Emergency cricothyrotomy during the COVID-19 pandemic: how to suppress aerosolization

Background

Emergency surgical airway, cricothyrotomy, is an aerosol-producing procedure that increases the risk of infection for healthcare providers particularly during epidemics or pandemics.1 2 National and international healthcare organizations have provided safety guidelines for airway management and for non-emergent tracheostomy procedures, but there is little information on how to suppress aerosolization when performing emergent surgical airways, that is, cricothyrotomy. There are no known practical recommendations on how to suppress aerosolization and splatter apart from those published in May 2020 by the American Association for the Surgery of Trauma, which recommends that ventilation should be stopped as a measure to decrease the generation of aerosolized matter but did not address suppression of active aerosolization.3 During early March 2020, we were faced with escalating numbers of emergency intubations for patients with COVID-19 or suspected cases that had the potential to require cricothyrotomy at Northwestern Memorial Hospital in Chicago, Illinois, USA. To address concerns about aerosolization during this emergency (often bedside) procedure, a taskforce of ear, nose and throat surgeons and trauma/critical surgeon developed and evaluated three methods to suppress aerosolization during cricothyrotomy. The following study describes the approach this group of surgeons undertook to reach institutional practice recommendations for performing cricothyrotomy on suspected or proven cases of COVID-19.

Methods

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.

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.

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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.

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Results

The five surgeons agreed that all three drapes offered aerosol suppression. They also agreed that using the sterile see-through X-ray cassette drape to cover the neck while performing cricothyrotomy allowed for the best visualization and that it was easy to manipulate. However, this drape did not allow a firm seal around the surgeon’s hands, which allowed aerosolized materials to escape and cause contamination of the surgeon and the healthcare team. The dry OR towels were easy to manipulate but hindered visualization and easily slipped off the surgeon’s hands, again exposing the surgeon to the aerosolization of materials from the airway. When using the wet OR towels to cover the operative site, all five surgeons agreed that the wet towels remained over the hands of the surgeon during the procedure. When discussing their observations from the black light test, they all agreed that all three drapes provided suppression of the aerosolization but that was dependent of how well the drape stayed covering the procedure field (see online supplementary video 1). Moreover, the surgeon-investigators reached a consensus advocating the use of wet towels during cricothyrotomy but acknowledged that while the reduction of the aerosolization using the wet towels came at the expense of some of the visibility, it did not hinder the ability to perform the procedure safely because cricothyrotomy is dependent on the tactile identification of the anatomical landmarks more than depending on visual cues. Table 1 summarizes the conclusion reached by the group of investigators.

Discussion

We illustrate the effectiveness of using wet towels to suppress aerosolization during the performance of a cricothyrotomy procedure on a locally developed hybrid simulator. This technique, using wet towels, takes advantage of the cheap and readily available cloth towels that do not require extra investment in time, money or efforts and is suitable to all healthcare settings, poor and wealthy. Additionally, experienced surgeons can easily rely on their tactile senses to perform cricothyrotomy using anatomic landmarks. The surgeons acknowledged that the increased safety that wet towels provide comes at the expense of compromising the visual cues, but they all agreed that this did not compromise the efficiency and accuracy of performing the procedure given that cricothyrotomy is dependent on tactile identification of the anatomical landmarks and not on visual cues. We recommend the deployment of wet towels as a safety measure when performing cricothyrotomy regardless of the instrument used (eg, tracheostomy tube or cricothyrotomy tube) or whether the surgeons choose a different procedural technique not employing a bougie.

Other innovative techniques for airway surgery have been developed during the COVID-19 pandemic to enhance the safety of healthcare providers by suppressing aerosolization. These innovations include the use of see-through C-arm covers with suction to create a negative pressure space when performing tracheostomy,7 the use of a metal frame set and a see-through C-arm cover to perform tracheostomy8 and using double drapes when performing mastoidectomy.9 All these innovative techniques are well suited for the OR where resources are readily available. We believe our technique is well suited for performing emergent cricothyrotomy either inside or outside of the OR (eg, in the ED or at the patient’s bedside). Additionally, using wet towels is inexpensive and can be easily used in healthcare systems where personal protective equipment (PPE) or ORs may not be readily available. However, we do stress the importance of using full PPE including face shields and N95 masks or a Powered Air-Purifying Respirators (PARP) whenever available. It is also important to emphasize that airway management of patients with suspected or proven COVID-19 should comply with national and international guidelines including cessation of ventilations and using negative pressure rooms for all airway procedures.10

Conclusions

Wet OR towels suppress aerosolization during cricothyrotomy on a locally developed hybrid simulator. Based on our findings, we recommended its use as a barrier against aerosolization in all cricothyrotomy procedures at our institution. We share our investigative methodology and experimental findings with the larger community of healthcare providers for the greater benefit during the COVID-19 pandemic or other potentially infective disease processes. At the conclusion of our work, we decided to create a simulation-based educational program to train all those involved in performing cricothyrotomy at our institution (residents, fellows and attendings).