Isolation of Patients With Communicable Diseases
Jason Bowling
Jan Patterson
Despite advances in the control of infectious diseases in the last century, there is more interest than ever in the use of isolation precautions to control known and emerging diseases such as colonization with multidrug-resistant bacteria (eg, carbapenem-resistant Enterobacteriaceae), tuberculosis (MDR-TB, XDR-TB), and fungal disease (eg, Candida auris); pandemic or novel influenza; and Clostridioides difficile infection. These precautions are particularly important in the institutional setting due to the proximity and potential common exposures of patients who have communicable diseases with other patients as well as to protect healthcare personnel (HCP). The terminology for isolation precautions has changed and developed over the years.1,2,3 The universal implementation of Standard Precautions has simplified institutional isolation policies, but some of the diseases outlined above may call for additional measures that are not included within “Universal Precautions,” as originally defined. The revision of the guidelines for isolation published in 1996 by the U.S. Centers for Disease Control and Prevention (CDC) approached isolation precautions as transmission-based and clarified some confusing issues.3 Based on the positive results, this approach was reaffirmed in the most recent revision of the guidelines in 2007.4 Still, the healthcare epidemiologist or infection preventionist (IP) is frequently called regarding the appropriate use of isolation precautions.
HISTORICAL PERSPECTIVE
The concept of isolating persons with communicable diseases was in practice even in ancient times according to biblical accounts of leper colonies, although the “leprosy” of biblical times likely included other skin diseases.5 In modern times, hospital construction before 1850 featured crowded open wards.6 As a consequence, cross-infection was common, and mortality rates were high in urban hospitals.7 Florence Nightingale’s observations from the Crimean War8 led her to advocate small pavilion-type wards joined by open-air corridors. Nightingale emphasized the importance of asepsis and a clean environment. Her teachings were called “fever nursing” and varied from popular concepts of disease at the time, because fever nursing implicated transmission by contact with body substances rather than the environment.9
The germ theory of infection was accepted in the U.S. hospitals in the late 1800s, after the influence of Lister and Pasteur, and conditions began to improve as overcrowding decreased and antisepsis increased.7 Communicable disease hospitals were using individual and group isolation as early as 1889.10 By the turn of the century, general hospitals began to isolate patients with communicable diseases in an individual room with the use of separate utensils and disinfectants.9,11 Grancher in Paris promoted the theory of communicability by contact rather than airborne spread for most diseases and allowed patients with communicable diseases to be housed in general wards but with separation by wire screens.9 These screens separated the patient from other patients and served as a reminder for HCP to gown and wash their hands. Thus, the trend began in the United States from the isolation hospital to the care of communicable diseases in a general hospital setting.
In the early 20th century, Charles V. Chapin of Providence City Hospital used individual isolation cubicles for patients with communicable diseases and documented that fumigation had no effect on secondary cases.12 His work was very important in emphasizing the roles of persons rather than things as spreaders of disease and helped to end the miasmatic theory of transmission.13 Richardson, the physician superintendent of Providence City Hospital, used the barrier method and the cubicle method for isolation of patients, allowing some patients with communicable diseases to be housed in the same room as other patients.9 A card outlining the barrier technique needed was placed on the patient’s bed.
The emergence of Staphylococcus aureus as a hospital pathogen in the 1950s and 1960s prompted the development of infection control programs in U.S. hospitals. In 1968, the first edition of the American Hospital Association’s manual13 presented a simple barrier precaution scheme for patients with communicable diseases, listing the need for gloves, gowns, masks, and visitor screening.
EARLY RECOMMENDATIONS FROM THE U.S. CENTERS FOR DISEASE CONTROL AND PREVENTION
While conducting healthcare-associated outbreak investigations in the 1960s, the CDC recognized that standardized policies for isolating hospitalized patients with
communicable diseases were lacking.14 A group of experts convened in 1967 to develop the first CDC isolation recommendations and first published five categories of isolation in 1970.15 Even in this initial manual, the philosophy behind the more recently developed Universal Precautions was expressed. By 1976, a survey showed that 93% of hospitals in the United States were using the category-specific approach to isolation.16
communicable diseases were lacking.14 A group of experts convened in 1967 to develop the first CDC isolation recommendations and first published five categories of isolation in 1970.15 Even in this initial manual, the philosophy behind the more recently developed Universal Precautions was expressed. By 1976, a survey showed that 93% of hospitals in the United States were using the category-specific approach to isolation.16
Substantial changes were made in the 1983 CDC recommendations.1 The updated category-specific guidelines for isolation published in 19831 included seven categories of isolation: strict isolation, respiratory isolation, enteric precautions, contact isolation, tuberculosis (acid-fast bacillus [AFB]) isolation, drainage/secretion precautions, and blood and body fluid precautions. These isolation categories grouped diseases that require the same isolation precautions. After the more recent transmission-based guidelines from the CDC, these categories are now of historical interest, but the terms are still commonly used and confused by some HCP. IPs may be called on to clarify and compare these previous categories with the newer guidelines.
