respiratory fluids. We aim to quantify aerosolized particles during laryngology procedures to understand their potential for transmission of infectious aerosol-based diseases. STUDY DESIGN: Prospective quantification of aerosol generation. METHODS: Airborne particles (0.3-25 µm in diameter) were measured during live-patient laryngology surgeries using an optical particle counter positioned 60 cm from the oral cavity to the surgeon's left. Measurements taken during the procedures were compared to baseline concentrations recorded immediately before each procedure. Procedures included direct laryngoscopy with general endotracheal anesthesia (GETA), direct laryngoscopy with jet ventilation, and carbon dioxide (CO2 ) laser use with or without jet ventilation, all utilizing intermittent suction. RESULTS: Greater than 99% of measured particles were 0.3 to 1.0 µm in diameter. Compared to baseline, direct laryngoscopy was associated with a significant 6.71% increase in cumulative particles, primarily 0.3 to 1.0 µm particles (P < .0001). 1.0 to 25 µm particles significantly decreased (P < .001). Jet ventilation was not associated with a significant change in cumulative particles; when analyzing differential particle sizes, only 10 to 25 µm particles exhibited a significant increase compared to baseline (+42.40%, P = .002). Significant increases in cumulative particles were recorded during CO2 laser use (+14.70%, P < .0001), specifically in 0.3 to 2.5 µm particles. Overall, there was no difference when comparing CO2 laser use during jet ventilation versus GETA. CONCLUSIONS: CO2 laser use during laryngology surgery is associated with significant increases in airborne particles. Although direct laryngoscopy with GETA is associated with slight increases in particles, jet ventilation overall does not increase particle aerosolization. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2759-2765, 2021.

Emergency Tracheal Intubation in Patients with COVID-19: A Single-center, Retrospective Cohort Study.

INTRODUCTION: The objective of this study was to compare airway management technique, performance, and peri-intubation complications during the novel coronavirus pandemic (COVID-19) using a single-center cohort of patients requiring emergent intubation. METHODS: We retrospectively collected data on non-operating room (OR) intubations from February 1-April 23, 2020. All patients undergoing emergency intubation outside the OR were eligible for inclusion. Data were entered using an airway procedure note integrated within the electronic health record. Variables included level of training and specialty of the laryngoscopist, the patient's indication for intubation, methods of intubation, induction and paralytic agents, grade of view, use of video laryngoscopy, number of attempts, and adverse events. We performed a descriptive analysis comparing intubations with an available positive COVID-19 test result with cases that had either a negative or unavailable test result. RESULTS: We obtained 406 independent procedure notes filed between February 1-April 23, 2020, and of these, 123 cases had a positive COVID-19 test result. Residents performed fewer tracheal intubations in COVID-19 cases when compared to nurse anesthetists (26.0% vs 37.4%). Video laryngoscopy was used significantly more in COVID-19 cases (91.1% vs 56.8%). No difference in first-pass success was observed between COVID-19 positive cases and controls (89.4% vs. 89.0%, p = 1.0). An increased rate of oxygen desaturation was observed in COVID-19 cases (20.3% vs. 9.9%) while there was no difference in the rate of other recorded complications and first-pass success. DISCUSSION: An average twofold increase in the rate of tracheal intubation was observed after March 24, 2020, corresponding with an influx of COVID-19 positive cases. We observed adherence to society guidelines regarding performance of tracheal intubation by an expert laryngoscopist and the use of video laryngoscopy.

Unintended consequences: The impact of airway management modifications introduced in response to COVID-19 on intubations in a tertiary centre emergency department.

OBJECTIVE: In response to COVID-19, we introduced and examined the effect of a raft of modifications to standard practice on adverse events and first-attempt success (FAS) associated with ED intubation. METHODS: An analysis of prospectively collected registry data of all ED intubations over a 3-year period at an Australian Major Trauma Centre. During the first 6 months of the COVID-19 pandemic in Australia, we introduced modifications to standard practice to reduce the risk to staff including: aerosolisation reduction, comprehensive personal protective equipment for all intubations, regular low fidelity simulation with 'sign-off' for all medical and nursing staff, senior clinician laryngoscopist and the introduction of pre-drawn medications. RESULTS: There were 783 patients, 136 in the COVID-19 era and 647 in the pre-COVID-19 comparator group. The rate of hypoxia was higher during the COVID-19 era compared to pre-COVID-19 (18.4% vs 9.6%, P < 0.005). This occurred despite the FAS rate remaining very high (95.6% vs 93.8%, P = 0.42) and intubation being undertaken by more senior laryngoscopists (consultant 55.9% during COVID-19 vs 22.6% pre-COVID-19, P < 0.001). Other adverse events were similar before and during COVID-19 (hypotension 12.5% vs 7.9%, P = 0.082; bradycardia 1.5% vs 0.5%, P = 0.21). Video laryngoscopy was more likely to be used during COVID-19 (95.6% vs 82.5%, P < 0.001) and induction of anaesthesia more often used ketamine (66.9% vs 42.3%, P < 0.001) and rocuronium (86.8% vs 52.1%, P < 0.001). CONCLUSIONS: This raft of modifications to ED intubation was associated with significant increase in hypoxia despite a very high FAS rate and more senior first laryngoscopist.

