October 10, 2013 — This article discusses the two primary types of Isolation Precautions: (i) Standard Precautions and (ii) Transmission-based Precautions (which include Contact Precautions, Droplet Precautions and Airborne Precautions).
1. Standard Precautions
The Centers for Disease Control and Prevention’s (CDC) recommends a two-tiered approach to the prevention of disease transmission.(1,2)
Standard Precautions are the first-tier of Isolation Precautions and are intended as the primary strategy to prevent the transmission of infectious agents through exposure in the healthcare setting to:
- all body fluids,
- secretions and excretions (except sweat);
- non-intact skin; and
- mucous membranes.
Standard Precautions are sufficient to interrupt the spread of most infectious agents. — Lawrence F Muscarella PhD
Standard Precautions — a key component of which is the use of physical barriers to prevent disease transmission — apply to all patients, regardless of their diagnosis or presumed infection status, and include such practices as:
- hand hygiene;
- the use of gloves, masks, and gowns;
- respiratory hygiene/cough etiquette; and
- safe injection practice; and reprocessing reusable instruments and equipment.(1,2)
Quality and Safety Services and Case Reviews for Hospitals, Manufacturers, Patients: Click here to read about Dr. Muscarella’s quality and safety services committed to reducing the risk of healthcare-associated infections, including CRE outbreaks linked to contaminated endoscopes and other reusable medical equipment.
2. Transmission-based Precautions
Transmission-Based Precautions — the second-tier of Isolation Precautions — are performed when Standard Precautions alone are insufficient to prevent disease transmission.(1,2)
Attention, Ebola: In addition to Standard Precautions, implementation of both Contact Precautions and Droplet Precautions are recommended for patients known to have, or suspected of being infected with, Ebola Virus Disease (or, EVD) in U.S. hospitals. Airborne Precautions may too, under certain circumstances, be recommended. — Lawrence F Muscarella PhD (click here for more details).
These additional control measures are intended only for the care of patients known or suspected to be infected or colonized with epidemiologically important infectious agents transmitted by one or more of the following routes:
- direct or indirect contact;
- large-particle droplets; or
- airborne droplet nuclei.
Such infectious agents include Ebola and Enterovirus D68.
The three types of Transmission-Based Precautions that correspond, respectively, to each of these three routes, or modes of transmission, are:
- Contact Precaution;
- Droplet Precautions; and
- Airborne Infection Isolation Precautions (previously known as Airborne Precautions).(1,2)
The infectious agent’s mode(s) of transmission, along with empirical data including the patient’s symptoms, determine which one (or more) of these three types of precautions is used to interrupt disease transmission.
Whereas one infectious agent, such as “MRSA,” may require Contact Precautions (in addition to Standard Precautions) to prevent additional infections, another infectious agent, such as Mycobacterium tuberculosis, may instead require Airborne Infection Isolation Precautions.(1,2)
Click here to read the CDC’s “2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Setting.”
2A. Contact Precautions
Contact Precautions are intended to prevent infections of “epidemiologically important” infectious agents, such as Ebola and Enterovirus D68, transmitted by direct or indirect contact with an infected or colonized patient or the patient’s potentially contaminated surrounding environment.
Skin-to-skin contact is an example of direct contact, and contact with items in the environment is an example of indirect contact.
The spread of “nightmare bacteria” known as carbapenem-resistant Enterobacteriaceae, or CRE, “can be controlled with proper precautions and better practices. Standard infection control precautions include washing hands and dedicating staff, rooms and equipment to the care of patients with CRE. Prescribing antibiotics wisely can significantly reduce the problem.” — The Washington Post.
Contact Precautions (which are practiced in addition to Standard Precautions) include (but are not limited to) practitioners:
- cohorting colonized or infected patients together (if single-patient private rooms are unavailable);
- wearing gloves and a gown when entering the room or area of a patient on these precautions;
- performing hand hygiene after removing these gloves and gown;
- using disposable, single-use (or patient-dedicated) non-critical medical equipment (such as blood pressure cuffs and stethoscopes); and
- the cleaning and disinfection of any potentially contaminated environmental surfaces.(1,2)
Carbapenem-resistant Klebsiella pneumoniae, like MRSA (methicillin-resistant Staphylococcus aureus), is an example of an epidemiologically important infectious agent for which Contact Precautions is often indicated to interrupt its transmission and prevent additional infections.
2B. Droplet Precautions
Droplet Precautions are intended to prevent infections transmitted by large-particle droplets (i.e., > 5 µm in size).
Infected patients may produce large-particle droplets during coughing, sneezing, talking, or during, among other types of procedures, endotracheal intubation and bronchoscopy.
Large-particle droplets do not remain infectious over long distances and, therefore, generally require close contact (i.e., < 3 feet) for transmission.