In addition, this 1983 guideline introduced disease-specific isolation as an alternative to category-specific isolation. Disease-specific isolation was offered as an alternative for hospitals wanting a more economic system that directed precautions at preventing transmission of a specific disease while avoiding unnecessary isolation precautions for some diseases. The guidelines stated that hospitals could choose the category-specific or the disease-specific system or design their own systems.
CATEGORY-SPECIFIC ISOLATION
Strict Isolation
Strict isolation was used to prevent transmission of diseases spread by both air and contact. Specifications for strict isolation include a private room with the door closed; masks, gowns, and gloves were indicated for all persons entering the room. This category has now been replaced with the use of Standard Precautions (for all patients) or Contact Precautions combined with Airborne Precautions in the new guidelines.
Contact Isolation
Contact isolation was a category designed to prevent the transmission of epidemiologically important microorganisms causing infection or colonization or highly transmissible microorganisms that do not warrant strict isolation. Conditions in this category are spread by direct (ie, contact directly with patient) or indirect (ie, contact with contaminated room surfaces or equipment) contact. This category has been replaced by Contact Precautions in the new transmission-based guidelines.
Respiratory Isolation
Respiratory isolation was used to prevent droplet nuclei transmission, that is, transmission of diseases over long distances through the air. In the newer guidelines, this category has been replaced by Droplet (ie, transmission via air within close proximity of the patient) or Airborne Precautions (eg, transmission over long distances).
Tuberculosis Isolation (Acid-Fast Bacillus Isolation)
Tuberculosis isolation was referred to as AFB isolation on the standard instruction card to protect patient confidentiality.17 Airborne Precautions have replaced this category in the new guideline. However, there are still many issues pertinent to tuberculosis that warrant special consideration regarding isolation, and these are discussed below (see Duration of Isolation in “Tuberculosis Precautions: Special Considerations” section).
Enteric Precautions
Enteric precautions were used to prevent infections transmitted by feces. Examples would be hepatitis A or bacterial diarrhea. Enteric precautions are now included in Standard Precautions or, in some cases of diapered or incontinent patients, Contact Precautions.
Drainage/Secretion Precautions
Drainage/secretion precautions were used to prevent the transmission of infection by direct or indirect contact with drainage from an infected body site or from purulent material. This isolation category was newly created for the 1983 guidelines and used for many infections isolated under wound and skin precautions or discharge and secretion precautions in the previous guideline. Minor skin, wound, or burn infections that can be adequately covered by a dressing previously included in this category are now covered by Standard Precautions. Major infections not covered or not adequately covered by a dressing are now covered under Standard Precautions or Contact Precautions, depending on the clinical setting.
Blood and Body Fluid Precautions
Blood and body fluid precautions were designed to prevent the transmission of bloodborne pathogens. This category is now only for historical reference because Universal Precautions supersede it. Precautions used for blood and body fluids are now recommended in Standard Precautions, which should be used for the care of all patients.
Comment
The disadvantage of the category-specific isolation was that it was diagnosis- or disease recognition-driven and depended on the caregiver to identify the presence or suspected presence of a disease. After the HIV epidemic, this was no longer acceptable.
DISEASE-SPECIFIC ISOLATION
Disease-specific isolation was one of the two isolation systems recommended by the CDC in 1983.1 In this system, communicable diseases were considered individually with regard to the mode of transmission and infective material, and accordingly, precautions are specified for each disease. The purported advantage of this system is that because precautions are specific for each disease, there are no unnecessary barriers used, and this lowers the cost of isolation. It may also enhance compliance by physicians, who more readily understand the need for specific precautions for each disease. The disadvantage of this system is that because diseases are not grouped by category, it
may be more difficult to train HCPs who are not familiar with specific diseases. Another disadvantage is that, like category-specific isolation, this system is diagnosis-driven, and isolation precautions are often important early in the patient’s hospital stay, before a diagnosis is made or even suspected.
may be more difficult to train HCPs who are not familiar with specific diseases. Another disadvantage is that, like category-specific isolation, this system is diagnosis-driven, and isolation precautions are often important early in the patient’s hospital stay, before a diagnosis is made or even suspected.
IMPACT OF THE HUMAN IMMUNODEFICIENCY VIRUS EPIDEMIC
The recognition of the human immunodeficiency virus (HIV) epidemic in the mid-1980s affected isolation policies in healthcare institutions unlike any other event in modern medicine. Before 1987, most hospitals placed patients in isolation, based on diagnosis or suspected diagnosis, according to the category-specific or disease-specific precautions as outlined by the aforementioned CDC guideline.1 As it became apparent that transmission of HIV could occur from patient-to-HCP, new guidelines were established to minimize exposure to bloodborne pathogens from all patients, not just patients with a diagnosis or suspected diagnosis of HIV infection.2 In contrast to the 1983 CDC guideline, the 1987 CDC document2 recommended blood and body fluid precautions for all patients, regardless of known HIV status. The belief that such precautions were unnecessary in patients not known to have bloodborne pathogens was gone. Specifically, barrier precautions were recommended to prevent contact with blood, certain body fluids, and body fluids containing visible blood. The application of blood and body fluid precautions to all patients was referred to as “universal blood and body fluid precautions” or “Universal Precautions.” In 1988, the CDC published an updated Universal Precautions for the prevention of transmission of HIV, hepatitis B virus (HBV), and other bloodborne pathogens to supplement the 1987 publication.18 This document made it clear that transmission of other bloodborne pathogens, such as HBV, should be prevented as well as that of HIV. In a new precedent for the healthcare industry, the U.S. Occupational Safety and Health Administration (OSHA) became involved in regulating and enforcing these guidelines.19 Now, healthcare institutions were mandated to apply and enforce what was, in effect, blood and body fluid precautions as a minimum standard for protection of the HCP.
