Chapter 162: Occupational Exposures, Infection Control, and Standard Precautions

The U.S. Occupational Safety and Health Administration defines occupational exposure as a "reasonably anticipated skin, eye, mucous membrane, or parenteral contact with blood or other potentially infectious materials that may result from the performance of the employee's duties."¹ Blood is defined as "human blood, blood products, or blood components."¹ Other potentially infectious materials are defined as "human body fluids, such as saliva, semen, and vaginal secretions; cerebrospinal, synovial, pleural, pericardial, peritoneal, and amniotic fluids; any body fluids visibly contaminated with blood; unfixed human tissue or organs; HIV [human immunodeficiency virus] or HBV [hepatitis B virus] containing cell or tissue cultures, culture mediums, or other solutions; and all body fluids where it is difficult or impossible to differentiate between body fluids."¹ Healthcare workers should treat all bodily secretions, fluids, and tissues as potentially infectious.

The Hospital Infection Control Practices Advisory Committee of the Centers for Disease Control and Prevention lists select infections and conditions that may be encountered in the ED, along with recommended occupational exposure precautions.^2,3,4 The concept of standard precautions is built on the premise that healthcare workers cannot readily identify patients who are infected or at risk for infection. This is why using infection control practices and personal protective equipment during all patient care activities is key.

U.S. Occupational Safety and Health Administration federal regulations prescribe safeguards to protect workers and reduce risk of exposure to blood and body fluids.⁵ Updated and detailed standards (known as the Bloodborne Pathogens Standard) are in Title 29 of the Code of Federal Regulations and amended by the Needlestick Safety and Prevention Act.^6,7 The standards require healthcare facilities (1) to develop a written exposure control plan, (2) to use engineering controls to reduce risk by removing the hazard or isolating the worker from exposure, (3) to use work practice controls to standardize and maximize the safety with which work tasks are performed, (4) to identify mechanisms for compliance with Title 29 standards, and (5) to communicate workplace hazards to those with potential for bloodborne disease exposures. The Centers for Disease Control and Prevention and U.S. Occupational Safety and Health Administration Web sites provide the most up to date information regarding current regulations and standards.

Portals for infectious disease entry are percutaneous, mucous membrane (oral, ocular, nasal, vaginal, or rectal), respiratory, and dermal. The risk of infection in an exposed healthcare provider depends on (1) the route (portal) of exposure, (2) the concentration (number of organisms) of the pathogen in the infectious material, (3) the infectious characteristics (virility) of the pathogen, (4) the volume (dose) of infectious material, and (5) the immunocompetence (susceptibility) of the exposed individual.

Percutaneous exposures pose the highest risk of transmission for bloodborne disease. Needle sticks and lacerations by sharp objects account for the majority of percutaneous injuries. Phlebotomy, initiation of IV access, manipulation of access devices, suturing, and medication injection all put workers at risk.

Mucous membrane exposures result from splatters, splashes, and sprays of blood and body fluids. Tasks associated with risk of mucous membrane exposure include wound management (hemorrhage control, exploration, irrigation, debridement), airway suctioning, nasogastric or orogastric tube placement, intubation, and specimen handling.

Respiratory exposures occur through inhalation of airborne or droplet particulate materials. Exposure risk grows when an individual is confined with an expectorating, coughing, or sneezing patient for prolonged periods or in a poorly ventilated environment.

Dermal exposure involves skin contact with patients (direct contact) or environmental surfaces or objects contaminated with infectious materials (indirect contact). The risk of infection increases if the contact involves a large surface area or nonintact skin (abraded, chapped, or excoriated). Drug-resistant organisms (e.g., methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci) and parasites of the integument (e.g., scabies, lice) are transmitted by dermal exposure. Workplace activities associated with dermal exposure include patient examination, turning or moving patients, and changing linens or wound dressings. Healthcare workers are also at risk for hypersensitivity reactions to specific inert substances, notably latex, after prolonged or repeated dermal exposure.

Infection control practices seek to prevent transmission of microbial agents and to provide a wide margin of safety for healthcare workers. These practices include hand washing; use of personal protective equipment; cleaning, disinfecting, and sterilizing patient care equipment and environmental surfaces; decontamination and laundering of soiled uniforms, clothing, and patients' linens; disposal of needles, sharps, and infectious waste; and patient location. Infection control measures that are simple, part of the routine work environment, and uniform across all situations have the greatest likelihood of compliance.