The FEES box: A novel barrier to contain particles during aerosol-generating procedures.

PURPOSE: Due to the COVID-19 pandemic, aerosol-generating procedures (AGPs) such as flexible endoscopic evaluation of swallowing (FEES) have been deemed high-risk and in some cases restricted, indicating the need for additional personal protective equipment. The aim of this study was to erect and study a protective barrier for FEES. MATERIALS AND METHODS: A PVC cube was constructed to fit over a patient while allowing for upright endoscopy. A plastic drape was fitted over the cube, and the protective barrier was subsequently named the "FEES Box." Three different particulate-generating tasks were carried out: sneezing, coughing, and spraying water from an atomizer bottle. Each task was completed within and without the FEES Box, and particulate was measured with a particle counter. The average particles/L detected during the three tasks, and baseline measurements, were statistically compared. RESULTS: Without the FEES Box in place, the sneezing and spraying tasks resulted in a statistically significant increase in particles above baseline (p < 0.001 and p = 0.004, respectively); coughing particulate never reached levels significantly higher than baseline (p = 0.230). With use of the FEES Box, there was no statistically significant increase in particles above baseline in any of the three tasks. CONCLUSION: The FEES Box effectively contained particles generated during sneezes and an atomizer spray. It would also likely mitigate coughing particulate, but coughing did not generate a significant increase in particles above baseline. Further research is warranted to test the efficacy of the FEES Box in containing particulate matter during a complete FEES procedure.

Is Office Laryngoscopy an Aerosol-Generating Procedure?

OBJECTIVES/HYPOTHESIS: The aims of this work were 1) to investigate whether office laryngoscopy is an aerosol-generating procedure with an optical particle sizer (OPS) during clinical simulation on healthy volunteers, and 2) to critically discuss methods for assessment of aerosolizing potentials in invasive interventions. STUDY DESIGN: Prospective quantification of aerosol and droplet generation during clinical simulation of rigid and flexible laryngoscopy. METHODS: Two healthy volunteers were recruited to undergo both flexible and rigid laryngoscopy. An OPS was used to quantify aerosols and droplets generated for four positive controls relative to ambient particles (speech, breathing, /e/ phonation, and /ae/ phonation) and for five test interventions relative to breathing and phonation (flexible laryngoscopy, flexible laryngoscopy with humming, flexible laryngoscopy with /e/ phonation, rigid laryngoscopy, and rigid laryngoscopy with /ae/ phonation). Particle counts in mean diameter size range from 0.3 to >10 µm were measured with OPS placed at 12 cm from the subject's nose/mouth. RESULTS: None of the laryngoscopy interventions (n = 10 each) generated aerosols above that produced by breathing or phonation. Breathing (n = 40, 1-3 µm, P = .016) and /ae/ phonation (n = 10, 1-3 µm, P = .022; 3-5 µm. P = .083; >5 µm, P = .012) were statistically significant producers of aerosols and droplets. Neither speech nor /e/ phonation (n = 10 each) were associated with statistically significant aerosols and droplet generation. CONCLUSIONS: Using OPS to detect droplets and aerosols, we found that office laryngoscopy is likely not an aerosol-generating procedure. Despite its prior use in otolaryngological literature, an OPS has intrinsic limitations. Our study should be complemented with more sophisticated methods of droplet distribution measurement. LEVEL OF EVIDENCE: 3 Laryngoscope, 130:2637-2642, 2020.

A Flexible Enclosure to Protect Respiratory Therapists During Aerosol-Generating Procedures.

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.

Droplet Exposure Risk to Providers From In-Office Flexible Laryngoscopy: A COVID-19 Simulation.