Infection control programs recognized the potential benefit of this universal concept as a means of preventing cross-transmitted pathogens (bloodborne and non-bloodborne) among patients and HCPs. It became clear very quickly that an additional isolation system was needed to reduce the risk of transmitting non-bloodborne pathogens, because the CDC-defined Universal Precautions were primarily for preventing transmission of bloodborne pathogens. In the CDC 1988 update,18 category-specific or disease-specific isolation precautions are recommended to fill this need, as described in the 1983 CDC guidelines. IPs at Harborview Medical Center in Seattle, Washington, recognized the problem early. They implemented a Body Substance Isolation system at Harborview in 1984 to control cross-transmission of non-bloodborne pathogens.20 This system designated all body fluids and tissues as potentially infectious. Lynch et al.21,22 described their system and its advantages in preventing the transmission of both bloodborne and non-bloodborne pathogens. The subsequent 1996 CDC guideline for isolation precautions in hospitals includes concepts of both Universal Precautions and Body Substance Isolation. Because of its impact on subsequent guidelines, the concepts of Universal Precautions will be outlined.
UNIVERSAL PRECAUTIONS
The 1987 CDC guidelines recommended the application of blood and body fluid precautions to all patients and designated this policy “Universal Precautions” or “universal blood and body fluid precautions.”17 These guidelines included the following concepts:
HCP should use appropriate barrier precautions to avoid skin and mucous membrane exposure when contact with blood or body fluids from any patient is anticipated. Gloves are to be worn for contact with blood and body fluids, mucous membranes, or nonintact skin; when handling surfaces or items soiled with blood or body fluids; or for venipuncture or other procedures involving vascular access. Gloves should be changed after each patient contact. Masks and protective eyewear or face shields should be worn when procedures are likely to generate aerosols or droplets of blood or other body fluids. Gowns should be worn for procedures that are likely to soil clothing.
Hands or skin contaminated with blood or body fluids should be washed immediately. Hand hygiene should be performed after removing gloves. If nonintact skin or mucous membranes have contact with blood or potentially contaminated body fluids, the healthcare provider should be evaluated for the need for postexposure prophylaxis (HIV, HBV) or follow-up (HCV).
Precautions should be taken to prevent sharps or needlestick injuries. Needles should not be recapped, removed from disposable syringes, or manipulated by hand. After use, needles, disposable syringes, scalpels, and other disposable sharp instruments should immediately be placed in a designated puncture-resistant container.
Mouthpieces and resuscitation devices should be readily available for use in areas where resuscitation procedures may be anticipated.
HCP with exudative skin lesions or nonintact skin on hands or wrists, face, or neck should not be involved in direct patient care or handle patient care equipment until the condition has resolved.
Precautions for Invasive Procedures
These were also outlined in the 1987 document and included routine surgical and obstetric procedures and outpatient physician and dentist office procedures. An invasive procedure was defined as surgical entry into tissues, cavities, or organs or repair of major traumatic injuries in an operating or delivery room, emergency department, or outpatient setting, including both physician and dentist offices; cardiac catheterization and angiographic procedures; vaginal or cesarean delivery or other invasive obstetric procedure during which bleeding may occur; or the manipulation,
cutting, or removal of any oral or perioral tissues, including tooth structure, during which bleeding occurs or the potential for bleeding exists. HCP participating in such procedures should routinely use barrier precautions as needed to prevent skin and mucous membrane exposure to blood and body fluids from all patients. This includes not only gloves and surgical masks for invasive procedures but also protective eyewear or face shields for procedures that are anticipated to generate droplets or splashing of blood or body fluids. Effective barrier gowns should be worn when splashing is anticipated. HCP in obstetrics should use appropriate barrier precautions during deliveries. If a glove is torn or a sharps injury occurs, the glove should be replaced with a new glove. The needle or sharp instrument involved should also be removed from the sterile field.
cutting, or removal of any oral or perioral tissues, including tooth structure, during which bleeding occurs or the potential for bleeding exists. HCP participating in such procedures should routinely use barrier precautions as needed to prevent skin and mucous membrane exposure to blood and body fluids from all patients. This includes not only gloves and surgical masks for invasive procedures but also protective eyewear or face shields for procedures that are anticipated to generate droplets or splashing of blood or body fluids. Effective barrier gowns should be worn when splashing is anticipated. HCP in obstetrics should use appropriate barrier precautions during deliveries. If a glove is torn or a sharps injury occurs, the glove should be replaced with a new glove. The needle or sharp instrument involved should also be removed from the sterile field.
