Pandemic Influenza Preparedness

1
Pandemic InfluenzaPreparedness

• The Role of Breathing System Filters

2
Presentation Overview

• Introduction
• Modes of Pathogen Transmission
• The Role of Breathing System Filters
• The SARS Experience
• Where to Use Filters

3
Seasonal Influenza
4
Pandemic Influenza

• Reassortment of animal and human influenza
  strains may produce virus against which humans
  have no immunity, creating the possibility of a
  global outbreak (pandemic).
• Outbreaks may arise quickly and without much
  warning, taxing human resources and equipment
  stockpiles.
• Three such pandemics have occurred in the 20th
  century, resulting in millions of deaths
  worldwide.
• CDC estimates that a pandemic of medium severity
  could cause as many as 45 million cases,
  resulting in over 700,000 hospitalizations and
  200,000 deaths in the U.S. alone.

5
Pandemic Flu Preparedness

• The WHO has stated that despite advanced warning,
  the world is currently ill-prepared to defend
  itself versus an influenza pandemic.
• Planning is critical to success in addressing a
  pandemic outbreak and must include coordinated
  efforts to develop containment policies and
  anticipate manpower and resource allocation.

6
Pandemic Flu Preparedness

• Infection control measures for influenza
• Standard Precautions
• Hand washing
• Use of gloves, face shields, and masks
• Droplet Precautions
• Use personal protective equipment (PPE) when
  working in close proximity to patient
• Airborne Precautions
• Negative pressure rooms
• Use of high-efficiency masks when performing
  aerosol-generating procedures on patients (e.g.
  intubation, aspiration of secretions)

7
Pandemic Flu Preparedness

• Things to Consider
• Immunization requires a preparation phase of 3-6
  months
• Hospital staff will likely be reduced due to
  illness
• High percentage of patients will require
  ventilators
• Shortage of critical medical supplies will result
  (e.g. ventilators)

8
Modes of Pathogen Transmission

• Airborne Transmission
• Droplets
• Droplet nuclei
• Liquidborne Transmission
• Blood
• Patient secretions
• Contaminated water condensate

9
Airborne Transmission
Bacteria originating at a ventilator can travel
as much as 32 feet from their source
Results Avg. Position CFU
Occurrence 1 567 100 2
7 29 3 7 38 4 3 21 5 6 29 6
6 21 7 5 29 8 4 29 9 5 17 10 4 17
11 6 29 12 2 17 13 9 29 14
14 46 15 15 17
15
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IPPB
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IPPB
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2
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1
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14
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15 cm H2O15cpm Nebulizer2.7 x 107 ml Seratia
Marcescens
9
35
Dyer Peterson. 1972. Anesth. Analg. 51516.
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Modes of Airborne Filtration
DIRECT INTERCEPTION Retention of particles that
are larger than the pore structure
INERTIAL IMPACTION Retention of particles due to
their inertia
DIFFUSIONAL INTERCEPTION Retention of particles
based on their diffusionally-increased virtual
diameter
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Airborne Filtration

• Simulated Clinical Filter Efficiency Test

Test filter
Ventilator
Patient
Nebulisation of Mycobacterium chelonae Droplet
size approx. 5µm (Katz et al. Chest 119250)
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Airborne Filtration

• Results

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1

Electrostatic A Electrostatic B
Hydrophobic mechanical
Vezina et al. July 2004 An in vivo evaluation of
the mycobacterial filtration efficacy of three
breathing filters used in anesthesia.
Anesthesiology. 101(1)104-9.
13
Liquidborne Transmission

• Blood Contamination after Intubation

Parker Day. 2000. Anaesthesia 55367-370.
Kanefield et al. Anesthesiology Review.
1990.Incidence of Oral Bleeding After Oral
Endotracheal Intubation. Vol. XVII No. 5
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Patient-to-Patient Transmission of Hepatitis C
Virus

• Case A may have coughed at some stage during the
  procedure, introducing respiratory secretions
  into the reusable part of the anesthetic
  circuitry. This would then have acted as a
  reservoir for the virus which could have been
  transmitted to other patients as droplets via
  minor breaks in their oropharyngeal mucosa. By
  providing a clear airway, the laryngeal mask has
  facilitated transmission.

Chant et al. 1994. NSW Public Health Bulletin
5(5)47-51.
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Filtration of Liquidborne Contaminants
How can gas filters retain liquidborne
contaminants?
1. Choice of Material
Hydrophobic Material
2. Filter Micro-architecture
Fine Porous Structure
Coarse Structure
Not Liquid-Retentive
Liquid Retentive
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Liquidborne Filtration
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1/1 passed
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Prion-Protein9
17
The SARS Experience

• Hong Kong 22 of SARS deaths were among
  healthcare workers
• Taiwan gt90 of the infections occurred in
  hospitals

18
The SARS Experience
Ontario Ministry of Health Guidance Mandated Use
of Pleated Hydrophobic Filters American Society
of Anesthesiologists Recommended the Use of Pall
Filters Taiwan Society for Respiratory Care
Mandated Use of Pall Filters
19
Breathing System Filters

• How can filters interfere with airborne
• and liquidborne microbial route of
• transmission?
• High-efficiency filters prevention
• microbial transmission of infective
• organisms
• from the patient to the ventilator
• from the patient to the environment
• from the ventilator to the patient

20
Where to Use Filters
Ventilation bags
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Where to Use Filters
Transport Ventilators
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Where to Use Filters
Anaesthesia Ventilators
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Where to Use Filters
Oxygen Masks
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Where to Use Filters
Respiratory Therapy/Intensive Care Ventilators
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Thank You forYour Attention!