Infection Control Standard Precautions and Isolation

Transcription

1 Infection Control Standard Precautions and Isolation Michael Bell, M.D. Division of Healthcare Quality Promotion Centers for Disease Control and Prevention

2 History of Infection Control Precautions in the United States 1877 Separate facilities 1910 Antisepsis and disinfection Closure of Infectious disease and TB hospitals 1970 CDC Isolation Techniques for use in Hospitals

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5 History of Infection Control Precautions in the United States 1983 CDC Guideline for Isolation Precautions in Hospitals (Disease-specific and category-based precautions including blood and body-fluids) 1985 Universal Precautions 1987 Body Substance Isolation (Mostly focused on worker protection)

6 History of Infection Control Precautions in the United States 1996 Publication of CDC/HICPAC revised guidelines

7 Standard Precautions Constant use of gloves and handwashing (plus faceshields, masks or gowns if splashes are anticipated) for any contact with blood, moist body substances (except sweat), mucous membranes or non-intact skin. Gloves are removed and discarded immediately after completion of a task. Hands are washed every time gloves are removed.

8 Transmission-based Precautions Used in addition to Standard Precautions Airborne Droplet Contact Ø Laboratory and procedure-specific safety

9 Airborne Isolation For infections spread by particles that remain suspended in the air (TB, measles, varicella, and variola). Negative pressure room. Surgical mask on patient. N-95 mask for personnel inside negative pressure room. Isolation room air should not be recirculated in the building. Exhaust air away from people, e.g., off the roof.

10 Droplet Precautions For infections spread by large droplets generated by coughs, sneezes, etc. (e.g., Neisseria meningitidis, pertussis, influenza). Face shield or goggles, and a surgical mask (not N-95) are worn to prevent droplets reaching the mucous membranes of the eyes, nose and mouth when within 3 feet of the patient. Patients should be separated by 3-6 feet, or be grouped with other patients with the same infection/colonization status. Patient should wear a surgical mask when outside of the patient room. Negative pressure room is not needed.

11 Contact Precautions For infections spread by direct or indirect contact with patients or patientcare environment (e.g., shigellosis, C. difficile, MRSA). Limit patient movement. Private room or room shared with patients with the same infection status. Wear disposable gown and gloves when entering the patient room. Disposable gown and gloves should be removed and discarded inside the patient room. Wash hands immediately after leaving the patient room. Clean patient room daily using a hospital disinfectant, with attention to frequently touched surfaces (bed rails, bedside tables, lavatory surfaces, blood pressure cuff, equipment surfaces). Use dedicated equipment if possible (e.g., stethoscopes)

12 Standard Precautions Still the foundation of infection prevention for patients and healthcare personnel New components: Respiratory hygiene and cough etiquette Mask use during special lumbar puncture procedures Added attention to safe injection practices

13 Respiratory Hygiene and Cough Etiquette Part of Standard Precautions Includes: Education Patient behaviors Cohorting Administrative policies and practices

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15 Transmission-based Precautions Contact transmission Direct Indirect Fomites Environmental surfaces Hands

16 Disease Transmission To cause an infection, a pathogenic organism must: Leave original host Survive in transit Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

17 Disease Transmission Leave original host - Incubation period - Symptoms (cough, bleeding, diarrhea) - Clinical specimens Survive in transit Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

18 Disease Transmission Leave original host Survive in transit - Viral envelopes - Spore formation - Environment (humidity, temperature) - Specimen handling Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

19 Leave original host Disease Transmission Survive in transit Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage - Hand transmission - Droplet transmission - Airborne transmission - Fomites - Animal vectors - Mechanical aerosolization

20 Disease Transmission Leave original host Survive in transit - Safety devices to prevent delivery: - sharps containers - biosafety cabinets - negative pressure rooms - vacuum shrouds - Environmental hygiene Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

21 Disease Transmission Leave original host Survive in transit - Personal protective equipment - Hand hygiene Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

22 Disease Transmission Leave original host Survive in transit - Post-exposure prophylaxis - Wound care Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

23 Transmission-based Precautions Droplet and airborne transmission Infectivity time/distance vs environmental factors Obligate or Preferential Opportunistic Predominant mode

24 Transmission-based Precautions Bio-aerosol sources: Patients Aerosol-generating procedures Environmental sources

25 Disease Transmission Pathogens: Leave original host Survive in transit Be delivered to a susceptible host Reach a susceptible part of the host Escape host defenses Multiply and cause tissue damage

26 Survival in transit: Organism factors Environmental factors Time / Distance Droplet size?

27 5 microns Diameter related to unique pathogenesis of pulmonary Mycobacterium tuberculosis infection Terminal alveolar deposition Obligate inhalational transmission Much larger particles can float and are inhaled. Most inhaled particles are not infectious. Most respiratory pathogens do not require terminal alveolar deposition, but infect the upper respiratory mucosa. Opportunistic inhalational transmission?

28 Scientific gaps regarding inhalational infection transmission: 1. Relationship between particle science and infectivity: Time / Distance factor for specific pathogen types Ability of masks and respirators to prevent infection Relative contributions of fit and filtration 2. Risk of infection related to used masks and respirators Direct contact, re-aerosolization

29 Evidence gaps regarding respiratory infection transmission: Relationships between exposure and infectivity: Time / Distance factor for specific pathogen types Environmental effects Infectious dose Point of entry

30 Scientific gaps regarding inhalational infection transmission: Research Agenda Aerobiology Organism-specific measurements Environmental variables Substrate variables

31 Limitations of existing disposable filtering face-piece respirators: Not designed for use in patient care Variable quality of construction and materials Variable fit characteristics Fit-testing required Work of breathing may limit duration of use/compliance Single-use reduces utility in resource-limited settings

32 Characteristics of ideal respiratory protection for healthcare personnel: Prevents infections of bacterial, viral and fungal etiology Provides effective fit for >90% of users Does not require fit-testing Is comfortable to wear for at least one hour Allows wearers to speak clearly Shelf-life of several years Inexpensive Reusable?

33 Negative Effects of Isolation Tarzi et al J Hosp Infect 2001;49:250 Significantly d depressive and anxious symptoms in isolated group Catalano et al S Med J 2003;96:141 Isolated pts had d scores on anxiety & depression scales

34 Negative Effects of Isolation Kirkland et al Lancet 1999;354:1177 HCW s entered rooms of CP patients less often & had less contact with pts Stelfax et al JAMA 2003;290:1899 Isolated pts had more preventable adverse events, expressed greater dissatisfaction with their treatment and had less documented care

35 Expanding our Understanding Systematic assessments of infectivity: By pathogen? By feature(s) of pathogens (e.g., viral envelopes)? Of representative organisms vs. specific? Which organisms warrant specific assessment?

36 Evidence gaps regarding respiratory infection transmission: Current Research Agenda: Aerobiology and surface persistence Organism-specific measurements Environmental variables Substrate variables Improvement of protective equipment for healthcare

37 Is it working? Assessing the effectiveness of preventive measures Simulations alone? Adherence in practice? Active monitoring? Occupational vs home/community exposures?

38 How should data be applied? Revision of respiratory infection transmission according to near vs distant infectivity? Selection of significant pathogens? Alteration of patient placement? Alteration of environmental practices? Alteration of public spaces?

39 Implications for Standard Precautions? Expansion to routine practice? Aerosol-generating procedures Autopsy precedent: MMWR June 11, 2004 / 53(RR08);1-27 Defining aerosol generation?

40 Future directions Improved facility design Natural ventilation Traffic flow and separation Waiting areas Hand hygiene opportunities Facilitation of cleaning