Precautions for Dentistry
Blood, saliva, and gingival fluid from all dental patients should be considered potentially infective in both institutional and noninstitutional settings. Dental HCP should wear gloves for contact with oral mucous membranes and, in addition, surgical masks and protective eyewear or face shields for procedures in which splashing of blood or body fluids is likely. Guidelines for disinfection or sterilization of dental equipment should be followed. Infection control precautions for dentistry are more specifically outlined and updated in later recommendations.23
Precautions for Autopsies or Mortician Services
Persons participating in postmortem procedures should wear appropriate barrier protective equipment including respiratory protection. Equipment and surfaces contaminated during such procedures should be cleaned with an appropriate chemical germicide.
Precautions for Dialysis
Blood and body fluid precautions are to be used when dialyzing all hemodialysis patients, not just those identified as hepatitis B surface antigen positive or HIV positive. HIV-infected patients do not need to be isolated from other patients during hemodialysis. The dialyzer may be discarded after use. Institutions that reuse dialyzers may designate a specific single-use dialyzer to a specific patient for reuse after appropriate cleaning and disinfection on the same patient only. HIV-infected patients may be included in the reuse programs; individual dialyzers must never be used on more than one patient.
Precautions for Laboratories
Blood and other body fluid specimens from all patients are considered infective. Specimens should be placed in a wellconstructed container with a secure lid to avoid leakage. Contamination of the outside of the container or the laboratory form should be avoided. Personnel who process specimens should wear gloves. Other barrier protection should be used as needed if splashing or aerosolization is anticipated. Biologic safety cabinets should be used for procedures that are likely to generate droplets or aerosols. After specimen processing, gloves should be changed and hands washed. Mechanical devices should be used for pipetting; mouth pipetting should never be done. Laboratory work surfaces and laboratory equipment should be decontaminated with an appropriate chemical germicide after blood or body fluid spills and when work is completed. Before leaving the laboratory, personnel should remove protective clothing and wash their hands.
UPDATE: UNIVERSAL PRECAUTIONS, 1988
After the recommendations for Universal Precautions were published in 1987, hospitals scurried to write their own institutional policies and implement training for their personnel in the prevention of bloodborne diseases in the workplace. In 1988, the CDC published an update to Universal Precautions that indicated these precautions were also for the prevention of other bloodborne pathogens such as HBV and specified that only specific body fluids implicated in the transmission of bloodborne pathogens needed to be included under Universal Precautions.18 Many hospitals already had policies in place and employees trained by this time, which contributed to confusion in the use of the term Universal Precautions. The 1988 update also included further clarification on the use of protective barriers, the use of gloves for phlebotomy, the selection of gloves, and waste management.
Body Fluids to Which Universal Precautions Apply
In terms of occupational exposures, blood is the most important source of HBV, HIV, and other bloodborne pathogens. Infection prevention efforts aimed at preventing occupationally acquired bloodborne infections must emphasize prevention of exposures to blood and promotion of HBV immunization. Universal Precautions apply to semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, amniotic fluid, and any body fluid containing visible blood.
Body Fluids to Which Universal Precautions Do Not Apply
According to the 1988 update, Universal Precautions do not apply to feces, nasal secretions, sputum, sweat, tears, urine, and vomitus unless they contain visible blood. The risk of bloodborne pathogen transmission from these fluids is very low or nonexistent. The 1983 CDC guidelines (category-specific or disease-specific isolation) are cited for the prevention of non-bloodborne pathogen transmission. Tears, saliva, sweat, urine, feces, and respiratory secretions are not considered other potentially infectious fluids capable of transmitting bloodborne pathogens. However, under the current Standard Precautions, appropriate personal protective equipment (PPE) (eg, gloves, gowns, eye protection, etc.) should be used to prevent contact with all body fluids except sweat. While Standard Precautions do not routinely apply to saliva, special precautions are reiterated for dentistry because contamination of saliva with blood is predictable with dental procedures.
Use of Protective Barriers
The types of barriers needed for different procedures and clinical situations vary, so the HCP must use appropriate judgment. Barrier precautions do not prevent sharps injuries; thus, caution in handling needles and sharps
instruments, as previously outlined, is also necessary. Protective barriers should be used when exposure to blood or the above-named body fluids is anticipated. Hands or other surfaces contaminated with blood or the specified body fluids should be washed immediately with an antiseptic.
instruments, as previously outlined, is also necessary. Protective barriers should be used when exposure to blood or the above-named body fluids is anticipated. Hands or other surfaces contaminated with blood or the specified body fluids should be washed immediately with an antiseptic.
Glove Use for Phlebotomy
Although gloves may reduce the amount of blood contaminating hands during venipuncture, they do not prevent needlestick injuries. The likelihood of exposure during phlebotomy depends on the skill of the personnel, the cumulative risk of the HCP, whether the procedure is in a routine or emergency setting, and the prevalence of bloodborne pathogens in the patient population. Even though blood from all patients is considered infectious, the prevalence of HIV or HBV in volunteer blood donor centers is known to be low. Some centers, therefore, have not routinely recommended gloves for phlebotomy in these settings. However, the OSHA bloodborne standard requires that gloves be worn “when it can be reasonably anticipated that the employee may have hand contact with blood, other potentially infectious materials.”