A complete infection control program includes administrative controls, equipment engineering, work practice controls, education of the workforce, and medical management.

Administrative controls organize, define, and direct infection control activities. The written infection control (exposure) plan defines all policies, procedures, and activities related to the education, prevention, and management of infectious diseases in the workforce. Initial and recurrent training in infectious disease hazards and risk activities must be provided to all healthcare workers.

Equipment engineering reduces employee exposure by removing hazards or isolating healthcare workers from exposure. Examples include self-sheathing needles, needleless drug administration devices, sharps containers, disposable airway equipment, syringe splash guards, and personal protective equipment. Medical safety devices reduce occupational exposures experienced by healthcare personnel and should be used whenever possible.

Personal protective equipment is "specialized clothing or equipment which does not permit blood or potentially infectious substances to pass through or reach worker clothing, skin, eyes, mouth, or other mucous membranes under normal conditions of use."¹ Personal protective equipment includes examination gloves, facemasks, eye protection, face shields, and impervious gowns, leggings, and shoe covers. Personal protective equipment mitigates occupational exposures experienced by healthcare personnel; it limits but does not eliminate exposure risks. Recommendations for task-specific use of personal protective equipment are provided in Table 162-1.⁸

Work practice controls modify the performance of a task to minimize exposure to blood and blood-containing body fluids and infectious materials. Work practice controls include policies to guide disposal of needles and sharps containers (i.e., avoid shearing, bending, recapping, or breaking); disposal of contaminated linens, clothing, and infectious waste; disinfection of reusable equipment; and restriction of employee activities (eating, drinking, smoking, and application of cosmetics) in work areas where there is a reasonable likelihood of exposure to blood and body fluids.

Workforce education includes information about the agents of infectious disease, epidemiology, disease transmission, signs and symptoms, risky work activities, risk reduction strategies, and postexposure management. Education must occur at the time of initial employment, with recurrent training at specified intervals.

Medical management practices include preexposure preventive vaccinations, postexposure medical evaluation, testing, infectious disease counseling, disease prophylaxis, and referral. The U.S. Occupational Safety and Health Administration mandates preexposure vaccines at initial employee training and within 10 days of employment for all personnel at risk of exposure.¹ The Advisory Committee on Immunization Practices and the Hospital Infection Control Practices Advisory Committee make specific recommendations concerning the use of certain immunizing agents in healthcare personnel.⁹

Once an infectious exposure has occurred, healthcare workers should have access to a plan for postexposure prophylaxis (PEP) medical management 24 hours a day. The plan should include immediate medical assessment, risk analysis, counseling, treatment and prophylaxis, and follow-up appropriate to the type and source of the exposure.^{9,10,11,12,13,14}

An outline for a standardized initial approach is shown in Table 162-2.¹¹

The medical record of care for the exposed patient (the occupational exposure report) should contain specific information relative to the exposure incident. Key elements include the circumstances of exposure, medical history of the source person, and medical history of the exposed person per Centers for Disease Control and Prevention recommendations (Table 162-3).¹⁰

INITIAL TREATMENT AND ASSESSMENT

Thoroughly wash exposed wounds and skin sites with soap and water, and irrigate mucous membranes with water. Do not apply caustics (bleach), antiseptics, or disinfectants directly to the wound.

Evaluate the exposure event for the potential to transmit hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV) based on the type of body substance involved and the route and volume of the exposure (Table 162-4).¹⁰ Blood, fluid containing visible blood, human tissue, or other potentially infectious material (including semen, vaginal secretions, and cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids) may transmit bloodborne viruses. Percutaneous injury or mucous membrane contact with these substances conveys risk for virus transmission. Dermal contact with these substances does not convey risk of virus transmission unless the skin is not intact (abraded, chapped, excoriated, open wound).

