Small update on using KING HEPA filters in the era of COVID and EMS

1. HEPA Filter Use

3. Objectives
• Differentiate a respiratory HEPA filter from a
HME
• Describe the benefits of a HEPA filter in
patient care
• Describe how to use a HEPA filter in a wide
variety of patient care situations
• Describe precautions to take during
aerosolization procedures.

4. CDC recommends
• The CDC recommends the use of a
HEPA filter with BVMs to filter
expired air from suspected
influenza and coronavirus patients.
These filters will fit between the
BVM’s valve and the mask or ET
tube.

5. HEPA Filter?
Filters in patient ventilation does three things:
• They protect the patient from any sort of
airborne filth which might be blowing
around in the gas supply systems or the
ambient air.
• These filters protect the delicate innards of
the ventilator from the corrosive swamp gas
being exhaled by the patient.
• The filters protect the intensivist and their
co-workers from exhaled pathogens and
clouds of nebulized medications which did
not make it into the patient.

6. Contamination?
From the ambient air to the patient
• Bacteria from the environment
• Viruses from the environment
• Condensed water
• Particles and dust from supply
pipes, O2 tanks, and BVMs
From the patient to the ambient air…
• Microbial pathogens
• Viruses
• Bacteria
• Water droplets
• “Bio Film”
• Nonstandard expired gases (eg.
anesthetic gases)
• Residual nebulized medications

7. Key points to
remember
• Expired particles from an intubated patient are
usually ~ 0.3-1.0µm in diameter, and there
may be up to 2500 particles per breath.
• So, the use of a HEPA filter does not
preclude the need for a N-95 mask on a
provider, but it does help.
• PEEP is the most important determinant of
expired particle density
• more PEEP means more expired particles
• Same principle applies to CPAP.
Citation: Wan G-H, Wu C-L, Chen Y-F, Huang S-H, Wang Y-L,
Chen C-W (2014) Particle Size Concentration Distribution and
Influences on Exhaled Breath Particles in Mechanically
Ventilated Patients. PLoS ONE 9(1): e87088.
https://doi.org/10.1371/journal.pone.0087088

8. Lots of different filters, most work the same.

9. HME or Bacterial / Viral Filters?
• Heat-Moisture Exchangers (HME) are simple paper filters
designed to collect warm moisture during exhalation and use
that to rewarm and humidify the next breath. They look very
similar to Bacterial/Viral Filters but have no infectious control
function.
• Bacterial/Viral Filters are specifically designed to
reduce/eliminate bacterial and viral pathogens.
• Think of them as a N-95 mask for the ventilation circuit or
BVM
• Like an N-95, they only work if used properly.
• Do they work to decrease spread of viruses like coronavirus and
influenza?
• Yes, when used correctly they reduce viral load in exhaled
air by ≥99.9995%
Heuer, J. F., Crozier, T. A., Howard, G., & Quintel, M. (2013). Can breathing circuit
filters help prevent the spread of influenza A (H1N1) virus from intubated
patients? GMS Hygiene and Infection Control, 8(1).
https://doi.org/10.3205/dgkh000209

10. HME or
Bacterial /
Viral Filters?

11. HME or
Bacterial /
Viral Filters?
PEEP Valve

12. Practical Use

13. Deployment
of HEPA
Filters
• THREE per ambulance
• One in each orange airway bag (Two per ambulance)
• One in each Vent bag Next to CPAP masks
• One per one man unit
• One per QRU
• If possible, try to use the same filter from QRU BVM
through the vent to the hospital.
• We will replace filters used by the QRUs on calls just like
BVMs, etc
• Additional in stock

14. In the
package
Keep in package until use.
Exposure to moisture degrades the filter over
time.

15. Standard
connections

16. Filter on an
ET Tube

17. With an O-
TWO E600
Vent Circuit

18. With ETCO2

19. On a CPAP
mask

20. With a neb (Use a mask)
This Photo by Unknown Author is licensed under CC BY-SA

21. Rationale
• In standard nebulizers, up to 45% of the medications
are never absorbed by the patient.
• Some is still “inside” the patient in the “dead air
space” and is therefore contaminated.
• The “RISK” is the exhalation directly from the patients’
mouth of nebulized mist more so than the neb
• Some risk of bio-contaminated matter in the reservoir
• Exhalation filtration with a surgical mask reduces this
exposure significantly
• Providers still need to wear PPE
• Put a mask on the patient whenever practical
Citation: Ari, A., Fink, J. B., & Pilbeam, S. P. (2016). Secondhand aerosol exposure
during mechanical ventilation with and without expiratory filters: An in-vitro
study. Indian Journal of Respiratory Care, 5(1), 7.

22. Remember…
• All respiratory therapy has potential to create aerosols
but high flow therapies, when properly applied, are low
risk compared to NIPPV and advanced airway
management.
• When adding a surgical style mask over high flow
therapies (HF Nasal Cannula, NRB, or Neb) to catch the
exhaled gasses and particulate, the mask reduces the
exposure risk to that of low flow therapies (i.e. low flow
Nasal Cannula)
• Minimizing mask leak (fitting mask to face) is
essential.
Citation: Leonard, S., Volakis, L. I., DeBellis, R., Kahion, A., Mayar, S., & Dungon II, G. C. (2020, March 25). COVID-19
Transmission Assessment Report. Vapotherm - Mask-Free NIV for Spontaneously Breathing Patients.
https://vapotherm.com/blog/transmission-assessment-report/

23. Are there any precautions?
• Cases of filter obstructions have been reported, generally due to
excessive secretions, blood in trauma patients or excessive water
condensation.
• This can lead to high-airway pressures and inadequate
ventilation.
• In one case report, an obstructed HEPA filter prevented
ventilation and had to be exchanged.
• Always be prepared to swap to a new HEPA filter if the patient
becomes difficult to bag. This will be most common with massive
blood, vomit, or other secretions in the tube.
• Consider this a possible “obstruction” in the “D.O.P.E.S.”
trouble shooting checklist.

24. Are there any
precautions?
• A partially clogged HEPA filter may
result in air trapping
• This can lead to barotrauma,
pneumothorax, and CO2 retention.
• Consider this a possible reason
for “stacked breaths” in the
“D.O.P.E.S.” trouble shooting
checklist.
• Always be prepared to swap to a
new HEPA filter.

25. Do not forget…
Basic Hand
Hygiene and
basic PPE will
protect more
providers and
patients than
100 HEPA filters.

26. Questions?
•Contact your
training
officers…that is
what we are
here for.