Page 61 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

30 PART 1: An Overview of the Approach to and Organization of Critical Care

patient (for practical purposes, most hospitals require a mask when gowns, masks, and eyewear) should be used when there is a potential
entering the patient’s room). for exposure to these fluids. Following an exposure, the affected skin
Contact precautions should be employed for agents capable of spread should be cleaned immediately with soap and water, and mucous mem-
through direct contact with the patient or contact with contaminated envi- branes should be rinsed with copious amounts of water. Zidovudine
ronmental surfaces or equipment. This is the most frequently employed chemoprophylaxis following needle-stick exposure to HIV-1 decreases
transmission-based precaution in the ICU setting, typically used to transmission risk by 80%. Current guidelines recommend 4 weeks
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prevent the spread of antibiotic-resistant bacteria. Contact precautions of combination antiretroviral therapy with either a two- or three-drug
are generally defined as the use of gloves by all personnel entering the regimen for postexposure prophylaxis, taking into consideration degree
patient’s room and the use of a gown when contact with the patient or of exposure, level of viremia in the source patient, and the potential for
environmental surfaces is anticipated. The use of dedicated equipment resistant virus. For hepatitis C virus, no prophylaxis is currently avail-
(eg, stethoscopes, thermometers) is recommended to prevent this equip- able; exposed workers generally are monitored for 6 months for evidence
ment from transmitting the infectious agent to others. Equipment should of infection. For hepatitis B virus exposure, the immune status of the
be cleaned and disinfected properly before it is used on other patients. The employee should be determined, and hepatitis B immunoglobulin and
risk of nosocomial transmission of MRSA in a neonatal ICU was reduced vaccination should be offered to nonimmune employees.
16-fold by the use of contact precautions. Once the patient on contact
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precautions is discharged from a room, environmental surfaces must be ■ VARICELLA-ZOSTER VIRUS
cleaned thoroughly to eliminate organisms that might persist. Patients with evidence of disseminated varicella-zoster virus (VZV)
■ OCCUPATIONAL HEALTH AND THE ICU infection (eg, chicken pox, varicella pneumonia, disseminated zoster)

Occupational or employee health plays an important role in preventing are capable of transmitting VZV aerosolized particles via respiratory and
shedding virus from noncrusted skin lesions. These patients should be
the spread of highly infectious agents among health care workers. The placed on airborne precautions with negative-pressure ventilation and
hospital’s occupational health department is responsible for screening contact precautions until all skin lesions are crusted. Immunocompetent
employees for contagious diseases and offering employees vaccination hosts with localized zoster can be cared for using standard precautions.
for preventable infections related to health care, particularly hepatitis B Immunocompromised patients with localized zoster should be placed in
virus and varicella-zoster virus. In the case of an exposure to an infec- airborne and contact precautions until disseminated disease is ruled out.
tious agent from a patient, occupational health’s role is to evaluate and, Health care workers without a history of chicken pox or documented
if necessary, treat exposed employees. For particular infectious agents, evidence of immunity should not enter the room of a patient with an
such as exposure of a nonimmune health care worker to varicella-zoster active VZV infection. If a potentially nonimmune health care worker
virus, occupational health has the authority to remove a worker from or patient is exposed, VZV serology should be obtained on that indi-
direct patient care. In smaller hospitals, often a single individual will be vidual. Seronegative personnel should be removed from direct patient
responsible for both infection prevention and occupational health, but contact between 10 and 21 days after the exposure occurred. Likewise,
most large hospitals have two separate departments. The role of infec- if a seronegative patient is exposed to a patient with VZV infection, he
tion prevention is to determine which health care workers were exposed or she should be placed in the appropriate precautions between 10 and
to a contagious agent and refer exposed workers to occupational health 21 days after the exposure. The use of VZV vaccine and varicella-zoster
for follow-up.
immunoglobulin should be considered in both nonimmune exposed
ICU patients and personnel when not contraindicated.

INFECTION CONTROL ISSUES RELATED ■ TUBERCULOSIS
TO SPECIFIC PATHOGENS Tuberculosis is often unsuspected in hospitalized patients, including
■ BLOOD-BORNE PATHOGENS: HIV, HEPATITIS C VIRUS, those admitted to ICUs. This failure of diagnosis has emerged as an

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AND HEPATITIS B VIRUS important contributor to mortality and also may increase the risk
of transmission to hospital personnel. ICU personnel who perform
Because of the need for frequent invasive procedures, the often-urgent procedures that generate respiratory aerosols (eg, endotracheal intu-
nature of these procedures, and the patient population that is served, bation, fiberoptic bronchoscopy, and ventilator management) may be
critical care personnel are at risk of exposure and infection with at particular risk for tuberculosis infection. It should be noted that a
blood-borne pathogens. The most common mechanism by which ICU negative acid-fast respiratory smear does not eliminate the possibility
personnel are exposed is by a percutaneous injury, usually an inadver- of transmission to medical personnel. ICU physicians must maintain
tent needle stick. The risk of infection after a percutaneous exposure a high level of suspicion for tuberculosis and initiate airborne precau-
varies significantly depending on the virus. The risk of infection with tions whenever the diagnosis is considered. Health care workers must
HIV after a percutaneous exposure to infected blood or bloody fluids wear National Institute of Occupational Safety and Health (NIOSH)–
has been estimated to be 0.3%. The risks associated with occupational approved 95% (N95) particulate respirator masks or high-efficiency
mucous membrane and cutaneous exposures to HIV-infected blood particulate air (HEPA)–filtered respirator masks when caring for
appear to be substantially smaller. For hepatitis C virus, the risk of patients with known or suspected tuberculosis. In addition, all ICU
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infection after percutaneous exposure is between 0% and 7%, and for personnel should undergo tuberculin skin testing on hire and at regu-
hepatitis B virus, the risk of developing serologic evidence of infection in lar intervals.
a nonimmune person is 23% to 62%, depending on whether the source
Prevention of infection with blood borne pathogens focuses primarily ■
patient is positive for the hepatitis B e antigen. 85 RESPIRATORY SYNCYTIAL VIRUS
on preventing exposure to blood and offering hepatitis B vaccination on Respiratory syncytial virus (RSV) is a leading cause of bronchiolitis
employment. Practices that minimize the risk of percutaneous injury and pneumonia in infants and small children and is a frequent cause of
(eg, discarding disposable sharp devices in puncture-resistant containers nosocomial outbreaks of lower respiratory tract infections in pediatric
immediately after use) are key aspects of prevention. Precautions should wards. While RSV has been long recognized as a cause of seasonal
also be applied to other body fluids containing visible blood and to cere- infection in children, transmission has been reported in adult patients,
brospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids with significant morbidity and mortality in immunocompromised
and vaginal secretions and semen. Protective equipment (ie, gloves, hosts. The primary mode of transmission of RSV is inoculation of
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