The healthcare environment uses a structured system of safety measures, known as transmission precautions, to prevent the spread of infectious agents. These protocols protect patients, healthcare personnel, and visitors from exposure to pathogens. By establishing clear rules for handling potentially infectious situations, healthcare facilities create layers of defense against disease transmission.
Understanding Standard and Transmission Based Precautions
Infection control in healthcare follows a two-tiered system, beginning with a universal set of practices called Standard Precautions. These are the minimum infection prevention practices used for all patient care, regardless of a patient’s suspected or confirmed infection status. They include routine hand hygiene, safe injection practices, and the use of personal protective equipment (PPE) like gloves when contact with body fluids is anticipated.
Transmission-Based Precautions represent the second tier, layered on top of Standard Precautions when a patient is known or suspected to be infected with a pathogen that spreads via specific routes. The three categories—Airborne, Droplet, and Contact—are tailored to interrupt the unique way an infectious agent travels. These targeted measures are necessary because Standard Precautions alone are often insufficient to halt the spread of highly transmissible diseases.
Preventing Disease Spread Through Air
Airborne Precautions are reserved for diseases spread by very small particles, known as aerosols, that can remain suspended in the air and travel over long distances. Examples of infections requiring this level of precaution include tuberculosis, measles, and varicella (chickenpox). These minute infectious particles can be inhaled by anyone in the shared airspace, necessitating specialized environmental controls.
The primary requirement is placing the patient in an Airborne Infection Isolation Room (AIIR), also called a negative pressure room. The negative pressure ventilation system maintains a lower air pressure inside the room than in the hallway outside. This pressure difference ensures air flows into the room, preventing contaminated air from escaping into other areas of the facility.
The air from an AIIR is typically exhausted directly to the outside or passed through a High-Efficiency Particulate Air (HEPA) filter before being recirculated. Healthcare personnel entering the room must wear a specialized respirator, such as an N95 mask or a Powered Air-Purifying Respirator (PAPR). The N95 respirator must be individually fit-tested to the wearer to ensure a tight seal and is capable of filtering out at least 95% of airborne particles.
Precautions for Droplet Transmission
Droplet Precautions target pathogens spread by larger respiratory droplets expelled when an infected person coughs, sneezes, or talks. Unlike aerosols, these droplets are relatively heavy, traveling only a short distance—generally three to six feet—before gravity causes them to fall onto surfaces. Common infections requiring these precautions include seasonal influenza and pertussis.
The main intervention in Droplet Precautions is source control and masking for close contact. Healthcare personnel must wear a simple surgical mask upon entering the patient’s room or when working within the three-to-six-foot range of the patient. The patient should also be placed in a private room, if possible, to limit the spread.
Specialized air handling or ventilation systems, like the negative pressure rooms used for airborne pathogens, are not necessary for droplet transmission. If the patient must leave the room for a procedure, they should be instructed to wear a surgical mask to contain the droplets at the source. This focus on masking and distance is effective because the pathogen does not remain suspended in the air for extended periods.
Controlling Spread Via Direct Contact
Contact Precautions are the most common type and are implemented for infections spread through direct touch with the patient or indirect touch with contaminated objects or surfaces in the patient’s environment. Pathogens like Methicillin-resistant Staphylococcus aureus (MRSA), Vancomycin-resistant Enterococcus (VRE), and Clostridioides difficile (C. difficile) are managed with these protocols. The use of disposable personal protective equipment is central to preventing this form of transmission.
Healthcare providers must don a clean gown and gloves before entering the patient’s room. This equipment serves as a barrier, preventing the transfer of the infectious agent to the provider’s skin or clothing. Both the gown and gloves must be carefully removed and discarded inside the room before the provider exits to prevent environmental contamination.
Patient-care equipment, such as stethoscopes and blood pressure cuffs, should be dedicated to that single patient and remain in the room. For infections like C. difficile, which produces resilient spores, hand hygiene requires washing hands with soap and water. Alcohol-based hand sanitizers are less effective at physically removing these spores compared to the mechanical action of washing.