TESTING FOR EXPOSURE

Perform diagnostic testing to determine the hepatitis B virus, hepatitis C virus, and HIV infection status of an exposure source as soon as possible and with consent (Table 162-5).¹⁰ If possible, obtain a rapid HIV-antibody on the exposure source; direct viral assays (HIV p24 antigen enzyme immunoassay, HIV RNA, hepatitis C virus RNA) are not recommended. Testing of needles or sharps instruments for contamination is also not recommended. If the exposure source is HIV positive, obtain additional information as available including CD4+ T-cell count, viral load, current and previous antiretroviral therapy, and history of antiretroviral resistance and prognosis to help identify optimal PEP regimen. If this information is not known at the time of exposure, do not delay the initiation of PEP, as changes in the regimen may be made on follow-up within 72 hours after exposure.¹⁰

HEPATITIS B VIRUS EXPOSURE AND PEP

Factors in the management of hepatitis B virus exposure include the hepatitis B surface antigen status of the source and the hepatitis B vaccination and vaccine response status of the exposed person. Following a percutaneous exposure, the estimated risks of hepatitis in unvaccinated healthcare workers are 22% to 31% (source patient positive for hepatitis B surface antigen and hepatitis B e antigen) and 1% to 6% (source patient positive for hepatitis B surface antigen and negative for hepatitis B e antigen). The estimated risk of transmission is lower following mucous membrane exposure, nonintact skin exposure, or an exposure involving nonbloody fluids or tissues.¹⁰ Every unvaccinated healthcare worker exposed to blood or body fluids should receive the hepatitis B vaccine series. For the rest, recommendations for PEP following hepatitis B virus exposure vary according to the hepatitis B surface antigen status of the exposure source and the vaccination/vaccine-response status of the exposed person (Table 162-6).¹⁰ If hepatitis B immunoglobulin is indicated, give it as soon as possible after the exposure (ideally within 24 hours); after 7 days, the effectiveness of hepatitis B immunoglobulin is unknown.

The Hepatitis Hotline provides guidance to clinicians with regard to the acute and chronic management of hepatitis (1-888-443-7232, http://www.cdc.gov/hepatitis).

HEPATITIS C VIRUS EXPOSURE

For occupational hepatitis C virus exposures, the Centers for Disease Control and Prevention recommends anti–hepatitis C virus testing of the source patient. Test the exposed person for anti–hepatitis C virus and alanine aminotransferase at baseline and follow-up (at 4 to 6 months), and testing for hepatitis C virus RNA may be performed at 4 to 6 weeks after exposure if needed to aid early diagnosis of hepatitis C virus. Confirm all positive anti–hepatitis C virus tests by enzyme immunoassay with supplemental testing (i.e., recombinant immunoblot assay). If the source patient is hepatitis C virus infected, the mean estimated risk of transmission is 1.8% after a percutaneous exposure (range 0% to 7%). Estimated risk of transmission is even lower following mucous membrane exposure, nonintact skin exposure, or an exposure involving nonbloody fluids or tissues.¹⁰ Immunoglobulin and antivirals are not recommended for PEP after exposure to hepatitis C virus–positive blood.

Healthcare workers exposed to hepatitis B virus– or hepatitis C virus–infected blood do not need to take any precautions to prevent secondary transmission during the follow-up period; however, they should not donate blood, plasma, organs, tissue, or semen.

HIV EXPOSURE AND PEP

Healthcare workers potentially exposed to HIV should receive expedited evaluation and baseline testing for HIV. Factors in the management of HIV exposure include the type of exposure (percutaneous, mucous membrane, or dermal), the volume of the exposure (small or large), and the HIV status of the source. Risk of HIV transmission following percutaneous exposure increases with exposure to a larger quantity of blood as indicated by (1) a device visibly contaminated with blood, (2) a needle placed in the source patient's artery or vein, (3) a large-bore hollow needle, or (4) a deep injury.¹⁶ If the source patient is HIV infected, the estimated risk of transmission is 0.3% after a percutaneous exposure and 0.09% after a mucous membrane exposure. Estimated risk of transmission following a nonintact skin exposure or an exposure involving nonbloody fluids or tissues is even lower.¹⁴

If the source patient has a negative HIV antibody test, baseline testing and further follow-up of the exposed person are not normally necessary. If the source patient has a positive HIV antibody test, consider the source to be HIV positive regardless of viral load for the purpose of PEP and follow-up testing. Exposure to a source patient with an undetecTable viral load does not eliminate the possibility of HIV transmission. If the source patient is suspected to have acute retroviral syndrome, consider the source to be HIV positive regardless of HIV test result.

