Introduction
Open tracheostomy poses a high-risk for healthcare workers given that it is an aerosol-generating procedure. The aerosol produced during such procedures may suspend infectious agents in the surrounding environment for up to a few hours.Reference van Doremalen, Bushmaker, Morris, Holbrook, Gamble and Williamson1
Many guidelines have been proposed during the pandemic to reduce the risk of infection, to healthcare workers especially. Adequate personal protective equipment (PPE) measures should be adopted.Reference Mick and Murphy2 An aerosol box is a recently recommended barrier protection device for use during endotracheal intubation, which provides added protection and contains the potentially infectious agents.Reference Canelli, Connor, Gonzalez, Nozari and Ortega3 The use of such barrier protection will benefit regions where there is a shortage of PPE and will give protection against asymptomatic false-negative cases.
Filho et al. proposed a protective box (a Covid box) for open tracheostomy.Reference Filho, Teles, da Fonseca, Filho, Pereira and Pontes4 This box comprised a metallic frame covered with a transparent sheet. Ports were made on the side according to the comfort of the surgeon, with cross-shaped incisions in the sheet. However, the authors concluded there is a chance of air leak through the base of the box and hand ports. Moreover, the risk of plastic sheets getting torn during the procedure may lead to aerosol leakage.
Bertroche et al. attempted tracheostomy in a negative-pressure environment created with the help of plastic sheets.Reference Bertroche, Pipkorn, Zolkind, Buchman and Zevallos5 The sheets were readily available, and the surgeon again could make ports according to comfort. However, the risk of leakage through these ports remained a concern. Further, the transparent plastic sheets have an inherent disadvantage of suboptimal vision, associated with the distortion created by the uneven surface due to the material's flexibility, which is undesirable in any surgical procedure. Acrylic boxes used in intubation, however, have not been used for any surgery to date.
Materials and methods
Protective box description
We present a prototype of a barrier enclosure made of transparent acrylic material for tracheostomy. Institute ethical clearance (approval code: AIIMS/IEC/2020/3192) was obtained prior to using the box.
The box was designed to provide a seal all around, including at the base and front of the box, with the help of detachable sheets fixed by an adhesive margin on the box. The patient lies on the base sheet. The box is affixed onto the table, to prevent it from falling off. The base and front sheets can be removed quickly and the box can be taken away, if any need arises.
The head end side of the box has ports for accommodating both the ventilation tubing and the anaesthesiologist's hands for managing the endotracheal tube and mask. The anaesthesiologist can even assist the surgeon, if required. The two sides of the box were designed to accommodate the surgeon's and assistant's hands. The port for the chief operating surgeon's dominant hand was made to a large size, to enhance the mobility of the surgeon's hands.
In addition to the ports for hands, smaller ports have been provided for cautery wiring and suction tubing. Additional suction tubing, connected to a high-efficiency particulate air filtrate unit, is accommodated through one of the ports, to provide a continuous negative-pressure environment. All the ports are sealed with silicone seals to reduce the risk of air escape.
The roof is composed of slanted panels, providing excellent vision from all viewing angles. All instruments (including the tracheostomy tube) are placed inside the box with a fresh pair of gloves prior to the procedure. The box is disinfected and sterilised with alcoholic solutions, or by fumigated with hydrogen peroxide prior to the procedure.
The box can be used for tracheostomy care and suctioning of the tracheostomy tube. Figure 1 shows the box and setup, demonstrated with the help of a manikin.
Fig. 1. Photographs showing the described protective box and setup.
Box utilisation for tracheostomy
We performed an open elective tracheostomy on a 36-year-old male for prolonged ventilation. Institutional ethical clearance was obtained prior to use of the box. Informed consent regarding the procedure and use of the box was obtained from the patient pre-operatively. All standard general precautions were taken during the procedure. The patient was paralysed throughout the surgery. Ventilation was withheld from the trachea stoma until the tracheostomy tube had been inserted.
Results
The procedure was performed completely within the box. The surgeon and assistant stood on either side of the box during the operation. All instruments required for the procedure and for intubation were also kept within the box, in case of an emergency. Fresh pairs of gloves were worn after inserting hands into the box, on all sides.
The entire procedure was performed within 20 minutes. No complications were noted during the procedure. Haemostasis was checked and secured. There was a minimal amount of discomfort noted by the surgeon and assistant, in terms of restricted hand movements during the procedure. The box, with its negative-pressure environment, was left over the patient for 2 hours, with continuous monitoring.
Discussion
As the box is made of rigid acrylic material, hand movements may be somewhat restricted. However, our first tracheostomy performed within the protective box was completed within 20 minutes. The hand movement restriction experienced was easily manageable.
The risk of surrounding contamination is expected to be much lower compared to previously described barrier enclosures. The base sheet helps to stabilise and seal the box at the base. The sealable ports and base sheet enforce the barrier enclosure and the negative-pressure environment.
The slanted roof panels provide adequate vision for the surgeon, assistant and anaesthesiologist. Continuous suctioning helped to prevent fogging within the box too.
We recommend use of this box during tracheostomies, in addition to existing recommendations. The box will be a useful adjunct in bedside tracheostomies too. We propose the use of this box for both open and percutaneous tracheostomies. The same box can be used for tracheostomy tube care, including tube changes.
The use of such barrier protection devices will also be beneficial in poor resource settings, as negative-pressure rooms and powered air-purifying respirators may not always be available.
As the device can be reused after appropriate disinfection and sterilisation, it is cost-effective. However, the device is yet to be validated for its efficacy and from an ergonomics perspective.
Acknowledgements
We wish to thank Mr N K Jain and the entire team of Iscon Surgicals (Jodhpur, Rajasthan, India) for transforming our idea into a reality by making the box.
Competing interests
None declared
