key: cord-0691359-ve7qbzhw
authors: Baerlocher, Mark O.; Baerlocher, Felix J.
title: Overuse/Abuse of the definition of ‘Aerosol Generating Procedures’ to limit mask use.
date: 2020-04-27
journal: J Vasc Interv Radiol
DOI: 10.1016/j.jvir.2020.04.016
sha: c8078a1e171835387f2d72c9a62f3bab74f4462d
doc_id: 691359
cord_uid: ve7qbzhw

nan

The concept of aerosol generating procedures or aerosol generating medical procedures (AGPs or AGMPs) was developed by the World Health Organization and the Centers for Disease Control and Prevention (CDC) in the wake of the Ebola outbreaks. 1 An AGP is defined as any medical procedure that can induce the production of aerosols of various sizes, including small (<5 micrometers) particles. 2 The implication is that aerosols are associated with a greater risk of transmission to others, including healthcare workers (HCWs).

The original list of AGPs by the WHO included intubation and extubation, manual ventilation, open suctioning, cardiopulmonary resuscitation, bronchoscopy, surgery and post-mortem procedures involving high-speed devices, some dental procedures (e.g. drilling), non-invasive ventilation such as Bi-level Positive Airway Pressure (BiPAP) and Continuous Positive Airway Pressure ventilation (CPAP), High Frequency Oscillating Ventilation (HFOV), and induction of sputum. 3 A subsequent meta-analysis sought to determine the published evidence of transmission of acute respiratory infections to HCWs from patients undergoing AGPs compared to the risk from patients not undergoing AGPs. 4 A total 5 case-control and 5 retrospective cohort studies were included which evaluated transmission of SARS to HCWs. A limited number of procedures were evaluated, and even among those that were, a GRADE analysis determined that the evidence was of 'very low quality'. Nonetheless, after the meta-analysis by Tran et al (2012) , the WHO updated their list to only include tracheal intubation, tracheotomy, non-invasive ventilation, and manual ventilation, as there was only consistent evidence for the more limited list of procedures. 3

The majority of medical procedures have not been studied in terms of aerosol generation and of the few that have the evidence is of very low quality. This has been acknowledged by the WHO, 3 implying that their list may be incomplete. The CDC has also noted that their list may be incomplete, as "…there are limited data available to definitely define a list of AGPs…'. 1 Other governmental groups, including NHS Scotland, have made it clear that due to the '…extremely limited volume and quality of studies available this hierarchy should be used for academic purposes only and not for clinical decision making.' 3

In order to fill the gap, specialty associations and societies have published guidelines defining which of their procedures should be included as AGPs. For example, in Interventional Radiology, lung biopsies and G-tubes are thought to increase the risk of generating aerosols. [5] [6] [7] Although the aerosol generating capability of these procedures has not been adequately studied directly, these procedures have an increased likelihood of causing heavy coughing in patients. The generation of aerosols from coughing has been studied and established. 8 Other specialty societies have produced similar statements, claiming that some of the procedures within their domain should likewise be considered AGPs. 9, 10 Which specific procedures are included on the list of AGPs is important, as it is agreed that HCWs should wear N95 filtering-facepiece respirators (or a higher level respirator) when there is a known risk of airborne disease transmission. 11

There is currently a broadly reported, worldwide shortage of Personal Protective Equipment (PPE) due to the rapidly expanding COVID-19 pandemic. 12 The US government's emergency stockpile of PPE is nearly exhausted. 13 Hospitals are urgently creating PPE drives, desperately looking to community businesses, dentists, industrial workers, painters, carpenters, and others for donating goggles, facemasks, and gowns to hospitals. 14 Individual doctors, nurses and other HCWs are turning to unconventional sources such as Amazon or Walmart. Many ideas for mitigating the shortage have been suggested in numerous fora. 15 

As part of the strategy to conserve PPE supplies, and N95 masks in particular, various guidelines are quickly being created about conditions where various levels of PPE should be used. This can create a serious problem when the poorly supported historical WHO/CDC definition of AGPs is used in a definitive sense, and dissenting statements published by various specialty societies are ignored.

