Infection Control of Aerosol Transmissible Diseases.

Infection Control ofAerosol Transmissible Diseases

Overview Transmission of Communicable Diseases

Principles of Infection Control

Application to Aerosol Transmissible Diseases (ATDs)

Interactive exercises

Resources in packet

The Chain Model of Communicable Diseases

• Infectious agent

• Reservoirs and/or sources

• Portals of exit

• Modes of transmission

• Portals of entry

• Susceptible hosts

The Chain Model of Communicable Diseases• Infectious agent

• Reservoirs and/or sources– human– animal– Environment

• Portal(s) of exit:– Respiratory tract– GI tract– Genital/urinary tract– Breaks in skin

The Chain Model of Communicable Diseases

• Modes of transmission– Direct contact– Indirect contact

• Portals of entry

• Susceptible hosts

Modes of Transmission

• Direct Transmission

Direct Contact Droplet

• Indirect Transmission

Vehicle-borne Vector-borne Airborne

• Vertical transmission (mother to infant)

Infectious Aerosols

Department of Medical Microbiology,Edinburgh University

Transmission of Infections by Respiratory Aerosols• Droplets: land directly on mucosal lining of nose,

mouth, eyes of nearby persons or can be inhaled.• Highest exposures within 3-6 feet.

• Airborne: aerosols become smaller by evaporation; small aerosols (≤ 10 microns) remain suspended for longer periods, if inhaled travel deep into the lungs.

• Contact: Aerosols/ secretions contaminate nearby surface. Touch surfaces can infect self or others.

Relative contribution of three routes varies with agent.

Modes of Transmission viaInfectious Respiratory Secretions• Airborne: tuberculosis, measles, varicella,

smallpox, SARS, avian influenza

• Droplet: meningococcal meningitis, rubella, pertussis, common cold, SARS, influenza*

• Indirect contact: (fomite) RSV, SARS

*Influenza traditionally droplet, increasing evidence for airborne component

Infection Control in aHealth Care Setting

Review

Infection Control in a Health Care Setting

• Basic principles

• Standard precautions

• Transmission-based precautions

• Seasonal influenza in health care settings

• Vaccination of HCWs

• TB screening of HCWs

• Proper donning and doffing

• Choose your PPE

Basic Principles • All body fluids are potentially infectious

(except sweat)

blood and blood-tinged fluids including open-wounds stool, urine, vomit, respiratory secretions, saliva,

semen, vaginal secretions, breast milk, other body fluids such as pericardial and synovial fluids

• Minimize exposure to potentially infectious body fluids

• Infection control measures designed to “break the chain” of transmission

Standard Precautions in Health Care Settings

1. Appropriate hand hygiene

2. Barrier protective equipment:

if splash, splatter, or sprays can be reasonably anticipated

choose appropriate PPE as needed: gloves, gown, mask, eye protection (face shield, goggles)

3. Proper use and handling of patient care equipment

Standard Precautions in Health Care Settings

4. Proper environmental cleaning and disinfection

5. Proper Handling of Linen

6. Adherence to Bloodborne Pathogens Standards

7. Proper patient placement

8. Respiratory Hygiene/Cough Etiquette

9. Safe injection practices

Expanded Isolation Precautions:Transmission-based Standards

When standard precautions are not enough

Additional measures based on mode of transmission

Contact Precautions Droplet Precautions Airborne Precautions

Transmission-Based Precautions: Contact Precautions

For known or suspected infections that represent an increased risk of spread by direct or indirect contact with the patient or the patient’s environment

Transmission-Based Precautions: Contact Precautions

Personal Protective Equipment

Gown & Gloves for all patient interactions

Don PPE on entry, discard before exiting room. (in addition to Standard Precautions)

Examples: MRSA, C difficile, Norovirus, other GI pathogens, RSV, antibiotic-resistant pathogens

Transmission-Based Precautions: Droplet Precautions Single room preferred, no special

ventilation

Patient: Mask if transport necessary. Instruct on respiratory hygiene/cough etiquette

HCWs wear surgical or procedure mask within 6 feet of patient. Eye protection if splash, spray anticipated (in addition to Standard Precautions)

Transmission-Based Precautions: Airborne Precautions

Airborne Infection Isolation Room (AIIR) if available

Patient: Mask if transport necessary (as tolerated).

