Aerosol Generating Procedures and Mask Use in Melbourne

Eric Levi MasksUPDATE BELOW. It happened again the other day. I asked for an N95 mask for my airway operating list. One hospital provided, another said no. Yes, pre-op swabs are negative, but we know that there is a false negative rate and I spend 3-4 hours in multiple patients’ nose, oral cavity, oropharynx, larynx and trachea in one session. The risk for aerosolization is high and I, as the surgeon standing 15-30cm away from the patient’s mouth, am exposed. The mask has become yet another symbol. Not a symbol of freedom or anything, but a symbol of value and trust. How much does a hospital trust your clinical judgement as a frontline clinician?

I am an ENT surgeon. That means I spend a majority of my time face to face in clinic examining patients and performing awake flexible nasoendoscopies. In addition, I spend hours in the operating theatre debriding, cauterising, incising, suturing, debulking and manipulating the airway mucosa. This is the very definition of Aerosol Generating Procedure. Studies show that the viral load is high in the nasal, nasopharynx, oropharynx and tracheal secretions, which all happen to be my daily operating sites. In sinus surgery, oropharyngeal surgery such as tonsillectomy and in bronchoscopies, I am getting splashbacks of patient secretions on to my face mask and face shield. A rigid bronchoscopy or laryngeal surgery is probably the highest risk of aerosolization. The airway is open. Positive pressure ventilation is applied, and the air return is direct from the laryngotracheal lumen on to the surgeon’s face. I am inhaling the air that is expelled from the patient.

In the US, UK and Canada, the Otolaryngology Head & Neck Surgery Societies recommend N95 for all AGPs (links below). In Australia the ASOHNS (Australian Society of Otolaryngology Head & Neck Surgery) on recommendation from the Office of the Federal Chief Medical Officer only recommends standard surgical face mask for AGP (link below). This was back in April when case numbers were low. Here we are now in August in the heart of Melbourne outbreak having thousands of positive covid cases and more than a thousand active Health Care Worker infection. As the community numbers go up, the hospital admissions go up a couple of weeks later and health care worker numbers also follow.

On top of that, there are concerningly more data about COVID19 being an “opportunistic airborne” pathogen (short of calling it a true airborne pathogen), and the published data on the number of ENT surgeons around the world who have caught COVID and many who have succumbed to the disease (See link below).

What about the negative preop swab, you say? Well, the test is not 100% foolproof. There is a known false negative rate. A positive test is helpful to confirm and contact trace. A negative test is not a complete reassurance. One illustrative case in that paper was about a patient who had a mastoidectomy done who had a negative preop covid test. Surgery went on with standard precautions (not N95). The patient developed covid symptoms a few days post op. The patient and the surgeon were then tested and found to be covid positive. Unfortunately the surgeon died as they had comorbidities. This is tragic. Another case is that of a tracheostomy where 3 surgeons and 5 nurses subsequently tested positive.

AGPs are truly high-risk procedures for the surgical and anaesthetic team, even if the patient is low risk. Here in Melbourne our COVID numbers are high and there will be many asymptomatic carriers. As our Premier has said, “This is a public health bushfire, but we cannot smell the smoke or see the fire.”

I am not asking for the protocol for the whole country to be changed. The risk of an AGP as an ENT in Melbourne is much higher as compared to an ENT in Perth, Brisbane or Auckland. I am simply pleading for hospitals to understand that when a surgeon request an N95 for the team (7 staff members, 7 masks for the whole theatre session – we can put a standard mask over it to save money), it’s not to be fancy or to overreact. It’s because there is a real tangible risk. I would like my team performing a high risk AGP to be as safe as possible. What applies to ENT, also applies to Maxillofacial surgery, Dental surgery and any other respiratory mucosal interventions. None of us like wearing the N95. It’s uncomfortable. But we do it because it keeps us safe.

Please don’t say the evidence for N95 use is not strong. What evidence do you need more? Infected health care workers numbers? It’s a small financial investment that would potentially safe a few health care workers from being sick or being furloughed. Not for everyone, just for the high risk activities on covid unknown or covid negative patients. Melbourne today is not where Australia was back in April. We are geographically high risk now for the next few weeks/months.

I know I’m not a clever Public Health or Infectious Disease Physician who can interpret all sorts of epidemiological data, graphs and modelling. I am just a foot soldier on the front lines in people’s noses and mouths every single day. I hope requesting a mask from a hospital will not be met with resistance “Because the protocol says no.” My team down the bottom of the ladder here just need to know that we are valued enough that even an N95 is worth giving to us. We just want to go home safely to our families.

References.

American Guidelines. https://www.entnet.org/sites/default/files/uploads/guidance_for_return_to_practice_part_one_update_070120.pdf

Canadian Guidelines. https://www.entcanada.org/wp-content/uploads/Protocol-for-COVID-and-AGMP-3-iw-mailer.pdf

UK Guidelines. https://www.entuk.org/sites/default/files/COVID%20BAOMS%20and%20ENT%202nd%20update%20FINAL.pdf

https://www.gov.uk/government/publications/covid-19-personal-protective-equipment-use-for-aerosol-generating-procedures

Australian Guidelines. http://www.asohns.org.au/about-us/news-and-announcements/latest-news?article=88

High-Risk Aerosol Generating Procedures in COVID-19: Respiratory Protective Equipment Considerations.  https://www.entnet.org/sites/default/files/uploads/howard_high-risk_aerosol_generating_procedures_in_covid-19_respiratory_protective.pdf

Aerosol-generating otolaryngology procedures and the need for enhanced PPE during the COVID-19 pandemic: a literature review. https://journalotohns.biomedcentral.com/articles/10.1186/s40463-020-00424-7

International Registry of Otolaryngologist ‐ Head and Neck Surgeons with COVID‐19. https://onlinelibrary.wiley.com/doi/10.1002/alr.22677

 UPDATE 12th August 2020.

As of Monday 10th August, the Australian Society of Otolaryngology Head & Neck Surgery have upgraded their advice in line with the Federal Health Department Recommendations. N95 for AGPs.

http://www.asohns.org.au/about-us/news-and-announcements/latest-news?article=93

https://www.health.gov.au/sites/default/files/documents/2020/08/coronavirus-covid-19-guidance-on-the-use-of-personal-protective-equipment-by-health-care-workers-in-areas-with-significant-community-transmission-coronavirus-covid-19-guidance-on-the-use-of-personal-protective-equipment-by_0.pdf

The Victorian DHHS so far has not changed their advice (No N95 for AGP, covid clinic or hotel quarantine staff).

https://www.dhhs.vic.gov.au/personal-protective-equipment-ppe-covid-19


Leave a Reply

Your email address will not be published. Required fields are marked *