PEP should be initiated as soon as possible; if later testing determines the source to be HIV negative, discontinue PEP. PEP is less effective if started more than 24 to 36 hours after exposure. The interval after which no benefit is gained is unknown, so start PEP even when the postexposure interval exceeds 36 hours.

The U.S. Public Health Service provides guidelines for PEP following occupational exposure to HIV.¹⁴ Guidelines now recommend three (or more) tolerable antiretroviral drugs for all occupational exposures to HIV as shown in Tables 162-7 and 162-8. Anticipate side effects and consider preemptive prescribing of ameliorating medications to improve PEP regimen adherence.¹⁴ Also, consult with a local expert or with the National Clinicians' Post-Exposure Prophylaxis Hotline (PEPline at 1-888-448-7737) for the more complex situations listed in Table 162-9. If a delay in obtaining expert input occurs, start postexposure therapy immediately, allowing later discontinuation based on new information or expert consultation. The optimal duration of PEP is unknown, but the Centers for Disease Control and Prevention recommends 4 weeks of treatment.¹⁰

Following an exposure to HIV, advise healthcare workers to be reevaluated within 72 hours to assess information about the source patient. Also, emphasize the importance of adherence to the PEP regimen for the duration of treatment. Similarly, recommend that all exposed healthcare personnel try to prevent secondary transmission, especially during the first 6 to 12 weeks after exposure, by doing the following: use condoms or exercise sexual abstinence; refrain from donating blood, plasma, organs, tissue, or semen; avoid pregnancy; and, if possible, avoid breastfeeding. Advise exposed workers to seek medical evaluation for any acute illness that occurs during the follow-up period, as this may signal the onset of acute retroviral syndrome. Follow-up testing includes HIV testing at baseline and at 6 weeks, 12 weeks, and 6 months after exposure, usually concluded 4 months after the exposure if a newer fourth-generation HIV p24 antigen-HIV antibody test is negative.

Other infectious diseases require special precautions, preventative measures, and postexposure care in order to minimize the risk of occupational exposure. Common sources of other occupational exposures are listed in Table 162-10. Maintain high suspicion for disease in populations at risk, and institute isolation precautions promptly when disease is considered.

The Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee promulgates two tiers of precautions: standard and transmission based. Standard precautions assume a broad approach to healthcare personnel and patient protection by including agents transmitted by routes other than blood. Transmission-based precautions are designed for patients with documented or suspected transmissible pathogens for which additional protection beyond standard precautions is required. Transmission-based precautions are of three types: airborne, droplet, and contact. Transmission-based precautions are to be used in addition to, not in place of, standard precautions.^2,3,4

STANDARD PRECAUTIONS

Standard precautions are exercised when caring for all patients and include hand washing/sanitization, gloves, mask and eye protection or face shield, gowns, handling of patient care equipment and linens, environmental controls, workplace controls, and patient location or placement depending on the indication.

Hand Washing

Hand washing is required after touching blood, body fluids, secretions, excretions, and contaminated items even if gloves are worn. Wash hands immediately after gloves are removed, between patient contacts, and when otherwise indicated to avoid the transfer of organisms to other patients or environments. It may be necessary to wash hands between procedures on the same patient to prevent cross-contamination of different body sites. Plain soap and water are recommended for routine use. Washing with an antimicrobial agent or waterless antiseptic may be done for control of outbreaks or hyperendemic infections, but some pathogens, such as Clostridium difficile,²⁹ are not eradicated by alcohol-based antiseptics.

Gloves

Use clean, nonsterile gloves when touching blood, body fluids, secretions, excretions, and contaminated items. Change gloves between tasks and procedures involving blood or other potentially infectious materials. Remove gloves and wash hands before touching noncontaminated items or environmental surfaces (e.g., phones, light switches, writing implements) or other patients.

Masks and Shields

Facemasks, eye protection, and face shields that are fluid resistant are worn to protect mucous membranes of the eyes, nose, and mouth during patient care activities and procedures likely to generate splashes or sprays of blood, body fluids, secretions, excretions, and infectious materials. Replace masks that are soiled, moistened by the user's exhaled vapor, or contaminated by fluids as soon as possible. Protective function may be lost when the barrier device is completely saturated.

