Airborne Precautions

Airborne precautions are intended to prevent the transmission of pathogenic organisms spread by droplet nuclei, i.e., to prevent the transmission of infectious agents that remain suspended in air for long periods and travel long distances from the source such as the rubeola virus, the varicella virus, and Mycobacterium tuberculosis.1 Airborne precautions consist of a three-level hierarchy of (1) administrative controls, (2) environmental controls, and (3) respiratory-protection controls.1,5,6

Primary objectives of administrative controls are to identify and isolate; and ultimately, to either refer the patient with a suspected or confirmed airborne infectious disease to a facility with an airborne infection isolation room (AIIR); or to return the patient home, as deemed medically/dentally appropriate.5,6 A high index of suspicion and rapid implementation of administrative controls are essential to prevent or interrupt the transmission of airborne pathogens.

When reviewing medical histories (initial and/or periodic updates), including a review of organ systems; all patients should be routinely asked about (1) their history of exposure to infectious pathogens, (2) any medical conditions that may increase their susceptibility to infectious diseases, and (3) any signs and symptoms of infectious disease.5 Ideally, the medical history should be elicited from patients in their primary language.

Provisional diagnosis of an airborne infectious disease should be considered for any patient with signs and symptoms of respiratory tract infection. Patients with suspected or documented airborne infectious disease should be isolated from other patients in a private room with the door closed and instructed to observe strict respiratory hygiene/cough etiquette. HCP should wear at least a surgical mask, but preferably an N95 disposable respirator (see respiratory-protection controls below).5

Patients with suspected or confirmed airborne infectious disease requiring urgent dental care must be promptly referred to an oral healthcare facility with an AIIR (see environmental controls below); and while performing procedures on such patients, HCP must use at least an N95 disposable respirator (see respiratory-protection controls below). Routine dental care should be postponed until a physician either rules out infection or confirms that the patient is no longer infectious.5

The second level of hierarchy in airborne precautions is the use of environmental controls. Environmental controls are physical or mechanical measures (as opposed to administrative measures) intended to prevent the spread and reduce the concentration of infectious droplet nuclei less than 5 μm in diameter in ambient air. As noted above, patients with a suspected or confirmed airborne infectious disease requiring dental care must be treated in an AIIR.1,5,6

AIIRs minimize the transmission of infectious agents by droplet nuclei. AIIRs are engineered to (1) provide negative pressure in the room so that air flows under the door gap into the room; (2) have an 6-12 air change rate per hour (ACH), i.e., the volume of the air in the room is changed 6-12 times per hour; and (3) direct exhaust of air from the room to the outside of the building or recirculate air in the room through a high efficiency particulate air (HEPA) filter.1,6,7

Administrative and environmental controls reduce the number of areas in which exposure to airborne pathogens might occur, thus, minimizing the number of persons exposed. However, administrative and environmental control measures do not eliminate the risk of exposure in limited areas. The third level of the hierarchy in Transmission-based Precautions is respiratory-protection controls, i.e., the use of respiratory equipment in situations that pose a high risk for exposure to droplet nuclei.1,5

Oral HCP providing dental care to a patient with suspected or confirmed airborne infectious disease must use a respirator with N95 or higher filtration capacity to prevent inhalation of infectious particles that are less than 5 μm in diameter.1,5 N95 disposable respirators are non-powered, air-purifying, particulate-filter respirators. The N-series respirators are available with filtration efficiencies of 95% (N95), 99% (N99), and 99.7% (N100).7