When are additional (transmission-based) infection control measures necessary? Standard precautions are designed to protect patients and healthcare workers from not only bloodborne pathogens, but those spread by: (1) blood or all body fluids, (2) excretions or secretions (except sweat) regardless of whether they contain blood, (3) nonintact skin, and (4) mucous membranes.1
Under ordinary circumstances, standard precautions have been shown to keep patients and workers safe.2 At times, however, these precautions do not provide sufficient protection against infection, and other steps must be taken in addition to standard precautions based on disease transmission and degree of infection. Such steps are called “transmission-based precautions” and include contact precautions, droplet precautions, and airborne precautions. Some illnesses require more than one type of precaution.
When patients are acutely ill with infectious diseases, they are unlikely to seek dental treatment. It is critical to understand when to use additional precautions if infective patients must be seen, for example in a hospital setting, if an ill patient seeks urgent treatment, or if a healthcare worker becomes infected.
Transmission-Based Precautions
In addition to standard precautions, contact precautions reduce the risk of transmission of epidemiologically important microorganisms by direct or indirect contact.3 Direct contact involves skin-to-skin contact and physical transfer of microorganisms to a susceptible host from an infected or colonized person. Indirect-contact transmission involves contact of a susceptible host with a contaminated object (See chart for contact precautions). Contact precautions apply to patients known or suspected to be infected or colonized with a serious pathogen that might be transmitted by direct or indirect contact. Examples of these illnesses are: gastrointestinal, respiratory, skin or wound infections, or colonization with multi-drug-resistant bacteria judged to be clinically and epidemiologically important.
Examples of infectious conditions requiring contact precautions:
- Clostridium difficile enteric infections
- Ecoli 0157:H7
- Shigella
- Hepatitis A
- Rotavirus
- Respiratory syncytial virus
- Parainfluenza virus
- Enteroviral infections in infants and children
- Highly contagious skin infections (including on dry skin):
- Diphtheria (cutaneous)
- Herpes simplex virus (neonatal or mucocutaneous)
- Impetigo
- Major abscesses, cellulites, or decubiti
- Pediculosis (lice)
- Scabies
- Staphlococcal furunculosis in infants and children
- Zoster (disseminated or in immunocompromised)
- Viral hemorrhagic infections
(Continued from page 1 )
Droplet Precautions
Droplet precautions are taken in addition to standard precautions to reduce the risk of droplet transmission of infectious agents contained in large droplets (>5 µm in size) generated from an infected person.4 This type of transmission involves contact of the conjunctivae or mucous membranes of the nose or mouth of a susceptible person. Droplets are generated during coughing, sneezing, or talking, as well as during dental procedures. Droplet transmission requires close contact as the droplets do not usually travel more than 3 feet. Since droplets do not remain suspended in the air, special air handling systems are not required (See chart for droplet precautions). These precautions apply to patients known or suspected to be infected with epidemiologically important pathogens that can be transmitted by infectious droplets. Examples of droplet-transmitted illnesses are:
- Invasive Haemophilus influenzae type b disease, including meningitis, pneumonia, epiglottitis, sepsis
- Invasive Naisseria meningitides disease, including meningitis, pneumonia, sepsis
- Diphtheria (pharyngeal)
- Mycoplasma pneumonia
- Pertussis
- Pneumonic plague
- Strept. (gp.A) pharyngitis, pneumonia, or scarlet fever in infants and children
- Adenovirus
- Influenza
- Mumps
- Parvovirus B19
- Rubella
Respiratory hygiene/cough etiquette is recommended for dental professionals and patients to control transmission of droplet infections.5 The following precautions are recommended for all individuals with signs and symptoms of respiratory infection to contain respiratory secretions.
- Cover the nose/mouth when coughing or sneezing;
- Use tissues to contain respiratory secretions and dispose of them in the nearest waste receptacle after use; and
- Perform hand hygiene after having contact with respiratory secretions and contaminated objects/materials; and wash hands with nonantimicrobial or antiseptic soap and water or use waterless alcohol-based hand rub.
