Clinical characterization of respiratory large droplet production during common airway procedures using high-speed imaging

Abstract

During the COVID-19 pandemic, a significant number of healthcare workers have been infected with SARS-CoV-2. However, there remains little knowledge regarding large droplet dissemination during airway management procedures in real life settings. 12 different airway management procedures were investigated during routine clinical care. A high-speed video camera (1000 frames/second) was for imaging. Quantitative droplet characteristics as size, distance traveled, and velocity were computed. Droplets were detected in 8/12 procedures. The droplet trajectories could be divided into two distinctive patterns (type 1/2). Type 1 represented a ballistic trajectory with higher speed large droplets whereas type 2 represented a random trajectory of slower particles that persisted longer in air. The use of tracheal cannula filters reduced the amount of droplets. Respiratory droplet patterns generated during airway management procedures follow two distinctive trajectories based on the influence of aerodynamic forces. Speaking and coughing produce more droplets than non-invasive ventilation therapy confirming these behaviors as exposure risks. Even large droplets may exhibit patterns resembling the fluid dynamics smaller airborne aerosols that follow the airflow convectively and may place the healthcare provider at risk.

Evaluation of Respiratory Particle Emission during Otorhinolaryngological Procedures in the Context of the SARS-CoV-2 Pandemic

“…Since it is common for patients to speak or cough during otoscopy and sonography, subjects were saying aloud the phrase “Stay healthy” and afterwards coughed once within a measuring cycle to simulate the worst-case scenario. The phrase was chosen for its benchmark status [ 14 , 29 ]. For the whole tasks, two cycles of “Stay healthy” and coughing were executed by each subject.…”

“…The measuring principle for the droplet experiments was analogue to Mueller et al (2021) [ 29 ] with an optimized stationary setup shown in Figure 1 . Subjects were recorded in front of a professional black photography background.…”

“…Otoscopy was only performed with masks since there is no clinical indication or limitation regarding the procedure for the patient to wear none. The measuring principle for the droplet experiments was analogue to Mueller et al (2021) [29] with an optimized stationary setup shown in Figure 1. Subjects were recorded in front of a professional black photography background.…”

Inhaled hydrogel-based microspheres for management of COVID-19: A new sweeper biological platform

“…Therefore, inspired by the habit of sweeper fishes in the aquarium to attach to rocks and glass to stabilize the body, the authors attached these cell membranes on inhaled microfluidic hydrogel microspheres to improve their accumulation in the respiratory system. Since the deposition site of microspheres is determined by their aerodynamic diameter (Dare) in the respiratory system, 8 for the “sweeper” system to work, the authors must precisely control the Dare of microspheres at 7.89, 6.63, and 4.21 μm. In this way, these microspheres accumulated in the oropharynx, upper airway, and lower airway of the lung lobes, leading to the protection of the whole respiratory tract against the virus and potentially reducing the viral transmission in humans.…”

Peak risk of SARS-CoV-2 infection within 5 s of face-to-face encounters: an observational/retrospective study

“…From the early days of the coronavirus disease 2019 (COVID-19) pandemic to much of 2020, the World Health Organization (WHO) strongly believed that severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus responsible for COVID-19, primarily spreads through larger respiratory droplets expelled by infected individuals while coughing, sneezing, or speaking 1 – 4 . However, reports of numerous airborne transmission possibilities have emerged, including outbreaks at the Wuhan hospital 5 and a restaurant in Guangzhou 6 – 9 .…”