Gowns

Clean, nonsterile gowns that are fluid resistant protect the worker's skin and clothing during patient care activities and procedures likely to generate splashes or sprays of blood, body fluids, secretions, and excretions. Replace soiled gowns as soon as possible because barrier protection is lost if the garment is saturated with contamination. Use sleeve protectors, booties, and leggings if exposure to a large volume of contamination or infectious material is anticipated.

Disposal

Handle patient care equipment and linens soiled with blood, body fluids, secretions, and excretions specifically to avoid skin and mucous membrane exposure, contamination of clothing, and transfer of microorganisms to other patients and environments. Reusable items should be cleaned and reprocessed to eliminate infectivity. Promptly discard single-use items.

ENVIRONMENTAL AND WORK PRACTICE CONTROLS

Environmental controls include hospital procedures for the decontamination of objects in patient care areas. Clean and disinfect environmental surfaces, beds, bed rails, bedside equipment, and frequently touched surfaces between patient uses.

Workplace controls (work practice controls) include proper disposal of needles, scalpels, and other sharp instruments. Avoid recapping, excessive handling, and manipulation of sharp devices. Use self-sheathing devices and puncture-resistant containers, and replace sharps containers before they overflow. Patients who contaminate the environment or those who cannot assist in their own hygiene should be located in a private room if available.

AIRBORNE PRECAUTIONS

In addition to standard precautions, use airborne precautions for patients known or suspected of being infected with microorganisms transmitted by airborne droplet nuclei. Airborne precautions also apply to small-particle (<5 μm) residue of evaporated droplets containing microorganisms that remain suspended in the air and can be widely dispersed by air currents. Examples of infectious agents spread by this method are found in Table 162-11.²

ISOLATION

Isolate ED patients requiring airborne precautions in an airborne infection isolation room with (1) monitored negative air pressure in relation to surrounding areas, (2) 6 to 12 air changes per hour, and (3) discharge of the room air to the outdoors or high-efficiency filtration of the air before it is circulated to other areas in the hospital. The patient must remain in the isolation room with the door closed. Limit the movement in and out of the room and transportation of the patient. When movement is unavoidable, the patient should wear respiratory protection to avoid contamination of other areas within the hospital. Healthcare workers entering the room must wear respiratory protection, such as a personalized, fitted mask with efficient filters (approved particulate respirator).

DROPLET PRECAUTIONS

In addition to standard precautions, use droplet precautions for patients known to have or suspected of having serious illnesses transmitted by large particle droplets (>5 μm). Droplets are generated during talking, sneezing, or coughing and during the performance of procedures. Examples of infectious agents spread by this method are listed in Table 162-12.^2,4

ISOLATION AND FACE MASKS

Place the patient in a private room when possible. Prioritize patients with excessive cough and sputum production to available single-patient rooms. Special air handling and ventilation are not required, and the door may remain open. If a private room is not available, the patient may be placed in a room with other patients who have active infections with the same microorganism (i.e., cohorting). If cohorting is also not possible, place a mask on the patient and maintain a spatial separation of at least 3 ft (1 m) between the infected patient and other patients and visitors. Avoid placing patients with droplet precautions in the same room with patients at increased risk for adverse outcomes from infection. Limit the movement and transportation of patients with droplet precautions. When movement is required, place a face mask on the patient. Healthcare workers should wear face masks when working within 3 ft (1 m) of the patient. Healthcare workers should wear respiratory protection equivalent to a fitted N95 filtering respirator or higher level of protection during aerosol-generating procedures such as suctioning. Change protective attire and perform hand hygiene between contacts with all patients.

CONTACT PRECAUTIONS

In addition to standard precautions, use contact precautions when patients are known to have or suspected of having serious illnesses transmitted by direct patient contact or contact with items in the patient's environment. Examples of such infectious diseases are shown in Table 162-13.^2,4

Change gloves whenever the examination and care of a patient result in contact with infectious materials and a high concentration of microorganisms (wound drainage or fecal material). When expecting contact with infectious materials (incontinence, dressing changes, attention to colostomy), wear a clean, nonsterile gown and gloves. Remove the gown and gloves before leaving the care area. Wash hands with an antimicrobial agent or waterless antiseptic after removal of gloves, and avoid contact with potentially contaminated environmental surfaces or items in the room after hand washing.