For example, guidelines published by Public Health Ontario, a government group, state that airborne precautions (e.g. N95 masks) should be used when AGPs are performed on patients with suspected or confirmed COVID-19; while only droplet and contact precautions are recommended otherwise. 16 These guidelines are then being used by some hospitals as 'mandatory' in e-mail blasts to all staff. Should staff point out that the CDC/WHO definition of AGPs is incomplete, they may still be prohibited from using N95 masks in procedures that their respective specialty societies do consider as AGPs.

Unsurprisingly, there is a battle brewing between frontline HCWs and those attempting to limit PPE usage. Various groups representing HCWs have come out with statements supporting that individual HCWs should have access to the level of PPE that they believe, in their expert opinion, after a point-of-care assessment, is necessary for a given patient encounter. 17 

The purpose of this Commentary is not to question whether COVID-19 is airborne, as this remains hotly debated and is, as of now unclear.

Rather, we wish to expose the overuse or abuse of the incomplete definition of AGPs as a means by which to provide cover for the shortage of PPE. Both CDC and WHO seem to have recognized that their AGP list may be incomplete, and critical reviews have stated that the quality of evidence for what is included is 'very low'. Hospitals or other provider organizations should not take a hardline stance based on an incomplete definition of AGPs to the point of prohibiting use of certain masks/PPE. Latitude should be afforded to HCWs to use their own clinical judgement, particularly when supported by specialty expert consensus panels. We must learn from the prior SARS experience and error on the side of caution. We must also trust the judgement of HCWs. We are trusting them with patients' lives, why not trust them with evaluating which tools and what safety precautions they need?

If the shortage of PPE, including N95 masks, is the true cause of hospitals and other provider organizations attempting to clamp down on usage, this should be admitted up front, rather than hiding behind incomplete and poorly supported definitions. At that point, HCWs will have decisions of their own to make, if their employer is unable to adequately guarantee their safety. 18 Finally, even if it turns out that COVID-19 cannot be aerosolized, the next pandemic virus may well be, we may again run out of PPE, and encounter hospitals and other provider organizations trotting out the same potentially incomplete list of AGPs as gospel.

Infection prevention and control during health care for probable or confirmed cases of novel coronavirus (nCoV) infection. World Health Organization

Aerosol Generating Procedures and Risk of Transmission of Acute Respiratory Infections to Healthcare Workers: A Systematic Review

Aerosol Generating Procedures Performed by Interventional Radiology Clinical Notification from the Society of Interventional Radiology

Checklist for preparing your IR service for COVID-19. Cardiovascular and Interventional Radiological Society of Europe

The Canadian Association for Interventional Radiology (CAIR) and Canadian Association of Radiologists (CAR) Guidelines for Interventional Radiology Procedures for the Patients with Suspected or Confirmed COVID-19. Canadian Association for Interventional Radiology (CAIR) and Canadian Association of Radiologists (CAR) Guidelines for Interventional Radiology

Dispersion and Exposure to a Cough-Generated Aerosol in a Simulated Medical Examination Room

COVID-19: Advice from the Canadian Association of Gastroenterology for Endoscopy Facilities

Position Statement on gastrointestinal endoscopy and the COVID-19 pandemic

Guideline for isolation precautions: Preventing transmission of infectious agents in health care settings

Health care workers on frontlines feel like 'lambs to the slaughterhouse

Protective gear in national stockpile is nearly depleted, DHS officials say. The Washington Post

The Race to Keep Health Care Workers Protected From Covid-19

Sourcing Personal Protective Equipment During the COVID-19 Pandemic

TECHNICAL BRIEF: Updated IPAC Recommendations for Use of Personal Protective Equipment for Care of Individuals with Suspect or Confirmed COVID-19

Joint Statement: COVID-19 and Health and Safety Measures, including Personal Protective Equipment. Ontario Nurses' Association, Chief Medical Officer of Health (Ontario), Ministry of Health (Ontario

Canadian nurses treating COVID-19 patients cite unsafe-work laws to demand N95 masks