Glove Selection
The U.S. Center for Devices and Radiological Health, a branch of the Food and Drug Administration (FDA), is responsible for the regulation of the medical glove industry. Medical gloves include sterile surgical/procedural or nonsterile examination gloves made of vinyl, nitrile, or latex. Due to the high frequency of latex allergies in HCP in the past, more healthcare facilities no longer use latex gloves. The gloves selected should be task appropriate, and the following are general guidelines. Sterile gloves should be used for contact with sterile body areas or invasive procedures/surgeries. Nonsterile examination gloves may be used for contact with nonsterile body areas or other procedures that do not require aseptic technique. Gloves must be changed between patient contacts. Gloves should not be washed or disinfected between patients. Exposing the gloves to surfactants used for washing may cause increased penetration of liquids through unseen holes in the glove (wicking). Disinfectants may damage the gloves. Generalpurpose utility gloves (rubber household gloves) should be used for housekeeping activities and instrument cleaning in which contact with blood or specified body fluids is anticipated. These gloves can be reused after decontamination but should be discarded if torn or visibly damaged. Since the publication of this 1988 update, there have been many studies published evaluating glove integrity (see below, “Are Gloves an Effective Barrier?”).
Waste Management
Guidelines on waste management remain unchanged from the 1987 recommendations, but local, state, and federal regulations in many areas now supersede these recommendations, and this has been acknowledged.
Comment
Universal Precautions have the advantage of protecting the HCP against unidentified bloodborne pathogen risks. Also, this system is simpler than traditional systems, because the blood and body fluid isolation category applies to all patients. However, the 1988 update, which was intended to clarify which body fluids are infectious, only served to confuse the issue because it is often difficult at the bedside to discern whether a body fluid contains blood. Furthermore, it is sometimes difficult to know the origin of a body fluid at the bedside and even more so when the specimen is removed from the bedside.
ARE GLOVES AN EFFECTIVE BARRIER?
At the time of the publication of the 1988 CDC update, there were no published data on the preference of latex vs vinyl gloves. Since that time, there have been numerous studies addressing the integrity of gloves in general and latex vs vinyl gloves in particular. The standards for testing the integrity of latex gloves were established by the American Society for Testing and Materials (ASTM) of the FDA, and compliance with them is voluntary. In 1977, the standard allowed no more than 15 defects per 1000 (1.5%) sterile unused latex surgical gloves, as determined by the watertight method of testing, and 25 defects per 1000 (2.5%) latex examination gloves.24 In 1989, the FDA method for testing gloves improved, and the standards changed to an allowable defect rate of 2.5% for surgeon’s gloves and 4.0% for examination gloves.25 Due to the continued concern of potential transmission of bloodborne pathogens HIV, HBV, and hepatitis C virus (HCV), the FDA issued a final rule effective December 19, 2008, which further reduced the allowable defect rate for examination gloves to 2.5%. The FDA, using calculated projections based on available CDC data on HIV, HBV, and HCV infections, estimated that this modification in acceptable quality levels could potentially avoid seven cases of HIV infection and seven cases of chronic HBV infection transmitted to healthcare workers over a 10-year period.26
There are no standards for vinyl gloves. Concern regarding occupational exposure to HIV raised the issue of glove integrity in the clinical setting. In addition, some cases of herpetic whitlow in intensive care unit (ICU) nurses who used gloves focused more attention on this issue.27 Scanning of gloves by electron microscopy has documented inapparent pits from 30 to 50 µm in size, suggesting the possibility that viruses could penetrate this barrier.28
In addition, several studies have documented leakage rates higher than the ASTM standard of 1.5%-2.5%. Although several brands of sterile latex surgical gloves were impermeable to water and blood, some brands showed leakage rates of up to 8%.29 Nonsterile latex and vinyl gloves showed leakage rates of 0%-52%. Nonsterile packaging or packaging in suction kits increased leakage rates. When gloves were stressed by conditions mimicking those encountered in patient care, 63% of vinyl gloves leaked a stock solution of bacteriophage compared with 7% of latex gloves.30 Penetration of 20% of latex gloves and 34% of vinyl gloves by S marcescens has also been documented.31 These studies indicate that gloves reduce the risk of gross soilage from blood or body fluids but that they are not 100% effective.
Latex hypersensitivity due to repeated exposure and sensitization of the healthcare worker to latex antigens has led to the adoption of nonlatex gloves made out of various synthetic materials such as neoprene, polyurethane, and nitrile. Latex and nonlatex surgical gloves were examined
for defects after use by surgeons during surgical procedures, and overall glove defect rates were 5.6% and 7.5% for latex and nonlatex surgical gloves, respectively.32 Based on the data obtained during this review of surgical gloves, the authors recommended that surgeons change gloves within 2-3 hours to avoid exceeding defect rates >5%.
for defects after use by surgeons during surgical procedures, and overall glove defect rates were 5.6% and 7.5% for latex and nonlatex surgical gloves, respectively.32 Based on the data obtained during this review of surgical gloves, the authors recommended that surgeons change gloves within 2-3 hours to avoid exceeding defect rates >5%.
