New applications of a portable isolation hood for use in several settings and as a clean hood.

Nishimura, Hidekazu; Fan, Yuxuan; Sakata, Soichiro

Background We previously reported that we developed a compact and portable isolation hood that covers the top half of a patient sitting or lying in bed. The negative pressure inside the hood is generated by a fan-filter-unit (FFU) through which infectious aerosols from a patient are filtered. The outside area is kept clean which decreases the risk of nosocomial infections in hospital wards. We tried new applications of the hood. Methods The negative pressure hood was newly applied in an intensive care unit (ICU) as a place where a staff performs the practice of suctioning that generates much aerosol from the patient, as well as a waiting space for patients. Furthermore, the possibility that the hood can be converted to a positive pressure hood as a clean hood by switching the airflow direction of FFU was assessed. The cleaning efficacy of the inside of the hood was tested using an aerosolized cultured influenza virus tracer and an optimal airflow rate was determined according to the test results. Results The hood, named Barrihood, was found to be competent to be used (I) for tracheal suctioning in ICU, (II) as a waiting space for a child in a nursery who suddenly showed symptoms of the disease and waiting to be picked-up by the guardian, and (III) as a waiting space in a special outpatient clinic in a hospital for COVID-19 suspected cases to prevent dissemination of airborne pathogens. The positive pressure hood was also competent in keeping clean air quality that meets the standard class 100 of NASA's bio-clean room category. Conclusions The proposed new applications will broaden the range of the hood's usage. The isolation hood could be useful in many settings to protect people outside the hood from a patient inside, or to protect an individual inside from air particles outside the hood, such as airborne pathogens, allergens, or hazardous particulate matter like PM2.5.