Some medical procedures carry more risk of coronavirus transmission than others. Those that create aerosols top the list.

An aerosol is a suspension of fine solid or liquid particles in the air. Larger particles settle in a reasonably short distance and are referred to as droplets in the infection control context; however, smaller particles can travel as aerosols on air currents, remaining in the air for longer and distributing over a wide area.

Autopsy, airway suctioning, and cardiopulmonary resuscitation are among the medical procedures that pose a risk of spreading Covid-19 from a patient to their healthcare provider by creating aerosols, according to research published in the journal BMJ Open Respiratory Research.

A multi-disciplinary team, including occupational health, preventive medicine, and infectious disease specialists, reviewed public health guidelines, research papers, and policy documents in English and French to determine which procedures are classified as aerosol-generating.

“What we sought to do was to understand which procedures generate aerosols and therefore require a higher grade of personal protective equipment,” said University of Alberta medicine professor Sebastian Straube, who also heads the preventive medicine division of the faculty of medicine & dentistry. “Where there is 80% agreement from a number of different source documents, we are reasonably confident that, yes, the classification of these procedures as aerosol-generating is accurate.”

These are the procedures that are classified as aerosol-generating by 90% or more of the 128 documents reviewed:

• Airway suctioning

• Autopsy

• Bronchoscopy

• Breaking closed ventilation systems

• Cardiopulmonary resuscitation

• High-flow oxygen therapy

• High-frequency oscillatory ventilation

• Intubation and extubation procedures

• Manual ventilation

• Nebulized or aerosol therapy

• Non-invasive ventilation

• Sputum induction

• Surgery/postmortem procedures with high-speed devices

• Tracheostomy and tracheostomy procedures

Disagreements existed between sources on some procedure groups, including oral and dental procedures, upper gastrointestinal endoscopy, thoracic surgery and procedures, and nasopharyngeal and oropharyngeal swabbing. The researchers recommend that further exploration be done on this short list of procedures for which they found no consensus.

Straube said that healthcare workers who perform aerosol-generating procedures should wear filtering facepiece respirators, such as N-95 masks, along with other personal protective equipment such as gloves, gowns, and eye protection.