Debunking PPE myths with Dr. Jeff Powis: Which masks should health care workers wear during COVID-19?


Today, we continue our focus on PPE and proper usage. We appreciate the following article and video prepared by Dr. Jeff Powis, chief of infection prevention and control at Michael Garron Hospital. I also want to comment on how impressed we are with his expertise, commitment and dedication to staff and patients wellbeing.   

Dr. Jeff Powis used a black light to demonstrate the potential self-contamination risks when donning and doffing a surgical earloop mask and a mask with horizontal straps (N95 mask). Results found that self-contamination was higher with the use of an N95 mask.

When it comes to the use of personal protective equipment (PPE), Dr. Jeff Powis has one goal in mind: Do whatever it takes to keep health care workers and patients safe.

While PPE has always been a cornerstone of health care worker safety, it’s never been more critical, in higher demand, or publicly debated than during the COVID-19 pandemic.

One of the most widely deliberated PPE topics across the health care system continues to be around the appropriate use of masks, more specifically, when to wear a surgical mask with ear loops versus an N95 mask.

Both surgical earloop masks and N95 masks filter small particles (between 0.1 and 0.3 microns) at greater than 95 per cent efficiency. N95 masks have a tight seal with the healthcare worker’s face and are the preferred mask when performing aerosol-generating medical procedures (AGMPs). Aerosols are small enough that they float freely in the air, and as a result a tight seal is required to keep them out.

Surgical earloop and N95
Surgical earloop mask (left) and mask with horizontal straps (N95 mask) (right).

The great debate: Which masks should health care workers wear during COVID-19?

According to Dr. Powis, it is clear that COVID-19 is transmitted through droplets; it is not an airborne illness. As a result, droplet/contact precautions (earloop mask, face shield, gown and gloves) are the best way to keep health care workers safe when providing routine care for individuals with suspected or confirmed COVID-19.

An N95 mask is required when AGMPs are performed on patients with suspected or confirmed COVID-19, for example during tracheotomy, intubation and noninvasive positive-pressure ventilation, to name a few. Ontario hospitals have guidance and access to the full list of AGMPs from Ontario Health.

Often the greatest risk to healthcare workers is related to self-contamination at the time of doffing their PPE.

“After watching people don and doff their N95 masks, I noticed that people struggle with the horizontal straps so I thought I would test the theory,” says Dr. Powis.

In this short video, Dr. Powis used a black light to demonstrate the potential self-contamination risks between donning and doffing an earloop surgical mask and mask with horizontal straps (such as an N95).

“What we found is that earloop masks are easier to doff in comparison to a mask with horizontal straps. Masks with horizontal straps can actually predispose the user to self-contamination,” says Dr. Powis.

According to Dr. Isaac Bogoch, an infectious disease expert at University Health Network (UHN), “Human factors research provides a pragmatic window to real-world issues. In this case, there may be greater risk of self-contamination while donning and doffing N95 masks compared to surgical masks, based on their strap design.”

“Policymakers and front-line healthcare workers should consider these findings when choosing to use and re-use personal protective equipment,” says Dr. Bogoch.

Healthcare workers need to do a point-of-care risk assessment (PCRA) to ensure they make the right decision regarding their use of masks.  This video demonstrates that the risk of self-contamination is likely greater with an N95 mask.

“When choosing a mask it’s important to choose the right one for the job,” according to Dr. Powis.

“There are times when you need an N95 mask, but using one for routine patient care when it’s not necessary won’t make you safer, it paradoxically may increase your risk.”