COVID-19 Information for Anesthesia Providers
After seeing images of healthcare workers in China and, more recently, South Korea wearing Ebola-like personal protective equipment (PPE) when caring for patients infected with SARS-CoV-2, our group became increasingly concerned about appropriate PPE for providers involved in aerosol-generating procedures. Although there is an increasing appreciation of the risk of nosocomial viral transmission and aerosol-generating procedures, more information is needed to better understand this association (Judson SD & Munster VJ, 2019, Tellier R, et al, 2019, and Fernstorm A & Goldblatt M, 2013). We know from SARS experience in Toronto, that providers participating in the aerosol-generating procedures such as intubations were 13 times more likely to get infected than other healthcare workers (Kamming D et al., 2003). A video from Xinhua News Agency (New China News Agency) shows a team of anesthesiologists donning Ebola-like PPE when performing intubations.
The research letter in the New England Journal of Medicine indicates that SARS-CoV-2 transmission modes include aerosol and fomite transmission:
“Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed)."
Experimental Aerosol and Surface Viability
Aerosol: 3 hours
Copper: 4 hours
Cardboard: 24 hours
Plastic & Steel: 3 days
A report from the University of Nebraska Medical Center on the pre-printer server medRxiv, a brief report from NIH Laboratory of Chemical Physics and CDC Morbidity and Mortality Weekly Report provides additional evidence for aerosol transmission of SARS-CoV-2 and further supports airborne precautions.
There is evidence that asymptomatic individuals and individuals with mild symptoms have high viral loads in the upper respiratory tract early on unlike SARS-CoV (study in the pre-printer server medRxiv, research letter in the New England Journal of Medicine, and another study in the Science Magazine).
COVID-19 Anesthesia Care Recommendations
Canadian Journal of Anesthesia published the most comprehensive recommendations on COVID-19 for anesthesia and critical care providers based on the SARS experience, which we would encourage everyone involved in aerosol-generating procedures to review and implement similar protection measures in their practice when dealing with COVID-19 patients.
Personal Protective Equipment
CDC website has a series of videos describing proper PPE donning and doffing procedures.
Based on the small simulation study, a lower number of healthcare providers wearing PAPR system experienced contamination but had a higher number of donning and doffing protocol violations.
In the case of limited or exhausted N95 respirators supplies, please refer to the CDC and FDA recommendations:
Standard Respiratory Precautions
Converting operating room positive pressure environment into a negative pressure environment as noted in the above protocol is strongly recommended to prevent the possibility of airborne spread of SARS-CoV-2 virus out of the operating room and into the adjacent areas such as hallways and central core (Chow TT, et al, 2006, and Park J, et al, 2020). If the negative pressure environment is not possible then the positive pressure ventilation should be turned off.
Surfaces and equipment in the operating room should be cleaned with 62-71% alcohol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite (Kampf G, et al, 2020). However, certain equipment (such as anesthesia machines, anesthesia carts, computer keyboards, ultrasound machines) may be difficult to decontaminate after performing a procedure on COVID-19 patient. As suggested by Wong et al. in their review of operating room COVID-19 outbreak response measures in a large tertiary hospital in Singapore, high touch surfaces should be covered by plastic covers (see image below). There is some evidence that anesthesia machine covers (such as the ones made by Anesthesia Hygiene) reduce the contamination of the anesthesia machines (Biddle CJ, et al, 2018).
Some equipment such as the anesthesia cart cannot be covered. Anesthesia providers should consider either having a dedicated anesthesia cart for COVID-19 patients or a “case pack” with necessary drugs and single-use airway equipment that can be discarded after the procedure. Specialized procedure kits for peripheral IV, arterial line, central line, and regional anesthesia should also be considered.
Some of the non-pharmaceutical interventions include good hand hygiene and avoid touching one's face.
Personal hand hygiene devices with built-in reminders such as this prototype from Blink Device Company may be available in the near future for the use by healthcare providers.
There is growing evidence to support the utility of wearing masks around other people. Based on experimental evidence described from Nature Medicine Brief Communication, surgical masks could prevent transmission from symptomatic individuals: "Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets."
We may be also underestimating the ability of SARS-CoV-2 to spread by aerosol transmission. JAMA Insights brief report indicates that the sneeze can create a multiphase turbulent gas cloud (containing aerosol) that can travel up to 23-27 feet (7-8 meters). The author also suggests that we need to reconsider our classification of respiratory disease transmission into a droplet and airborne transmission and adopt a new model of a continuum of droplet sizes during respiratory emissions such as exhalation, cough and sneeze.
Practice social distancing since it does make a difference by flattening the epidemic curve. The examples of St. Louis and Philadelphia peak mortality during the 1918 influenza pandemic were illustrated in the article by Hatchett et al. A comment in Lancet discusses the transmission modeling for COVID-19 with and without social distancing. These non-pharmaceutical interventions have the potential to preserve healthcare resources. For projections of global COVID-19 impact refer to the Imperial College London reports. For current U.S. and state-by-state COVID projections refer to the COVID-19 Projections website. Our World in Data has an outstanding COVID-19 section with up-to-date statistics.
We, as anesthesia providers, must remain vigilant in the current era of emerging and re-emerging viruses such as Ebola, SARS, MERS, and SARS-CoV-2. As providers involved in aerosol-generating procedures, we must continue to prepare for and practice infection control procedures, which can minimize nosocomial viral transmission. As the New York Times opinion piece "We Knew Disease X Was Coming. It’s Here Now" suggests, we will be faced with other pandemics and, therefore, cannot be caught off guard.