Helping tackle COVID-19 – preventing aerosol transmission and improving patient care

July 17th, 2020

The COVID-19 crisis has caused tremendous changes to our economy and way of life. In the healthcare sector, there is substantial concern about the transfer of the virus from infected patients to front-line healthcare workers. This anxiety is primarily concerned with the aerosolisation of the virus when a patient speaks, coughs, or when certain procedures that produce aerosols are used.

We have been involved in a collaborative project between the University of Melbourne, Western Health and the Royal Melbourne Hospital, to address these concerns. A ventilated “pram hood” was developed by the University of Melbourne which sits over the patient’s bed and creates a physical barrier between the patient and the healthcare worker, while still allowing easy patient access and filtering vented air. The filtered exhaust creates a negative pressure system, preventing virus-laden aerosols and droplets escaping to potentially infect healthcare workers or visitors. Video Provided courtesy of Bloomber QuickTack News.

Although our work doesn’t usually reside within the healthcare industry, our aerosol expertise and specialised instrumentation lent itself perfectly to verifying the performance of the hood, as well as understanding the production of aerosols from various procedures.

After thorough testing of the hood (see our initial tests using a smoke machine in the video below), we found it was more effective at preventing aerosol spread than the standard N95 protective masks that are used throughout the medical industry as primary PPE. This is great news, particularly because the hood was designed to be low cost, and is built locally with all local parts and suppliers.


Interestingly, some of the medical procedures which were of highest concern to the healthcare system were found to produce negligible aerosol – findings that are important given many of these procedures, which represent the best care for patients, have been cancelled because of the concern.

Another concern noted by medical professionals was the effects of power loss to the vacuum unit. Through the use of CO2 measuring devices we found that in the case of power loss there was enough passive ventilation to prevent CO2 from reaching unsafe levels. Particulate levels in the room remained low during power loss despite the loss of negative pressure. Rising humidity due to exhalation and some discomfort from a lack of freshness was observed, but this changed quickly after power was restored to the filter unit.

The entire process of hood development, verification and aerosol study occurred in record time – as is the case with anything COVID-19 related research at the moment.  From hood inception to publication took just two months! You can read our paper here.

It’s a new field for us, but we are looking forward to continuing to redirect our knowledge and expertise to helping the fight against COVID-19.

Written by: Ruhi Humphries, Melita Keywood, Christopher Roulston.