Droplet Precautions include (but are not limited to) practitioners:
- cohorting patients separated by at least 3 feet if single-patient private rooms are unavailable;(1,2)
- wearing a facemask (e.g., a surgical mask) upon entering the exam room;
- wearing gloves, a gown, and eye protection (e.g., goggles or a face shield) if substantial spraying of respiratory fluids is anticipated;
- performing hand hygiene before and after touching the patient and after contact with respiratory secretions and any potentially contaminated objects/surfaces; and
- the cleaning and disinfection of any potentially contaminated environmental surfaces.(1,2)
Haemophilus influenzae is an example of an infectious agent spread by large-particle droplets. So, too, can both the Ebola virus and Enterovirus D68 be transmitted from patient-to-patient via such droplets..
Attention, Enterovirus D68: Interestingly, the precautions employed in U.S. hospitals to prevent transmission of the Enterovirus D68 (EV-D68) are essentially the same as those used for Ebola. In addition to Standard Precautions, implementation of both Contact Precautions and Droplet Precautions are recommended for patients infected with the EV-D68 (click here for more information). Measures to prevent EV-D68 transmission in the community setting include hand washing and avoiding close contact with sick, infected people (click here for more information). — Lawrence F Muscarella, PhD
2C. Airborne Infection Isolation Precautions
Airborne Infection Isolation Precautions are intended to prevent infections transmitted by airborne droplet nuclei or small particles 5 µm or smaller in size.
Infected patients may produce these airborne particles during coughing, sneezing, talking, or during, among other procedures, endotracheal intubation and bronchoscopy. These airborne particles can remain infectious in the air for several hours and can travel over long distances.(1,2)
Mycobacterium tuberculosis, measles, and chickenpox are examples of infectious agents spread by airborne droplet nuclei, thereby warranting the implementation of Airborne Infection Isolation Precautions to prevent their spread. (The Enterovirus D68 does not require employment of these airborne precautions in the healthcare setting to prevent its transmission. See “Attention,” below, for the Ebola virus.)
Airborne Infection Isolation Precautions include immediately placing patients in private rooms with negative air pressure (whenever possible) — once known as negative pressure isolation rooms, these are now called airborne infection isolation rooms (“AIIRs”), which are single-occupancy patient-care rooms used to isolate persons with a suspected or confirmed airborne infectious disease.(1,2)
Other precautions include (but are not limited to) practitioners:
- wearing a fit-tested respiratory protection (e.g., N95 or higher level respirators, or masks if respirators are unavailable) prior to entering to entering the exam room;
- wearing gloves, a gown, and eye protection (e.g., goggles or a face shield) if substantial spraying of respiratory fluids is anticipated; and
- performing hand hygiene before and after touching the patient and after contact with respiratory secretions and any potentially contaminated objects/surfaces.(1,2)
The CDC recommends that healthcare facilities employ Standard, Contact and Droplet Precautions for the management of patients infected (or suspected of being infected) with the Ebola virus (click here).
However, when performing an aerosol generating procedure on an Ebola-infected (or -suspected) patient, employing certain Airborne Infection Isolation Precautions, such as performing the procedure in a private room (ideally, in an AIIR, when feasible), and staff practitioners wearing respiratory protection (e.g., a fit-tested N95 filtering face-piece respirator) is recommended.
Update (10-15-14): Based on the possibility that the Ebola virus, possibly, could be transmitted through airborne particles (which reportedly has not occurred previously in Ebola’s history), New Jersey’s nursing association is recommending (click here) that the state’s 80,000 healthcare professionals use a respirator when treating patients suspected of having Ebola — a step beyond the current CDC guideline to use a facemask.
According to this nursing association’s executive director: “It’s conjecture, but it’s better safe than sorry when you’re really dealing with these things”
That said, the data confirming that Ebola can be spread from person-to-person via the airborne route is lacking. Therefore, the importance of Airborne Infection Isolation Precautions becoming standard protocol for preventing Ebola’s spread in healthcare settings is unclear.
- Hospital Infection Control Practices Advisory Committee. CDC Guideline for Isolation Precautions in Hospitals. Infect Control Hosp Epidemiol 1996; 17:53-80. http://wonder.cdc.gov/wonder/PrevGuid/p0000419/p0000419.asp
- Centers for Disease Control and Prevention. Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings 2007. June, 2007. http://www.cdc.gov/ncidod/dhqp/pdf/guidelines/Isolation2007.pdf
Article by: Lawrence F Muscarella PhD, president of the healthcare quality company LFM Healthcare Solutions, LLC (click here); posted 1/16/2013; updated 10-1-2015, Rev A.
Email: Larry@LFM-HCS.com; Twitter: @MuskiePhD