Health care workers (HCWs):

N95 respirator prior to entry into room, discarded after exit. Higher level respirators for aerosol-gen procedure. Careful attention

to proper putting on & taking off (don/doff) respirator, including seal check.

Hand hygiene before & after don/doff. Alert others if need to transfer

(in addition to Standard Precautions)

Seasonal Influenza in Healthcare Settings

• CDC and CDPH guidelines updated 2010

• Multi-faceted approach

Flu vaccine for HCWs Implementation of respiratory hygiene and

cough etiquette HCWs with ILI stay home Source Control

Seasonal Influenza in Healthcare Settings: Isolation Precautions• Droplet precautions for all patients with

suspect influenza (ILI)

ILI Temp >37.8 C (100 F) plus new cough or sore throat

Ideally, place patients in single room Surgical mask for close patient contact

• Employer may allow N95 during routine care as option

Patient should be transported with surgical mask.

Seasonal Influenza in Healthcare Settings: Isolation Precautions• For aerosol-generating procedures: N95

respirator + standard precautions (gown, gloves, goggles for spray/splash)

• Aerosol generated procedures

Sputum induction, bronchoscopy, elective intubation and extubation, autopsies

CPR, emergent intubation, open suctioning of airways

Vaccination of HCWs

• Protect patients, protect yourself and other HCWs

• CDC recommends

Measles, mumps, rubella (MMR): vaccinate unless documentation of immunity or previous vaccination

Varicella: vaccinate unless documentation of immunity or previous vaccination

Tdap

Yearly influenza vaccination

Hepatitis B: vaccinate unless documentation of previous vaccination

Vaccination of HCWs

• Cal/OSHA ATD & Bloodborne Pathogen Standard

Employer must offer to those who are not vaccinated or immune:

• MMR and varicella vaccination • Tdap• Seasonal influenza vaccination• Hepatitis B vaccination

No cost to employee

Employer must maintain on file: records of immunity, vaccine, or declinations

Tuberculosis Screeningfor Health Care Workers

• Title 22 and Cal/OSHA ATD Standard

• TB screening at hire and then annually for all licensed healthcare facilities in CA (e.g., acute care hospitals, skilled nursing facilities, primary care clinics)

Sequence for Donning PPE

1. Gown

2. Mask or Respirator

www.cdc.gov/ncidod/dhqp/ppe.html

Sequence for Donning PPE

3. Goggles/Face Shield

4. Gloves


Sequence for Removal of PPE1. Gloves


Sequence for Removal of PPE2. Goggles/Face Shield


Sequence for Removal of PPE3. Gown


Sequence for Removal of PPE4. Mask or Respirator


What Type of PPE Would You Wear?

• Giving a bed bath?

Generally none

• Suctioning oral secretions?

Gloves and mask/goggles or a face shield – sometimes gown



• Transporting a patient in a wheel chair?

Generally none required

• Responding to an emergency where blood is spurting?

Gloves, fluid-resistant gown, mask/goggles



• Taking vital signs

Generally none

• Drawing blood from a vein?

Gloves



• Cleaning an incontinent patient with diarrhea?

Gown, gloves

• Taking vitals on a patient with suspect TB?

