Isolation Precautions

In the late 1980s, the CDC prepared a series of guidelines for health care workers who have contact with patients or body fluids.^{[51] [94]} They were subsequently incorporated into the OSHA standard on occupational exposure to blood-borne pathogens.^[31] The recommendations can

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In 1996, the CDC published an all-encompassing guideline on nosocomial transmission of diseases. The new guideline, called isolation precautions, addresses the potential that contact with any bodily emission may be hazardous to health care workers. In addition to direct contact, the hazards include all body fluids, secretions, and excretions and airborne droplets. The guideline includes methods of hand washing and gloving, patient placement, transport of infected patients, design and use of protective gear for medical personnel, equipment used in patient care, linen, laundry, and cleaning of spaces inhabited by infected patients. ^[95]

The guideline is composed of two tiers, standard precautions and transmission-based precautions. Standard precautions merge the principles of universal precautions and body substance isolation, which was proposed in 1987 to reduce the risk of transmission of pathogens from moist body substances through the use of gloves. Standard precautions should be used during all encounters with patients. Transmission-based precautions are necessary in the management of patients known to be or suspected of being infected or colonized with epidemiologically important pathogens. The isolation methods used depend on the pathogen involved.^[95]

Despite the adoption of standard precautions, contaminated needlestick injuries in health care workers persisted at an unacceptable rate. In 2000, the CDC estimated that more than 380,000 contaminated percutaneous injuries occur in hospital workers in the United States on an annual basis.^[96] As a result, Congress revised the blood-borne pathogen standard to include the "Needlestick Safety and Prevention Act" (H.R. S178).^{[97] [98]} The act emphasizes the use of safety devices and needle-less systems, in addition to requiring employers to establish an exposure control plan with records documenting each incident. Since the act was signed into law in November 2000, as part of a comprehensive program to prevent the transmission of blood-borne pathogens in health care workers, the National Institute for Occupational Safety and Health has called for the elimination of needle devices when "safe and effective alternatives are available." This recommendation was based on accumulating evidence in the 1990s showing that devices with safety features could reduce needlestick injuries.^[99]

Standard Precautions

Standard precautions should be practiced at all times. The following are taken almost verbatim from CDC publications.^{[31] [94] [95]} Barrier precautions appropriate for the procedure being performed, including gloves, gowns, masks, and eye shields, should be worn when the potential for contact with blood or body fluids is present. Precautions apply to blood, all body fluids, secretions, and excretions except sweat, regardless of whether they contain visible blood; nonintact skin; and mucous membranes. Strict attention should be given to hand washing after gloves are removed, even if there has been no direct contact with blood or fluid. Needles should not be recapped, bent, or broken by hand but instead should be discarded in a puncture-resistant container. Resuscitation equipment that prevents the need for mouth-to-mouth contact should be available. All specimens sent to laboratories should be handled as though they are infected.

Transmission-Based Precautions

Transmission-based precautions should be followed when patients are known to be or are suspected of being infected with highly transmissible or epidemiologically important pathogens. These precautions are based on the properties of specific pathogens and are to be used in addition to standard precautions.

1. Airborne precautions are to be used when transmission of small particles or droplets (<5 µm) is likely. Because these particles can be carried for long distances, special filtration and air handling are necessary. Diseases in this category include measles, varicella, and tuberculosis.
2. Droplet precautions apply to diseases transmitted by large particles (>5 µm). Because of their size and because the droplets do not remain suspended in air, transmission is limited to short distances; a meter or less is the norm. Examples include invasive Haemophilus influenzae type b (meningitis, epiglottitis), Mycoplasma pneumoniae, streptococcal pharyngitis, and rubella.
3. Contact precautions apply to direct skin-to-skin contact, including hands. Indirect contact may also occur if surfaces in an infected patient's environment are contaminated. Included are colonies of antibiotic-resistant organisms, hepatitis A virus, herpes simplex virus, viral conjunctivitis, and major abscesses.^[95]