Fluorescein Markers for Droplet Spread
We used fluorescein dye and ultraviolet (UV) light to assess the efficacy of the negative pressure housing system in minimizing aerosol dispersion. Droplet formation and patient secretion spread was evaluated with the application of fluorescein into the nasal cavity.  We diluted fluorescein (Fluorescite, fluorescein injection USP, 10% at 100mg/ml; Alcon Laboratories; Fort Worth, TX) to a concentration of 1% fluorescein in 10ml of normal saline solution and topically applied dropwise to the nasal cavity and nasopharynx at the beginning of the case. This was further diluted with saline during the case. The fluorescein solution washes away easily with saline irrigation, so regular reapplication of fluorescein dye was performed the nasal cavity prior to use of instruments like the microdebrider, bipolar and monopolar cautery and high-speed drilling. At the conclusion of the surgery, an evaluation of the surgical drapes and gowns was performed using an ultraviolet Wood’s lamp.
We did not have a control group because routine preoperative SARS-CoV-2 testing is not being performed at our institution at this time. As such, a universal personal protective equipment (PPE) policy was applied for all aerosol generating surgeries, including endoscopic endonasal and endo-oral surgery, consisting of an N95 mask or powered air-purifying respirator (PAPR), eye protection, and fluid resistant gown.