Understanding Transmission-Based Precautions
The foundation of infection control in any healthcare setting begins with
standard precautions, which are applied to the care of all patients regardless of their diagnosis. However, when a patient is known or suspected to be infected with certain pathogens, additional measures called
transmission-based precautions are required to interrupt the specific route of transmission. According to the AORN guideline, these precautions are categorized into contact, droplet, and airborne, and they are always used in addition to standard precautions
[1].
The key to selecting the correct precaution type lies in understanding the physical properties of the infectious particle, specifically its size and behavior in the air. This determines how far it can travel and how long it can remain suspended, which directly informs the necessary personal protective equipment (PPE) and patient placement.
Analysis of Each Option
1. A patient with methicillin-resistant Staphylococcus aureus (MRSA) wound infection
MRSA is primarily transmitted via direct or indirect contact with the infected wound or contaminated items. The infectious particles are large droplets or reside on skin and surfaces, not traveling long distances through the air. Therefore, this patient requires
contact precautions in addition to standard precautions. This involves wearing a gown and gloves for any interaction that may involve contact with the patient or their environment
[1].
2. A patient with Clostridium difficile-associated diarrhea
Clostridium difficile is a spore-forming bacterium transmitted via the fecal-oral route through contact with contaminated surfaces. The spores are hardy and not suspended in the air for extended periods. This patient requires
contact precautions, with a critical emphasis on hand hygiene with soap and water, as alcohol-based hand rubs are not effective against C. difficile spores
[1].
3. A patient with influenza A
Influenza viruses are transmitted through large respiratory droplets that are generated when an infected person coughs, sneezes, or talks. These droplets are relatively heavy and typically travel only a short distance (about 3 to 6 feet) before falling to the ground. They do not remain suspended in the air for long periods. Consequently, a patient with influenza A requires
droplet precautions. A surgical mask is the appropriate respiratory protection for the nurse
[1].
4. A patient with pulmonary tuberculosis (Correct Answer)
Mycobacterium tuberculosis is carried in tiny airborne particles called droplet nuclei, which are less than
5 microns in size. These are generated during coughing, sneezing, or certain aerosol-generating procedures. Unlike large droplets, droplet nuclei can remain suspended in the air for hours and can travel through ventilation systems over long distances. Because of this ability to be widely dispersed via air currents, a patient with suspected or confirmed pulmonary tuberculosis requires
airborne precautions in addition to standard precautions. The guideline specifies that this includes placing the patient in a negative-pressure airborne infection isolation room (AIIR) and the use of a fit-tested N95 respirator or higher-level respirator by all healthcare personnel entering the room
[1]. The risk assessment for infective airborne particles is a critical component of the updated perioperative guidelines, highlighting the need to identify procedures that may generate such particles and to implement appropriate controls
[1].
References (research sources)