Healthcare facilities should ensure the availability of materials for adhering to respiratory hygiene/cough etiquette in reception areas.
- Provide tissues and to-touch receptacles for used tissue disposal;
- Provide alcohol-based hand rubs in common areas and reception rooms; and
- Ensure that supplies for handwashing (ie, soap, disposable towels) are consistently available at sinks.
Airborne Precautions
In addition to standard precautions, airborne precautions prevent transmission of serious illnesses that are disseminated and transmitted by either airborne droplet nuclei (small-particle residue of evaporated droplets, 5 microns or less in size, that remain suspended in air for long periods of time) or dust particles containing infectious agent(s).6 Airborne microorganisms carried by small droplet nuclei or dust particles can travel long distances on air currents from the source person. Special air handling and ventilation systems are required to prevent airborne transmission and fit-tested N-95 respirators are required for susceptible workers to treat infected patients. Airborne precautions apply to patients known or suspected to be infected with pathogens that are transmitted by the airborne route. Healthcare workers with airborne diseases should be restricted from work. Examples of airborne illnesses include:
- Measles
- Varicella (including disseminated zoster)
- Tuberculosis
Conclusion
Every day, for every patient, consistent and effective standard precautions will prevent most infections related to patient care. Hand hygiene remains the single most important infection control precaution for preventing disease transmission and will prevent countless infections. Transmission-based precautions are necessary when patients have serious infectious diseases, transmitted by contact, droplets, or small airborne particles.
*OSAP member and consultant on infection control.
References:
- Guidelines for Infection Control in Dental Health Care Settings---2003, Centers for Disease Control MMWR Dec. 19, 2003 / 52(RR17);1-61.
- Standard Precautions, Guideline for Isolation Precautions in Hospitals, Department of Health and Human Services, Centers for Disease Control and Prevention, http://www.cdc.gov/ncidod/dhqp/gl_isolation_Standard.html
- Contact Precautions, Guideline for Isolation Precautions in Hospitals, Department of Health and Human Services, Centers for Disease Control and Prevention, http://www.cdc.gov/ncidod/dhqp/gl_isolation_contact.html
- Droplet Precautions, Guideline for Isolation Precautions in Hospitals, Department of Health and Human Services, Centers for Disease Control and Prevention, http://www.cdc.gov/ncidod/dhqp/gl_isolation_droplet.html
- Respiratory Hygiene/Cough Etiquette (www.cdc.gov/flu/professionals/infectioncontrol/resphygiene.html)
- Airborne Precautions, Guideline for Isolation Precautions in Hospitals, Department of Health and Human Services, Centers for Disease Control and Prevention, http://www.cdc.gov/ncidod/dhqp/gl_isolation_airborne.html
- Guidelines for Isolation Precautions in Hospitals, Department of Health and Human Services, Centers for Disease Control and Prevention, http://www.cdc.gov/ncidod/dhqp/gl_isolation_table.htm.