N95 respirator


Controlling the Spread of Aerosol Transmissible

Diseases in Health Care Settings

Breaking the Chain

Health care and public safety settings

• Unique challenges for control of ATDs

Diversity of job titles and duties Unique “business” of caring for the ill Societal behaviors related to caregiving Exotic and unique exposures Suspension of usual self protection behaviors Emphasis on confidentiality

Aerosol Transmissible Diseases in Health Care and Public Safety Settings

• Droplet

Meningococcal meningitis

Pertussis Mumps Rubella (German

measles) Strep pharyngitis Influenza

• Airborne

Tuberculosis Varicella

(chickenpox) Measles SARS Avian influenza Smallpox Influenza

Hierarchy of Infection Prevention and Control Measures

PPE

Engineering Controls

Protects only the wearer

Elimination of Potential Exposures

Administrative Controls

Protects most

people

Hierarchy of Control Technologies

• Goal is to reduce exposures to a hazard

• Order in which these elements are selected to control exposure is important

Elimination of Potential Exposures Engineering controls Administrative and work practice controls Personal protective equipment/apparel

Elimination of Potential Exposures

• Example: patients with mild influenza like illness stay home

Engineering Controls

• Physically separates the employee from the hazard

• Does not require employee compliance to be effective

• Examples:

physical barriers at triage airborne infection isolation room for patients

with known or suspect airborne infectious diseases

Administrative Controls/ Workplace Practices

• Policies, procedures, and programs that minimize intensity or duration of exposure

Examples: • signs on door of an airborne isolation room• triage, mask symptomatic patient• provide tissues/ masks/hand sanitizer to public

• Standard procedures/ behaviors in caring for patients e.g. hand hygiene, HCW vaccination

• Only as good as enforcement

Personal Protective Equipment• Lowest level of hierarchy - requires employee

compliance for efficacy

• Means higher elements of hierarchy fail to adequately protect employee

• May involve use of gowns, gloves, eye/splash protection or respirators

• Last line of defense

Face Masks vs. N95 Respirators

• Loose fitting, not designed to filter out small aerosols

• Place on coughing patient (source control)

• HCW should wear mask to protect patient during

certain procedures (e.g., surgery, LP)

protect HCW• droplet precautions• Mask + goggles for

anticipated spray/splash

• Tight fitting respirator, designed to filter the air

• Protects the wearer

• HCW should wear when concerned about transmission by airborne route

Reasons for Respiratory Protection• Engineering controls not feasible or sufficient

• Employees must wear N95 respirators (or higher level of protection) in the following circumstances

Entering a room with patient with suspect or confirmed airborne infectious disease

When performing high-hazard (aerosol-generating) procedures on persons with suspect/confirmed airborne infectious disease or influenza

When emergency response employees/others must transport in a closed vehicle, a patient with suspect/confirmed airborne infectious disease

Aerosol-Generating Procedures• Sputum induction, bronchoscopy, elective

intubation and extubation, autopsies

• CPR emergent intubation, open suctioning of airways

What you should do when you hear Ah-choo!

• Likely communicable?

airborne vs. droplet ?

• Choose appropriate source control and PPE

• Reportable Disease? Contact local health department. Some require immediate action

Title 17 reporting requirement

Aerosol Transmissible DiseasesBreaking the Chain• Source control

stay home, isolate or separate mask patient

• Respiratory hygiene, cough etiquette

• Hand hygiene

• HCW protection

• Vaccinate• Droplet – Mask• Airborne- N95 respirator

References

• CDC

2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings http://www.cdc.gov/hicpac/2007IP/2007isolationPrecautions.html

Guideline for Hand Hygiene in Health-Care Settings MMWR 2002; vol. 51, no. RR-16 http://www.cdc.gov/mmwr/PDF/rr/rr5116.pdf

References

• Cal/OSHA

Aerosol Transmissible Disease Standard http://www.dir.ca.gov/Title8/5199.html

Appendix A http://www.dir.ca.gov/Title8/5199a.html

References

• Seasonal Influenza Infection Control Guidelines 2010

CDC: http://www.cdc.gov/flu/professionals/infectioncontrol/index.htm

CDPH http://www.cdph.ca.gov/programs/immunize/Documents/CDPHGuidanceFluPreventionHCS20101105.pdf

Cal/OSHA http://www.dir.ca.gov/dosh/Cal-OSHA_influenza_guidance_11-5-10.pdf

Questions?

Infection Control of Aerosol Transmissible Diseases.

Documents

chain of transmission

ppe slide

packet slide

skin slide

infant slide

airborne component slide

transmission of infections

edinburgh university