Doebbeling et al.33 showed that washing gloved hands was not effective for decontamination, and in fact, 5%-50% of hands were contaminated after gloves were removed. Washing gloves has also been shown to decrease their integrity.34 Thus, gloves should not be washed and reused between patients. These studies affirm that although gloves can be used as a barrier to reduce gross contamination from blood and body fluids, antisepsis after glove removal remains very important because occult breaks in gloves can and do occur.
The surgical literature has long been concerned with perforations in gloves during surgical procedures. In 1899, Bovie35 stated that careful handwashing was needed, because gloves could be punctured accidentally during an operation. More recent studies have quantitated the number and location of inapparent perforations that may occur in gloves during surgical or dental procedures. Albin et al.36 showed a 33% leak rate of latex gloves randomly studied after surgical procedures. These authors also documented a leak rate of up to 5.5% in unused gloves. Gloves studied sequentially showed a leak rate of 58.5% at the end of surgical procedures and 32% at the end of dental procedures. Double gloving decreased the leak rate to 25%. In the sequential surgical study, 52% of the leaks occurred in the first 75 minutes; in the sequential dental study, 75% of the leaks occurred in the first 30 minutes. Gloves used in cardiovascular, orthopedic, abdominal, and oral surgical procedures had leak rates of more than 50%. The frequency of occult glove perforation has been noted to be as high as 10% after interventional radiologic procedures.37 In the Albin et al. study evaluating surgical and dental procedures, leak rates for gloves were evaluated for various members of the surgical team and were found to be highest for the surgeon (52%), followed by the first assistant (29%) and then the scrub nurse (25%).36 Most perforations (60%) occurred in the thumb or index finger of the glove. Other studies have also documented that the largest number of perforations occur in the thumb, index finger, and middle finger.38,39
IMPACT OF UNIVERSAL PRECAUTIONS
Universal Precautions are now a minimum standard in U.S. hospitals as a result of OSHA regulations. To review the advantages of these systems over category-specific or disease-specific isolation, the latter systems may be inconsistently or incorrectly applied, whereas precautions that are used for all patients not only are easier to implement but also protect cross-transmission from patients who may lack signs or symptoms of a disease. Furthermore, there is less psychological trauma for individual patients identified as having a microorganism transmissible by blood or body fluids because all patients are treated in a standard manner. Because of HCP concern about HIV in particular, this system at least theoretically eliminates the need for routine screening of all patients and personnel for HIV at periodic intervals—a process that would prove extremely costly.40
Some disadvantages of the Universal Precautions concept have been proposed. Because gloves were used more extensively for barrier precautions in Universal Precautions, some HCPs have sometimes neglected to change gloves between patients,41,42 and such practices have been associated with cross-transmission of microorganisms.43,44 Education and reinforcement of appropriate use of gloves and changing gloves between patients can be successful in reducing such practices.22,43
The effectiveness of Universal Precautions has been evaluated using the frequency of personnel nonparenteral exposures to blood and body fluids (including sputum, urine, feces) as a monitor. Fahey et al.45 and Wong et al.46 documented a significant decrease in nonparenteral exposures to blood and body substances after the implementation of Universal Precautions. Saghafi et al.47 also documented a reduction in exposure of unprotected skin to blood, but the rate of needlestick exposures remained unchanged. So although Universal Precautions may significantly reduce nonparenteral exposures to blood or body fluids, other measures such as engineering controls are needed to reduce parenteral exposures such as needlesticks.
As Universal Precautions were implemented throughout the country, glove use increased substantially, and cost became a concern. Doebbeling and Wenzel48 evaluated the costs of using Universal Precautions. Universal Precautions increased the total annual costs for isolation materials at a large university teaching hospital by $350 900—an increase, adjusted for inflation, from $13.70 to $22.89 (67%) per admission. These authors estimated that Universal Precautions cost ˜$269 million annually nationwide (using the dollar value from 1989) in hospitals alone and ˜$67 million in the outpatient setting, accounting for $336 million total per year nationwide.
Although these systems are expensive, the alternatives must be considered. The alternative of testing all patients admitted to U.S. hospitals each year is estimated to be $2.6 billion or approximately eight times the cost of Universal Precautions.49 Further, testing is not feasible for all patients for the expanded list of pathogens requiring Contact Precautions such as multidrug-resistant Gram-negative bacilli, enteric pathogens (e.g., C. difficile, norovirus, etc.) and C. auris. Thus, Universal Precautions are less expensive than universal testing. In addition, a decrease in healthcare-associated infection rates has been documented after the implementation of Universal Precautions,48 providing further evidence for the cost-benefit of these systems in the United States.
UPDATED CDC GUIDELINES (1996-2007): UNIVERSAL PRECAUTIONS EVOLVE INTO STANDARD PRECAUTIONS
The CDC’s isolation guidelines were revised again by the CDC’s Healthcare Infection Control Practices Advisory Committee in 1996.3 The guideline contained three important changes from previous recommendations. First, “Standard Precautions” combine the major features of Universal Precautions and Body Substance Isolation.
