The nasolaryngoscopic hood effectively reduces aerosol exposure to patients

The COVID-19 pandemic continued to cause dramatic shifts in the practice of otolaryngology. Even with standard precautions, such as physical removal and wearing of personal protective equipment, aerosol-generating procedures such as nasolaryngoscopy (a common procedure in the office where a soft, flexible range of fibers passes through the nose and throat) and intranasal instrumentation have been found to carry risk potential transmission if not adequately protected.

In an attempt to mitigate exposure to these particles in the air, researchers at Boston University School of Medicine (BUSM) designed and tested a prototype hood for nasolaryngoscopy, worn by a patient that offers safe and effective protection in reducing aerosol exposure.

To examine the efficiency of the hood, a particle counter was used to calculate the average particle number of 0.3 mm / L detected during various clinical scenarios that included sneezing, nasolaryngoscopy, sneezing during nasolaryngoscopy, and topical lidocaine spraying. The experiments were repeated to compare the efficiency of the hood against any protection.

When the patient’s barrier (hood or mask) was not used, a significant increase in aerosol was observed during sneezing, sneezing during nasolaryngoscopy, and topical spraying. With the hood installed, the aerosol level returned to the initial level in each scenario.

This simple intervention allows patients to undergo routine flexible nasal laryngoscopy, even with topical administration of lidocaine spray, with less risk to the donor. If a patient starts sneezing during an examination, our data suggests that service providers will remain protected by using a hood. “

Christopher Brook, Ph.D. Med., Corresponding author, Assistant Professor of Otolaryngology – Head and Neck Surgery, BUSM

Although this study evaluated the effectiveness of the hood in setting up routine nasolaryngoscopy in reducing aerosol proliferation, there are other possible applications, but also one major obstacle to be overcome. “For clinical use, the hood should be mass-produced to allow single use, or a safe and effective protocol should be established for cleaning and reusing each hood,” said Brook, who is also an otolaryngologist at Boston Medical Center.

These findings appear online in the journal Otolaryngology – Head and neck surgery.


Boston University School of Medicine

Journal reference:

Plocienniczak, MJ, and others. (2020) Evaluation of a hood prototype for nasolaryngoscopy during aerosol generation procedures in otolaryngology. Otolaryngology – Head and neck surgery.