Aerosol-Generating Procedures (AGPs) are medical and dental interventions that create a heightened risk of infectious disease transmission by producing fine, airborne particles. These procedures actively generate aerosols, which can remain suspended in the air for extended periods and travel considerable distances from the patient. The primary purpose of controlling these activities is the prevention of airborne infectious disease spread, particularly protecting healthcare personnel and other patients. Establishing strict protocols around AGPs is a fundamental component of infection prevention and control in clinical settings, ensuring that high-risk procedures can be performed safely.
Defining Aerosol-Generating Procedures
Procedures classified as AGPs are those that forcibly expel material from the patient’s respiratory tract, creating a plume of microscopic particles. The resulting aerosols are distinct from larger droplets, which quickly fall out of the air due to gravity. Aerosols, or droplet nuclei, are small enough to bypass the filtration capabilities of standard surgical masks and penetrate deep into the lungs of an exposed person. This physical mechanism is what differentiates AGPs as high-risk activities requiring special precautions.
Common medical procedures that often fall into the AGP category include tracheal intubation and extubation, open suctioning of the airways, and bronchoscopy. Other procedures like induced sputum collection, cardiopulmonary resuscitation (CPR), and the use of high-flow nasal oxygen or non-invasive ventilation are also frequently listed as aerosol-generating. The common thread is the significant mechanical manipulation of the respiratory tract that leads to aerosolization.
Airborne Pathogens and Diseases Prevented
Controlling AGPs prevents the transmission of various highly contagious pathogens that spread through the airborne route. The primary concern is for diseases where a small dose of the infectious agent is sufficient to cause illness in a susceptible host. Examples include bacterial infections like Tuberculosis (TB) and viral infections such as Measles.
The recent focus on AGP prevention has been heavily influenced by highly virulent respiratory viruses, including the coronaviruses responsible for Severe Acute Respiratory Syndrome (SARS) and COVID-19, as well as certain strains of Influenza. Performing an AGP on a patient infected with one of these agents significantly increases the concentration of infectious aerosols in the surrounding environment. Strict AGP protocols dramatically lower the risk of infection for healthcare workers who must work in close proximity to the patient during these procedures.
Facility-Level Environmental Control Measures
The first line of defense against aerosol transmission is engineering controls built into the healthcare facility’s infrastructure. The most specialized of these are Airborne Infection Isolation Rooms (AIIRs), also known as negative pressure rooms. These rooms are designed to maintain a lower air pressure than the surrounding corridor, ensuring that air flows only into the room when the door is opened. The negative pressure effectively contains any airborne contaminants within the isolation room.
Air within these specialized rooms is continuously exchanged and exhausted directly outside or passed through High-Efficiency Particulate Air (HEPA) filters before being recirculated. HEPA filters are capable of removing at least 99.97% of airborne particles that are 0.3 micrometers in diameter, capturing the vast majority of infectious aerosols. Standard guidelines recommend that AIIRs achieve a minimum of 12 air changes per hour (ACH) to quickly dilute and remove the infectious particles. After a discrete AGP is completed, the room is often left vacant for a designated period to allow for the removal of airborne contaminants before another patient enters.
Personal Protective Equipment Protocols
Individual protection for personnel performing or assisting with AGPs is achieved through the rigorous use of Personal Protective Equipment (PPE). The most important component is respiratory protection. Healthcare workers are required to wear a fit-tested N95 filtering facepiece respirator or a Powered Air-Purifying Respirator (PAPR). These respirators form a tight seal to the face, ensuring that inhaled air is filtered to capture the minute aerosol particles.
The requirement for fit testing confirms that the specific N95 model achieves a proper seal on the individual’s face, preventing air and aerosols from leaking around the edges. In addition to respiratory protection, the full AGP protocol includes a fluid-resistant gown, gloves, and eye protection, such as a face shield or goggles. This combination of barriers protects the worker’s skin and mucous membranes.