Five board-certified surgeons (4 ear, throat and nose surgeons and one trauma/critical care surgeon) used a locally developed hybrid simulator with a porcine trachea to test three methods to suppress aerosolization during cricothyrotomy at the Northwestern Simulation Laboratory, Northwestern University Feinberg School of Medicine. The surgeons agreed on standard procedural steps for cricothyrotomy. The group adopted a previously described technique ‘Scalpel–Bougie–Tube’ approach, which is based on Seldinger technique using a bougie as a guide.4–6 Box 1 lists the cricothyrotomy procedural steps that were implemented by the surgeons.
Box 1Procedural steps for cricothyrotomy using the Scalpel–Bougie–Tube technique
Cricothyrotomy procedure steps
Palpate the thyroid notch and cricoid cartilage. Use the thumb and middle finger of your non-dominant hand to fix the tracheo-laryngeal complex in position.
Use size 10 scalpel to create a 3–5 cm vertical skin incision starting inferior to the thyroid notch.
Use a hemostat to reach the cricothyroid membrane.
Use the scalpel to incise the membrane horizontally.
Remove scalpel and insert your non-dominant index finger until you reach the posterior wall of the airway.
Deliver the bougie with the ETT mounted on it into the trachea along your index finger directing it inferiorly toward the carina.
Slide the size 6 ETT over the bougie into the airway. Do not advance the tube beyond 5 cm into the trachea.
Inflate the ETT balloon and withdraw the bougie.
Then in a two-step process, the group of surgeons evaluated the effectiveness of using a see-through X-ray cassette drape, dry operating room (OR) towels and wet OR towels as neck coverings to suppress aerosolization during cricothyrotomy. figure 1 shows the three types of drapes that were used in the experiments. These particular materials were chosen because they are readily available in the emergency department (ED) where most potential cases take place. We did not include the larger C-arm fluoroscopy drape because it is not readily available in the ED.
In the first step of the experiment, the five surgeons performed the surgical cricothyrotomy procedure independently. Each surgeon was provided with a cricothyrotomy simulator containing a swine trachea and the three types of drapes; trachea replacements were provided if needed. The criteria used to evaluate each of the three coverings were the following: is it easy to use; does it cover the hands of the surgeon through the whole procedure; and does it hinder the procedural steps. The surgeons were also instructed to identify the best orientation of the drape that allows the maximum versatility and least hindrance to performing the procedure.
In the second step, the surgeons injected fluorescein dye through an atomizer, representing aerosolized material, placed into the lower end of the porcine trachea when the surgeon was cutting into the cricothyroid membrane to evaluate the effectiveness of each of the three drapes (figure 2). We then shined a black light on the surgical field to assess the contamination of aerosolized fluorescein on the surgeon and healthcare providers’ gowns and face shields (see online supplementary video 1). The testing of each drape with atomized fluorescein dye and the black light was repeated twice with two different surgeons while witnessed by the rest of the team. The surgeons then met as a group to discuss their individual experience with each type of drape and their assessment of the fluorescein dye test to reach consensus on which drape to recommend for use during emergent cricothyrotomy on known or suspected patients with COVID-19.