key: cord-1044669-yk574m99
authors: Kumar, Sathish; Kapoor, Lalit; Barman, Dhiraj; Narayan, Pradeep
title: Aerosol‐mediated transmission of SARS‐Cov‐2 or COVID‐19 in the cardiac surgical operating room
date: 2020-07-11
journal: J Card Surg
DOI: 10.1111/jocs.14728
sha: ae8412e6f61a1f8ef8247c18ba70883532c91eae
doc_id: 1044669
cord_uid: yk574m99

nan

the heater-cooler units used in cardiopulmonary bypass circuits. 3 Thus, the risk of aerosol-mediated transmission is very real and the need for safety measures is extremely practical.

The coronavirus disease-2019 (COVID-19) virus spreads predominantly through droplet and aerosol routes and blood-borne infection is not considered a major source of transmission. 4 There are some major differences between droplet and airborne transmission that leads to airborne transmission in the operating room (OR) more of a hazard than the droplet route.

Based on electron microscopy, the size of the coronavirusshaped spherical particles is estimated to be about 0.125 μm (125 nm) and ranges from 0.06 to 0.14 μm. 5 While droplet infections are via larger respiratory particles, generally above 5 µm diameter, and are subject to gravitational forces, aerosol-mediated transmission occurs with smaller respiratory particles (generally <5 µm) circulating in the air. As a result, while contact is necessary for droplet infections and thereby handwashing and gloves are highly effective against contact transmission, viral particles transmitted though aerosol is absorbed via the respiratory mucosa and potentially across the conjunctivae, other measures are required to prevent transmission. These smaller viral particles (<10 µm) are most likely to penetrate deep into the lung and cause infection. 6 The radius of spread is also different and is no more than 1 m for droplet infections. However, because of the smaller size, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or COVID-19 as it is popularly known as, can spread across larger areas and has been shown to remain viable in aerosols even at 3 hours. 7 The highest viral load of the virus causing COVID-19 is in sputum and upper airway secretions and endotracheal intubation is the commonest and most relevant aerosol-generating procedure in cardiac surgery. 8 Apart from intubation and extubation, bag mask ventilation, suctioning of airways, insertion of chest drains, and thoracotomies can all lead to aerosol generation. 9 In pediatric cardiac surgery, valve repairs and at times in coronary artery bypass operations as well, transesophageal echocardiography (TEE) is often used. TEE carries an increased risk of transmission of SARS-CoV-2. While this risk is greater in nonintubated patients, viral transmission may still occur through direct contact with the patient's secretions, resulting in contaminated hands and surfaces with the potential to infect not just the echocardiographers but also other personnel in the OR. 10 Sternotomy requires a high-speed device and is considered to be a procedure that leads to blood and tissue fluid aerosolization. 4 Surgical smoke produced by heat-generating devices in cardiac surgery can also contain chemicals, blood and tissue particles, bacteria, and viruses. 11 A summary of aerosol-generating procedures is summarized in Table 1 .

Carbon dioxide (CO 2 ) insufflation in the operative field is prac- 

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