Limit transportation and movement of the patient. When movement is required, cover contaminated areas with large, bulky dressings. Bulky, adsorbent, leakproof dressings contain contaminated secretions and limit spread of disease.

Durable, multiuse medical equipment (e.g., blood pressure cuffs, stethoscopes, bedside commodes) should be dedicated to a single patient (or cohort of similarly infected patients). Personnel who use personal medical equipment (e.g., stethoscopes) should thoroughly clean these items between patient contacts to avoid contamination.

Rubber latex is a manufactured polymer that exhibits excellent tensile strength, elasticity, and barrier capacity.³⁰ Rubber latex is in many medical products, including gloves (for surgery, examination, and housekeeping and cleaning), intravascular devices (balloon catheters, IV tubing, and ports), airway devices (nasopharyngeal airways, endotracheal tubes, and oxygen masks), tourniquets, blood pressure cuffs, ECG leads, tape, and dressings.

REACTIONS TO LATEX

Immune reactions to latex products may take three forms: irritant, contact dermatitis (type IV), and immunoglobulin E (type I).

Irritant reactions are nonimmune in nature and result in dry dermal erythema limited to the site of contact.

Contact dermatitis occurs as a result of dermal exposure to chemicals used in the manufacturing of latex products. Thirams and thiazoles are the most common chemicals to induce this type IV response. This reaction, which may extend beyond the site of contact, results in a dry dermal erythema, pruritus, weeping, and vesiculation. Such loss of skin integrity permits the access of latex proteins to the immune system and may result in an immunoglobulin E–mediated response.

An immunoglobulin E (type I) response is an immunologic reaction to protein allergens contained in latex. Clinical manifestations of such reactions include urticaria, asthma, rhinitis, angioedema, laryngeal edema, and anaphylaxis. Immunoglobulin E reactions may occur as a result of mucosal, dermal, contact, or inhalational exposure. Cornstarch powder, which serves as a lubricant to ease the donning of latex gloves, binds and aerosolizes protein allergens, leading to inhalation exposure.

At highest risk of developing immunoglobulin E–mediated latex allergy are those with high exposure to latex and who are atopic. Workers in industries that make rubber products (e.g., tire manufacturers and doll makers) and those who use rubber products (e.g., housekeepers, hairdressers, and healthcare workers) are at high risk of developing this allergy. Although anyone can develop latex allergy, those at higher risk have a history of multiple allergies, asthma, eczema, multiple food allergies, frequent surgical or dental procedures, spina bifida and related conditions of spinal dysraphism, urogenital anomalies, or sensitivity to ethylene oxide (a sterilizing agent).

LATEX-FREE PRODUCTS AND MINIMIZING LATEX ALLERGY

Many latex-free medical products exist on the market and may be substituted for currently used products. Prevention of disease in healthcare workers is critical and requires the use of synthetic or low-allergen powder-free gloves.^30,31 To protect themselves from latex exposure and allergy in the workplace, healthcare personnel may also use nonlatex gloves for workplace activities that do not involve contact with infectious materials, use synthetic or low-allergen powder-free gloves when handling infectious materials, avoid oil-based hand lotions or creams when wearing latex gloves (to prevent glove deterioration), wash hands with mild soap and dry thoroughly upon removal of latex gloves, frequently clean work areas and equipment contaminated with latex-containing dust, obtain education and training regarding latex allergy, and recognize the symptoms of latex allergy. Hypoallergenic latex gloves do not reduce the risk of latex allergy but do reduce reactions to chemical additives in latex.

The National Clinicians' Post-Exposure Prophylaxis Hotline offers 24-hour telephone consultation for physicians managing occupational exposures to bloodborne pathogens (888-448-7737, http://www.nccc.ucsf.edu). The Hepatitis Hotline provides guidance to clinicians with regard to the acute and chronic management of hepatitis (1-888-443-7232, http://www.cdc.gov/hepatitis).

Acknowledgments: The author thanks David M. Cline and Kathy J. Rinnert, the authors of this chapter in the previous edition of this book.