To provide data on risk of respiratory droplets from common otolaryngologic procedures during the COVID-19 pandemic, a novel simulation of droplet exposure from flexible laryngoscopy was performed. After completion of a nasal symptom questionnaire, topical fluorescein spray was administered into the nasal and oropharynx of 10 healthy volunteers, who then underwent flexible laryngoscopy under 2 conditions: routine without provoked response and with prompted sneeze/cough. After each, droplets on the proceduralist and participant were counted under ultraviolet A light. Droplets were observed on 1 of 10 volunteers after routine laryngoscopy and 4 of 10 during laryngoscopy with sneeze/cough. A nasal symptom score based on congestion and rhinorrhea was significantly elevated among droplet producers after sneeze/cough (P = .0164). No droplets were observed on the provider. Overall, with adequate personal protective equipment, flexible laryngoscopy poses minimal droplet risk to providers. Nasal symptoms can identify patients more likely to produce droplets after sneeze/cough.

Risk of SARS-CoV-2 Transmission During Flexible Laryngoscopy: A Systematic Review.

IMPORTANCE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reportedly infected otolaryngologists disproportionately in the early parts of the coronavirus disease 2019 pandemic. Recommendations from national and international health organizations suggest minimizing the use of flexible laryngoscopy as a result. OBJECTIVE: To review evidence on the risks of aerosolization and transmission of SARS-CoV-2 from patients to health care personnel during endoscopy of the upper aerodigestive tract. EVIDENCE REVIEW: A comprehensive review of literature was performed on April 19, 2020, using the PubMed/MEDLINE (1966-April 2020), Embase (1975-April 2020), and Web of Science (1900-April 2020) databases. All English-language primary research studies were included if they assessed the transmission of SARS-CoV-2 or SARS-CoV-1 during procedures in the upper aerodigestive tract. The primary outcome measure was disease transmission among health care workers. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for accuracy of reporting. FINDINGS: The queries for SARS-CoV-2 and SARS-CoV-1 identified 6 articles for systematic review. No studies included in this review provided data for SARS-CoV-2 transmission during flexible laryngoscopy. A total of 204 of 1264 health care workers (16.1%) had procedure-specific infections of SARS-CoV-1 or SARS-CoV-2. Among those, 53 of 221 (24.0%) were exposed during intubation, 1 of 15 (6.7%) during bronchoscopy, and 1 of 1 (100%) during endoscopy-assisted intubation. CONCLUSIONS AND RELEVANCE: A substantial lack of research precludes formal conclusions about the safety of flexible laryngoscopy and transmission of SARS-CoV-2 from patients to health care workers. The use of appropriate precautionary measures and personal protective equipment appears to reduce the risk of transmission. Given the uncertainty in transmission and the known benefits of safety precautions, upper airway endoscopy may be reasonable to perform if precautionary steps are taken.

Respiratory viral panels and pediatric airway evaluation: The role of testing for upper respiratory infections to stratify perioperative risk.

OBJECTIVES: Children admitted with stridor and respiratory distress comprise a complex patient group that requires the otolaryngologist to decide when to assess and intervene with direct laryngoscopy and bronchoscopy (DLB). Historically, the diagnosis of viral upper respiratory tract infection (URTI) can lead to postponement of surgery due to concerns of perioperative complications related to acute illness. Respiratory viral panels (RVP) are often used to confirm the presence of recent or active viral infection and can affect the differential diagnosis of upper airway obstruction. This study examined whether positive RVP testing is associated with perioperative complications and operative findings in pediatric patients undergoing inpatient DLB. METHODS: A retrospective chart review of 132 pediatric patient encounters was performed. Viral testing results, DLB indication, DLB findings, and perioperative complications were compared. RESULTS: Sixty encounters (45.5%) involved a positive RVP, and 72 (54.5%) involved a negative RVP. Those with positive RVP were less likely to have a preoperative structural airway diagnosis (P =.0250) and more likely to have a history of recurrent upper respiratory infections (P =.0464). The most common reason for DLB was the need to assess the airway due to concern for structural pathology. Anatomic abnormalities were seen in a majority of encounters (77.3%) Laryngospasm occurred in 1 (1.7%) RVP positive and 1 (1.4%) RVP negative encounter, and 2 (2.8%) RVP negative encounters required reintubation. No other major complications were observed. No association was noted between RVP results and incidence of major or minor complication. CONCLUSIONS: Major perioperative complications after surgical intervention with DLB for the management of complex, inpatient children with stridor and respiratory distress are rare. RVP positivity, specific pathogens identified on RVP, and presence of URI symptoms were not associated with perioperative complications.