These precautions apply to all patients regardless of diagnosis or known infection status. This first tier of precautions is used to decrease the risk of transmission from recognized or unrecognized infection. Second, the previous categories of isolation (strict isolation, contact isolation, respiratory isolation, enteric precautions, drainage/secretion precautions) and the previous disease-specific precautions are superseded by the three types of transmission-based precautions. These precautions are based on routes of transmission for patients known or suspected to be infected or colonized with highly transmissible or epidemiologically significant pathogens. Third, the new guideline lists specific syndromes in adult and pediatric patients that are suspicious for infection and indicate which precautions to use on an empiric basis pending diagnosis. As with previous guidelines, the CDC recognized that no guideline adequately addresses each hospital’s needs. Individual hospitals and healthcare systems are encouraged to review the recommendations and modify them according to their own needs and resources.
These precautions apply to all patients regardless of diagnosis or known infection status. This first tier of precautions is used to decrease the risk of transmission from recognized or unrecognized infection. Second, the previous categories of isolation (strict isolation, contact isolation, respiratory isolation, enteric precautions, drainage/secretion precautions) and the previous disease-specific precautions are superseded by the three types of transmission-based precautions. These precautions are based on routes of transmission for patients known or suspected to be infected or colonized with highly transmissible or epidemiologically significant pathogens. Third, the new guideline lists specific syndromes in adult and pediatric patients that are suspicious for infection and indicate which precautions to use on an empiric basis pending diagnosis. As with previous guidelines, the CDC recognized that no guideline adequately addresses each hospital’s needs. Individual hospitals and healthcare systems are encouraged to review the recommendations and modify them according to their own needs and resources.
The 2007 guidelines are the most current guidelines at the time of publication of this text.4 They expanded the guidance from the 1996 guidelines to include settings outside acute care, such as long-term care and home-based care. In addition, the term healthcare-associated infections has taken the place of “nosocomial infections.” After the 2003 severe acute respiratory syndrome (SARS) and concern for pandemic influenza, respiratory hygiene and cough etiquette were added to the guidelines. There is an update on protective precautions for severely immunocompromised patients and additional recommendations regarding the PPE necessary to perform certain procedures and environmental and administrative controls required for a safer healthcare environment. The 2007 guidelines reiterate Standard Precautions and transmission-based precautions as keystones of infection prevention in healthcare settings. Table 3-1 outlines the categorization of diseases by transmission-based precautions in accordance with these guidelines.
Transmission requires a source of infection, a susceptible host, and a mode of transmission. Transmission-based precautions intend to interrupt this cycle by interfering with the mode of transmission. Sources of infection may include patients, HCPs, and visitors, as well as the environment.50,51,52
The risk of acquiring healthcare-associated infections varies based on the setting where the patients are located. It is particularly high in the ICU. In other settings, such as long-term care facilities (LTCFs), patients stay for prolonged periods of time. Patients at LTCFs are encouraged to participate in activities involving other residents, and this may result in increasing the risk of microorganism transmission. The isolation precautions used in acute care may not be practical in an LTCF, and prevention of transmission may be challenging. (See also Chapter 32 “Epidemiology and Prevention of Infections in Post-Acute Care Facilities.”)
Tiers to Prevent Transmission of Infectious Agents
There are two main tiers of the HICPAC/CDC guidelines to prevent transmission of infections in healthcare settings regardless of the presence of an infectious agent. The first tier is the most important strategy to prevent healthcareassociated transmission of infectious agents: Standard Precautions. The second tier is the institution of transmission-based isolation precautions.
Standard Precautions
Standard Precautions combine Universal Precautions and Body Substance Isolation and are based on the premise that “all blood, body fluids, secretions, excretions (except sweat), nonintact skin, and mucous membranes regardless of suspected or confirmed infectious status” may be infectious.4 Standard Precautions involve important interventions including hand hygiene, use of PPE (based on anticipated exposure), and safe injection practices, as well as appropriate management of environment and equipment.
The 2007 guidelines added to previous recommendations the use of respiratory hygiene/cough etiquette, safe injection guidelines, and use of a mask during certain procedures such as injection of material into spinal or epidural spaces or insertion of catheters into the epidural space.4
Hand hygiene should be performed with soap or an antiseptic (eg, chlorhexidine) and water if hands are visibly soiled. Alcohol-based hand sanitizers should be used after visible soil is removed with soap and water or if hands are not visibly soiled. Hand hygiene should be performed before direct contact with patients; after contact with blood, body fluids, excretions or mucous membranes, nonintact skin, or wound dressings; after contact with intact skin if hands move from a contaminated to a noncontaminated body site; or after contact with objects close to the patient or after removing gloves.53
For Standard Precautions, mask and eye protection or a face shield should be used to protect the eyes, nose, and mouth during activities that may generate splashing of blood or body fluids. A gown should be worn to protect the skin and prevent soiling of clothing during such activities as well. Reusable equipment should be cleaned and disinfected before being used on another patient. Ensure adequate disinfection of environmental surfaces. Handle soiled equipment and laundry in a manner that avoids exposures and transfer of microorganisms to other patients and the environment.
Care should be taken to avoid sharps injuries. Never recap used needles or use a technique that involves directing the point of the needle toward any part of the body. Place used sharps in a puncture-resistant container. Use mouthpieces or resuscitation bags instead of mouth-tomouth resuscitation in areas where the need for cardiopulmonary resuscitation is predictable.
