Reducing the viral load while securing the airway

Many anesthesiologists have succumbed to the deadly COVID-19 virus. High mortality in Anesthesiologists is related to high viral load exposure during laryngoscopy and intubation. Despite the use of Personal Protective Equipment (PPE), anesthesiologists face a reasonable threat of virus exposure. With the possibility of the pandemic ebbing soon, elective surgery will restart. However, the threat of the virus will remain and thus we need to formulate methods to restrict aerosol exposure of anesthesiologists.

Many unconventional methods to reduce aerosol exposure, while securing the airway, have been recently described in social media. The methods described include the use of transparent plastic screens; intubation boxes; a plastic cover over the patient head-end, with the face mask and endotracheal tube kept under the sheet; use of video laryngoscope; stopping fresh gas flow during disconnect and laryngoscopy; avoiding general anesthesia as a technique.[1] We need to continue these precautions even after the epidemic recedes.

COVID-19 is an RNA virus with a lipid envelope. Disinfectants like chlorhexidine and alcohol can compromise this lipid envelope of enveloped viruses.[2] Damage to the lipid envelope compromises the integrity of the virus and neutralizes its infectivity. Detergents also damage the lipid envelope integrity. Most microorganisms expelled by COVID-positive patients reside in the upper airway. Ensuring oral hygiene helps reduce the microbial load. Toothpaste has detergent and so tooth brushing just before surgery will reduce the infectivity of the virus.

Chlorhexidine is the most widely used biocide in hand-washing and oral hygiene products.[2] Preoperative chlorhexidine mouthwash reduces the incidence of ventilator-associated pneumonia, and its use recommended.[3] Although chlorhexidine is not an active antiviral agent, it acts on lipid-enveloped viruses.[4] Chlorhexidine, in a 7% alcohol base, is used as a mouthwash routinely. Combinations of bactericidal/odor suppression chemicals, in up to 26% alcohol, are also used as a mouthwash. Although use of 60 to 90% of alcohol is considered optimal for antimicrobial efficacy, a combination of alcohol with chlorhexidine should reduce the oropharyngeal viral load. Patients should undertake a mouthwash and gargle with an oral hygiene product just before wheeling into the operating room.

Traditionally, oral hygiene is performed in the ward before shifting the patient for surgery. There is therefore a long time interval between it and tracheal intubation. If oral hygiene is performed just before surgery, the microbial load will be much lower. The reduction in viral load will benefit the patient by hindering the progress of the virus to the lower respiratory tract. It will also reduce the potential exposure risk of the intubating anesthesiologist. Guidelines from China do not recommend chlorhexidine rinse before surgery as it is not considered efficient against COVID.[5] Even though there is currently no scientific evidence, and if one presumes a low efficacy of oral hygiene methods, the use of this easy, low-cost, and benign preoperative oral hygiene strategy is recommended.[6]

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