Tables
Table 1: Comparison of Standard, Contact, Droplet, and Airborne Precautions:
| Standard Precautions | Contact Precautions | Droplet Precautions | Airborne Precautions |
General Instructions | Follow OSHA and CDC Infection Control Guidelines for all procedures. | Follow Standard Precautions and additional steps (below). Additional precautions are necessary to prevent spread of Vancomycin resistance. | Follow Standard Precautions and additional steps (below). Post and practice Hygiene/Cough Etiquette. | Follow Standard Precautions and additional steps (below). |
Applies to: | All patients, including those needing extra precautions. | Patients known or suspected to be infected or colonized with a serious pathogen that might be transmitted by direct or indirect contact. | Patients known or suspected to be infected with a serious pathogen that can be transmitted by large particle droplets. | Patients known or suspected to be infected with a serious pathogen that can be transmitted by small droplet nuclei or dust particles. |
Perform Hand Hygiene | Immediately after touching blood, body fluids, contaminated items even if gloves are worn. Routine: plain soap and water. Specific circumstances: waterless hand rubs / antimicrobial soaps. | Wash hands immediately after removing gloves with antimicrobial agent or use alcohol hand rub. | Perform hand hygiene immediately after contact with contaminated respiratory secretions or contaminated items. | Follow Standard Precautions. |
Gloves | Clean, nonsterile to touch contaminated materials / items. Don just prior to touching mucous membrane or nonintact skin. Change between patients or tasks (same patient). If gloves might transmit pathogens from contaminated to clean area, promptly remove gloves after use and perform hand hygiene. Avoid re-contamination of hands. | Don gloves to enter room. During procedure, change gloves after contact with infective material. Remove gloves before leaving room. Perform hand hygiene immediately. | Follow Standard Precautions. | Follow Standard Precautions. |
Mask, Eye, Face Protection | Wear mask and eye protection / face shield to protect mucous membranes of eyes, nose, mouth from blood, body fluids, secretions, and excretions during splash or spray procedures. | Follow Standard Precautions. | Wear procedure or surgical mask when working within 3 ft. of infected person. | Wear N-95 respirators when entering room of person known or suspected to have airborne respiratory illness. Persons immune to measles (rubeola) or varicella need not to wear N-95 respirator. |
Gown | Wear clean, nonsterile gown during splash or spray or contact procedures to protect skin and clothes to protect from blood, body fluids, secretions, and excretions. Select gown for appropriate fluid resistance. Remove soiled gown as promptly as possible and perform hand hygiene. | Don gown to enter room. Remove gown before leaving room. Isolate used gown and dispose of or route to laundry aseptically. | Follow Standard Precautions. | Follow Standard Precautions. |
Patient Care Equipment | Handle patient care items aseptically; avoid personal contact, injury, and cross-contamination to other patients or environment. Clean and reprocess reusable appropriately. Discard single-use items properly. | If possible, use single-use disposable noncritical patient care equipment. If not possible, clean and disinfect or sterilize items before next use. | Follow Standard Precautions. | Follow Standard Precautions. |
Environ- mental Control | Have supplies and procedures for routine care, cleaning, disinfection of surfaces and equipment. Consistently perform procedures. | Follow Standard Precautions. | Follow Standard Precautions. | Follow Standard Precautions. Consider a wide area (whole room) around the patient contaminated. |
Linen | Handle, transport, and launder linens soiled with blood, body fluids, secretions, and excretions so as to prevent skin and mucous membrane exposure, contamination of clothing, and cross-contamination of surfaces, items, or other patients. | Follow Standard Precautions. | Follow Standard Precautions. | Follow Standard Precautions. |
Bloodborne Pathogen Protections | Prevent injuries during procedures, cleanup, and disposal of sharps. Use barrier resuscitation equipment instead of mouth-to-mouth methods. | Follow Standard Precautions. | Follow Standard Precautions. | Follow Standard Precautions. |
Patient Placement | Place patients who will contaminate the environment or who cannot assist in maintaining asepsis control in a private room. | Place patient in private room. | Place patient in private room. Door may remain open. Maintain spatial separation of at least 3 ft. between infected person and others. | Place patient in private room. Keep door closed. Special facilities with negative pressure treatment rooms and air handling systems are required: 6 – 12 air exchanges / hour, safe discharge of air to outside and high-efficiency filtration of air going to indoor spaces. |
Patient Transport | Provide a safe passageway for patients in public areas. Guide patients in clinical areas to prevent injury and cross- contamination, and preserve clinical asepsis. | Follow Standard Precautions. | Move / transport patient out of private room only if essential. If transport is necessary, minimize dispersal of droplets by masking patient, if possible. | Move / transport patient out of private room only if essential. If transport is necessary, minimize dispersal of droplets by masking patient, if possible. |