Comparing the user seal check and fit test between two types of N95 respirators - the Halyard N95 Particulate Filter Respirators and the ProShield® N-95 masks

INTERVENTION: We will perform a user seal check and a quantitative fit testing of N95 masks on a total of 80 of the anaesthetic staff members. Before the commencement of the study, all participants will have received a formal personal protective equipment (PPE) training session, which includes N95 masks donning/doffing technique and user seal check method. They will also watch a video demonstration on fit testing procedure. Two types of N95 masks are selected for this project: 1) Halyard N95 Particulate Filter Respirators, and 2) ProShield® N‐95 masks. Each participant will fit check and fit test both brands of the masks. The order of the N95 mask brand to be examined is randomly allocated. The participant will don the first probed and randomised mask, and perform a user seal check in front of a mirror. A negative result means the wearer could not detect any gross leakage and will then proceed to the quantitative fit test with that mask. The quantitative fit test involves the use of the Portacount machine, which will be calibrated at the beginning of each testing day, using a provided HEPA filter. The subject will attach their mask probe to the PortaCount machine via plastic tubing that has been soaked in 99.5% isopropyl alcohol solution. The test will then begin according to the United States Occupational Safety and Health Administration protocols (https://www.osha.gov/laws‐regs/federalregister/2019‐09‐26), which consists of 4 exercises: 1) Bending over at the hips and returning to upright repeatedly, taking two breaths when bent over. This lasts 50 seconds. 2) Reading a standardized text aloud for 30 seconds 3) Moving the head from side to side for 30 seconds 4) Flexing and extending the neck for 39 seconds The test will be observed throug CONDITION: Airborne transmitted disease;COVID‐19; ; Airborne transmitted disease ; COVID‐19 Infection ‐ Other infectious diseases Respiratory ‐ Other respiratory disorders / diseases PRIMARY OUTCOME: Fit test result ‐ pass or fail.; Pass is defined as a fit factor of >100. The fit factor is calculated by dividing the concentration of the particles in ambient air outside the mask by that inside the mask. ; It is assessed by a trained personnel using the PortaCount machine, which will be calibrated at the beginning of each testing day, using a provided HEPA filter. The subject will attach their mask probe to the PortaCount machine via plastic tubing that has been soaked in 99.5% isopropyl alcohol solution. The test will be performed according to United States Occupational Safety and Health Administration protocols (https://www.osha.gov/laws‐regs/federalregister/2019‐09‐26).[At the time of fit testing ] SECONDARY OUTCOME: Comparing the accuracy of fit check with fit test results. ; The accuracy of the user seal check will be scored against the fit factor. A fit factor of > 100 is considered a pass. The accuracy will be expressed as sensitivity=true positive/(true positive + false negative) and specificity=true negative/(true negative + false positive). ; The fit check is assessed by user seal check technique as described by the manufacturer's user guide. The fit testing is assessed by using Portacount machine. The test will be performed according to United States Occupational Safety and Health Administration protocols (https://www.osha.gov/laws‐regs/federalregister/2019‐09‐26).[At the time of fit check and fit test.] Fit check result ‐ positive is when there is a leak, negative is when there is no leak detected. ; INCLUSION CRITERIA: Anaesthetic staff members, including anaesthetic consultants and trainees who is currently working in the Royal Melbourne Hospital ; To User Seal Check a respirator, the wearer should forcefully inhale and exhale several times. The respirator should collapse slightly upon inhaling and expand upon exhaling. The wearer should not feel any air leaking between his/her face and the respirator. This is the sign of a good facial fit and a successful User Seal Check.[At the time of fit checking] Fit test score ‐ as measured by fit factor. The fit factor is calculated by dividing the concentration of the particles in ambient air outside the mask by that inside the mask. ; It is assessed by a trained personnel using the PortaCount machine, which will be calibrated at the beginning of each testing day, using a provided HEPA filter. The subject will attach their mask probe to the PortaCount machine via plastic tubing that has been soaked in 99.5% isopropyl alcohol solution. The test will be performed according to United States Occupational Safety and Health Administration protocols (https://www.osha.gov/laws‐regs/federalregister/2019‐09‐26).[At the time of fit testing]