COVID-19: A Novel Mask Design to Protect Health Care Workers and Prevent Aerosolization from Patients

Introduction: The COVID-19 pandemic dramatically impacted the health care system. It necessitated extensive use of personal protective equipment (PPE) by health care workers which rapidly became in short supply. We previously described a novel negative airway pressure respirator and a cadaveric model to evaluate the escape of aerosolized particles. We now present a novel personal protective mask that can be made out of components readily available at most hospitals in times of shortage.

Methods: A prototype mask (N-99) was designed by connecting an in-line anesthesia circuit HEPA N-99 filter to a standard Ambu mask. The mask is fixed to the user's face using adjustable rubber straps. To demonstrate the protective efficacy, the mask was fit tested on 10 healthy participants using standard sugar hood technique ([Fig. 1]). Our recently published cadaveric model was used to assess the escape of particles from the novel mask. Our model utilizes white colored smoke to simulate the SARS-CoV-2 virus and a high-definition camera to capture the smoke particles on a black background. The N-99 mask, with and without the filter, was compared with no mask, a standard surgical mask, and a commercially available N-95 mask.

Results: The hood fit test was successful in every volunteer demonstrating good fit and protection. All the participants also described the N-99 mask as more comfortable, than a traditional N-95. The cadaveric model revealed that the novel N-99 mask was able to block 98% ([Fig. 2]) of the particles whereas the other masks were less effective ([Fig. 3]).

Discussion: We present a novel N-99 mask made with readily available hospital supplies. Based upon our cadaveric model, the N-99 mask seems more effective at filtering submicron particles better than a standard N-95 mask. The N-99 mask could also be applied to a patient suspected of being infected to prevent virus spreading while other measures are put in place. Future directions include refining the design to further increase the comfort and adapt the filter to our previously described NAPR mask.

Fig. 1 Fit test setting of the new mask.

Fig. 2 Processed image N-99.

Fig. 3 Processed image surgical mask.

Publication History

Article published online:
12 February 2021