N5 Chap 12

• Health care epidemiology


  The study of the occurrence, determinants, and distribution of health and disease within health care settings
• Health care epidemiology


  • The primary focus is on infection control and the prevention of health care-associated infections
  • Includes any activities designed to study and improve patient care outcomes
• Health care-associated infections (HAIs)


  Infectious diseases acquired within health care facilities
• Community-acquired infections


  Infectious diseases acquired outside of health care facilities
• Of approximately 40 million hospitalizations per year in the United States, an estimated 2 million patients (~4% of the total) acquire HAIs
• Most common bacterial causes of HAIs in the United States


  • Gram-positive bacteria: Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus spp., and Clostridium difficile
  • Gram-negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Enterobacter spp., and Klebsiella spp.
• The sources of these pathogens are healthcare professionals, other healthcare workers, visitors, and the patients themselves
• Approximately 70% of HAIs involve drug-resistant bacteria
• The five most common types of HAIs, in descending order of frequency

  • Clostridium difficile-associated diarrhea
  • Urinary tract infections (UTIs)
  • Surgical site infections (also referred to as postsurgical wound infections)
  • Lower respiratory tract infections (primarily pneumonia)
  • Bloodstream infections (septicemia)
• Patients most likely to develop HAIs

  • Elderly patients
  • Women in labor and delivery
  • Premature infants and newborns
  • Surgical and burn patients
  • Diabetic, cancer, and transplant patients
  • Patients receiving treatment with antibiotics, steroids, anticancer drugs, antilymphocyte serum, and radiation
  • Immunosuppressed patients
  • Patients who are paralyzed or are undergoing renal dialysis or catheterization
• Major factors contributing to HAIs

  • An ever-increasing number of drug-resistant pathogens
  • The failure of health care personnel to follow infection control guidelines
  • An increased number of immunocompromised patients
• Additional factors contributing to HAIs

  • Overcrowding of hospitals and shortages of health care staff
  • The indiscriminate use of antimicrobial agents
  • A false sense of security about antimicrobial agents
  • Lengthy and more complicated types of surgery
  • Increased use of less highly trained health care workers
  • Increased use of anti-inflammatory and immunosuppressant agents
  • Overuse and improper use of indwelling devices
• What can be done to reduce the number of HAIs


  • Strict compliance with infection control guidelines
  • Handwashing is the single most important measure to reduce the risks of transmitting pathogens
  • Other means: disinfection and sterilization techniques, air filtration, use of ultraviolet lights, isolation of especially infectious patients, and wearing personal protective equipment (PPE) such as gloves, masks, and gowns whenever appropriate
• Proper handwashing technique


  Steps to follow
• Asepsis


  Without infection
• Medical asepsis


  Precautionary measures necessary to prevent direct transfer of pathogens from person to person and indirect transfer of pathogens through the air or on instruments, bedding, equipment, and other inanimate objects (fomites)
• Surgical asepsis or sterile technique


  Practices used to render and keep objects and areas sterile
• Differences between medical and surgical asepsis

  • Medical asepsis is a clean technique, whereas surgical asepsis is a sterile technique
  • The goal of medical asepsis is to exclude pathogens, whereas the goal of surgical asepsis is to exclude all microbes
• Standard Precautions


  Infection control guidelines to be applied to the care of ALL patients in ALL health care settings, regardless of the suspected or confirmed presence of an infectious agent
• Standard Precautions


  • Hand hygiene; wearing of gloves, masks, eye protection, and gowns; respiratory hygiene/cough etiquette; safe injection practices; lumbar puncture; cleaning of patient-care equipment; environmental control; handling of soiled linens; resuscitation devices; patient placement; and disposal of used needles and other sharps
• Personal Protective Equipment (PPE)


  • Sterile gown, mask, and gloves
• Proper procedure for glove removal


  Steps to follow
• Transmission-Based Precautions


  Used for patients who are known or suspected to be infected or colonized with highly transmissible or epidemiologically important pathogens for which additional safety precautions beyond Standard Precautions are required to interrupt transmission within health care settings
• The three types of Transmission-Based Precautions

  • Contact Precautions
  • Droplet Precautions
  • Airborne Precautions
• Contact transmission


  • Direct contact (i.e. transfer of microorganisms from body surface to body surface)
  • Indirect contact (i.e. transfer of microbes through a contaminated intermediate object)
• Examples of common conditions and diseases requiring Contact Precautions

  • Open wounds—soaked dressings/not well contained
  • Uncontained urine
  • Diarrhea & unable to self-toilet
  • Carbapenem-resistant Enterobacteriaceae (CRE)
  • MDR-Acinetobacter
  • Cystic fibrosis
  • Human metaPneumovirus (HmPV)
  • Respiratory syncytial virus (RSV)
  • Other multidrug-resistant organisms
• Gloves and gowns required always to enter room for conditions requiring Contact Precautions
• Contact Enteric Precautions


  Precautions required for conditions involving diarrhea and enteric pathogens
• Examples of conditions and diseases requiring Contact Enteric Precautions

  • Norovirus (can remove from precautions once asymptomatic for two days)
  • Clostridium difficile infection (remains in precautions for duration of hospitalization)
  • Adenovirus gastroenteritis (if diapered or incontinent)
• Requires gloves and gown to enter room for conditions requiring Contact Enteric Precautions
• Common Conditions and Diseases Requiring Contact Precautions

  • Open wounds—soaked dressings/not well contained
  • Uncontained urine
  • Diarrhea & unable to self-toilet
  • Carbapenem-resistant Enterobacteriaceae (CRE)
  • MDR-Acinetobacter
  • Cystic fibrosis
  • Human metaPneumovirus (HmPV)
  • Respiratory syncytial virus (RSV)
  • Other multidrug-resistant organisms
• Contact Precautions


  Gloves and gowns required always to enter room
• Conditions and Diseases Requiring Contact Enteric Precautions

  • Norovirus
  • Clostridium difficile infection
  • Adenovirus gastroenteritis
• Contact Enteric Precautions


  Requires gloves and gown to enter room, and hands must be washed with soap and water upon exiting room
• Diseases Requiring Droplet Precautions

  • Influenza
  • Meningitis, bacterial (N. meningitidis or H. influenzae)
  • Mumps
  • Pertussis (whooping cough)
  • Rhinovirus
• Droplet Precautions


  • Requires wearing a mask with or without eye shield when entering room and discarding mask when exiting
  • Patient must wear regular mask anytime when exiting room
• Diseases Requiring Airborne Precautions

  • Tuberculosis (active or ruling out)
  • Measles
  • Varicella/Zoster (chickenpox/shingles)
• Airborne Precautions


  • Use N95 mask unless known to be immune
  • Add Contact Precautions if there are any lesions that have not yet ruptured and crusted over
  • Requires negative airflow room and use of N-95 respirator masks
  • Patient must wear a regular mask anytime when exiting room
• Different Types of Respiratory Protection


  • Particulate Respirator (PAPR)
  • Surgical masks
  • Type N-95 Respiratory masks
• Type N95 respirator


  Used when Airborne Precautions are indicated