Letter to the Editor New Design for Aerosol Protection During Endotracheal Intubation in the Coronavirus Disease 2019 (COVID-19) Pandemic Era: The “Anti-Aerosol Igloo” (AAI)

As a result of the coronavirus disease 2019 (COVID-19) pandemic and its transmission through coughing and breathing in aerosols, the need to seek more and better protection methods for health personnel (i.e., personal protective equipment) has snowballed. Particles that are expelled when speaking or while coughing can travel up to 2 meters, of which those greater than 5 microns fall on different surfaces and those that are smaller can remain suspended in the air for several hours.

On March 3, 2020, the World Health Organization called on the industry and governments to increase personal protective equipment production by 40% to meet growing global demand. New ideas to reduce the risks of contagion caused by the expulsion of contaminated particles during the endotracheal intubation process began to appear On March 23, 2020, a Taiwanese newspaper (Taiwan News) reported Dr. Lai Hsien-Yung's idea to create an acrylic box that is placed over a patient's head and neck, allowing adequate protection for physicians and auxiliary staff during the intubation maneuver. He called this box the “aerosol box.” This box enables easy intubation because it is performed under direct visualization and allows the physician to introduce his or her arms inside this box. Because of its utility, its use goes beyond surgery, including the emergency department or the intensive care unit setting.¹

The critical protection provided by this box has been demonstrated by Canelli et al.² in a simulation test with a dummy that generates coughs and expels drops and aerosols of a fluorescent dye previously placed in the hypopharynx. During the last few weeks, the aerosol box has begun to be used in multiple countries around the world, with various types of modifications. We observed versions in different materials, all of them assembled through the combination of separate pieces, and all of them in orthogonal shapes with corners and vertices that easily house polluting substances, making their cleansing particularly tricky. In addition, the materials used are heavy acrylics and thus susceptible to damage and decay. Boxes of various dimensions and arrangements have been built: partially closing the front of the face, opening additional side hole(s), placing a virus filter on one of its side faces, etc.³

Inspired by these first attempts, but well aware of their shortcomings, we designed a seamless, single-piece element shaped like an igloo. We have successfully tested our design, the Anti-Aerosol Igloo (AAI), in surgery rooms and the intensive care unit of Los Cobos Medical Center in Bogotá, Colombia.

New Model: AAI, IsolMed

Properties

• 1)Its rounded shape allows for its anterior face to be almost completely closed, significantly reducing the exit or expulsion of microdroplets and aerosols through this route (Figure 1 ).
• 2)The AAI is built with a single piece of polyethylene terephthalate, which has the following advantages:
• a.Easy to sterilize and disinfect: 100% sterilization and disinfection of the AAI is possible using conventional disinfectants as well as gamma rays and ethylene oxide. Box models made of 5–8 interlocking parts are much harder to clean and have corners, vertices, or seams in which contaminates can hide and accumulate.
• b.Lightweight (1 kg/2.2 lbs.) and durable. The AAI's polyethylene terephthalate material has excellent flexibility and is resistant to bumps and dings. Box models made of interconnected parts composed of heavier, inflexible materials are much more susceptible to disjointing and damage.
• c.Intubation made easier and safer. The curved profile and elasticity of the AAI material (3 mm thick) facilitates the process of intubation while minimizing the risks of coming into contact with contaminates trapped in the seams of the box model (Figure 2 ).
• d.Ergonomic design. The dome shape of the AAI allows for the medical specialist to conduct intubation more ergonomically.
• e.Cost-effective. The AAI is cheaper to produce than other models.

Figure 1.

Anti-Aerosol Igloo design. Single-piece chamber for medical crew protection during endotracheal intubation and extubation.

Figure 2.

Operating room pictures depicting the feasibility of the endotracheal intubation process using the Anti-Aerosol Igloo (AAI). (A) Dummy's head and neck after endotracheal intubation inside the AAI box. Please note that the AAI transparent box has 2 windows for the physician's arms to be introduced during endotracheal intubation. (B) Easy preoxygenation before the intubation. (C) Easy endotracheal intubation using a GlideScope. (D) Connection of the endotracheal tube to the breathing machine. (E) Easy endotracheal tube securing with tape. (F) Removal of the AAI to proceed with the surgical intervention.