A patient who contaminates the environment or who cannot assist in using appropriate hygiene should be placed in a private room. If a private room is not available, seek consultation from an IP regarding placement.
Transmission-Based Precautions
The second tier of precautions is for patients with documented or suspected transmissible or epidemiologically significant pathogens that require more than Standard Precautions to prevent cross-transmission. Healthcare-associated pathogens may be transmitted by five major routes: contact, droplet, airborne, vector-borne, and
common vehicle. The isolation guidelines are not generally relevant to vector-borne and common vehicle routes. Transmission-based precautions are of three types: Airborne Precautions, Droplet Precautions, and Contact Precautions. Types may be combined for diseases with multiple routes of transmission, and each type is used in addition to Standard Precautions. Another feature of the current guidelines is a list of specific syndromes in adult and pediatric patients that should be considered possibly infectious along with a listing of the type of transmissionbased precautions that should be used empirically pending diagnosis.
common vehicle. The isolation guidelines are not generally relevant to vector-borne and common vehicle routes. Transmission-based precautions are of three types: Airborne Precautions, Droplet Precautions, and Contact Precautions. Types may be combined for diseases with multiple routes of transmission, and each type is used in addition to Standard Precautions. Another feature of the current guidelines is a list of specific syndromes in adult and pediatric patients that should be considered possibly infectious along with a listing of the type of transmissionbased precautions that should be used empirically pending diagnosis.
TABLE 3-1 Types of Isolation Precautions | ||
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It is generally recommended that isolation precautions be implemented empirically as soon as a potential transmissible infection is suspected to reduce the risk of secondary transmission, recognizing that precautions can be modified once a diagnosis is confirmed. Specific examples of this practice would be empiric contact isolation precautions for a patient on multiple antibiotics who develops diarrhea when C difficile infection is suspected or empiric droplet precautions for a patient with potential influenza infection.
Airborne Precautions
Airborne transmission usually occurs when a susceptible host inhales airborne droplet nuclei or small particles from an infection source containing microorganisms (ie, tuberculosis) that may be dispersed over long distances. In addition to respiratory protection with an N95 mask or powered air-purifying respirator (PAPR), prevention of airborne transmission requires use of special ventilation systems.
Airborne Precautions are used to prevent transmission of microorganisms that persist suspended in the air for long distances (eg, Mycobacterium tuberculosis). These patients should be placed in airborne infection isolation rooms. These rooms are negative pressure rooms with >12 air exchanges per hour in new construction and >6 exchanges per hour on existing buildings, with air exhausted directly to the exterior or recirculating through high-efficiency particulate air (HEPA) filters.
HCP should wear an N95 mask or PAPR when entering the room. The mask should be fit-tested yearly in all HCPs or when the providers’ facial features are altered.
When airborne isolation rooms are not available, the patient should be placed in a private room with the door closed, and HCP should wear N95 respirators/PAPR. Patients should remain in their room as much as possible, and they should wear a surgical mask if they need to be transported to essential procedures. Ideally, a portable HEPA machine should be placed in the room until transport to an airborne isolation room occurs.
Droplet Precautions
Droplet transmission occurs when an infectious agent is transmitted (usually) from the respiratory tract of a patient to the mucous membranes of another susceptible patient by respiratory droplets that travel short distances through the air. The distance is usually 3 ft, but there are cases where it may travel up to 6-10 ft, especially in the setting of severe infections of SARS.54 Some of these cases were due to lack of appropriate use of PPE.54
Droplets may be generated in the course of talking, coughing, or sneezing and during procedures involving the airway, such as intubation or bronchoscopy. Transmission via large droplets differs from airborne transmission in that the former requires close proximity between the source and the recipient person and because large droplets do not remain suspended in the air and usually travel only short distances. Examples of diseases for which Droplet Precautions are recommended are meningococcal meningitis, multidrug-resistant pneumococcal meningitis or pneumonia, pertussis, streptococcal pharyngitis or pneumonia, seasonal influenza, and parvovirus B19 (for patients with aplastic crisis or chronic infection). Occasionally, pathogens not usually transmitted by way of droplets can be transmitted through this route, such as S aureus in the setting of pneumonia. The patient should be placed in a private room. If a private room is not available, patients with infection due to the same microorganism may be cared for in the same room (cohorted). If both private rooms and cohorting are unavailable, an IP should be consulted. There should be spatial separation of at least 3 ft between the infected patient and other patients and visitors. A mask should be worn when one is within close proximity of the patient. It is most practical to wear a mask upon entering the room. The patient should leave the room only when necessary and should wear a surgical mask when doing so.
There are pathogens that are usually transmitted through droplets or contact but under special circumstances have been suspected to be transmitted through the airborne route such as SARS-associated coronavirus,
influenza, and norovirus.55,56,57 Droplet Precautions with a surgical mask are recommended for routine care of influenza patients. For procedures that will cause aerosolization of respiratory droplets, an N95 respirator or PAPR should be used.
influenza, and norovirus.55,56,57 Droplet Precautions with a surgical mask are recommended for routine care of influenza patients. For procedures that will cause aerosolization of respiratory droplets, an N95 respirator or PAPR should be used.
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