Technical Description:
Our technique aims to utilise resources readily available within the healthcare service to construct an easy to use adjunct mask to aid safer FNE. Our device incorporates a standard anaesthetic air cushion face mask, double swivel elbow adapter and a viral filter. In addition, a paediatric mask may be utilised to safely assess for neck stoma patency/ pathology.
Whilst the patient is being examined, the mask is applied and secured with an elasticated band. The soft cushion of the mask conforms to facial contours, creating a comfortable, soft, low-pressure seal around the nose and mouth serving as an additional barrier. The mask comes in a range of appropriate sizes, the transparent structure providing a clear view of the nasal and oral cavities. Masks possess a standard 22F port, onto which a double swivel elbow adapter with an in-built 7.6mm sealed bronchoscope port (figure 1) is attached. We found the Intersurgicalī›š swivel adaptors best suited for purpose due to their ability to directly attach to the mask, reducing the need for numerous additional components. A viral filter is connected to the second port of the swivel elbow connector (figure 1), allowing respiration, whilst filtering exhaled air to avoid viral transmission. All the 3 components are single-use, and are assembled as a single unit, to form the PPEM (figure 2), which is provided to the patient to don prior to examination (figure 2). Once the patient is comfortable, the sealable bronchoscope port cap is opened, and the FNE is passed through under direct guidance using an appropriate endoscopic camera stack system (figure 3). At this point the mask can be adjusted slightly to allow for appropriate trajectory of the nasoendoscope into the nasal cavity. Any droplets or aerosol generated is contained within the face mask, with the only potential escape points being circumferentially around the FNE entry port site. Having completed the procedure, the nasoendoscope is slowly withdrawn and sent for decontamination, and the bronchoscope port closed. The patient is then advised to retain the mask until having left the room, where it can be disposed of as clinical waste.
In an attempt to estimate aerosol risk reduction using our device, we implemented the use of Betadine solution in a spray applicator (figure 4). The FNE was passed through a tight aperture through a sheet of paper and then passed through the mask as per normal procedure (figure 5). Four sprays were then directed into the mask to simulate aerosol generation, whilst the paper was held an inch away from the bronchoscope port to detect any potential leakage. This process was repeated without the use of a mask, spraying directly onto a sheet of paper from an equal distance to compare the relative reduction of aerosol to the clinician (figure 6). The PPEM demonstrated a significant reduction in potential aerosol exposure to the examiner.