Isolation Room Systems
MICROCON® ExC-BB For Hospitals
and Healthcare Facilities in creating Isolation
Rooms.
Negative Pressure Isolation
Rooms and Positive Pressure Isolation Rooms.
Clean air and the control of airflow have become
vitally important in the control of airborne diseases,
particularly TB and Avian Bird Flu Influenza H5N1.
The increase in TB cases, particularly drug resistant
strains, has caused the CDC to write a guideline
for Isolation Rooms in controlling TB in Health
Care facilities. These Isolation Room guidelines
are now being enforced by OSHA. JCAHO has followed
it in their process and is looking for compliance
as part of certification. These agencies take this
very seriously.
There is
a greater need in the Third World Countries for
Negative Pressure Isolation Rooms for TB
and Preparedness of Pandemic Avian Bird Flu Influenza
H5N1.
An even more measureless need for Positive Isolation
Rooms for treating HIV infection
TB kills more adolescents
and adults than any other single infection. It is
also a leading cause of death among women. Almost
2 billion people are infected with the disease worldwide
or nearly one-third of the world's population. M.
tuberculosis is carried in airborne particles, or
droplet nuclei, that can be generated when persons
who have pulmonary or laryngeal TB sneeze, cough,
speak, or sing. The particles are an estimated 1-5
um in size, and normal air currents can keep them
airborne for a prolonged time periods and spread
them throughout a room or building. Infection occurs
when a susceptible person inhales droplet nuclei
containing M. tuberculosis, and these droplet nuclei
traverse the mouth or nasal passages, upper respiratory
tract, and bronchi to reach the alveoli of the lungs.
Thus creating the demand and need of Negative Pressure
Isolation Rooms for risk reduction to all health
care personnel in medical care facilities.
Immunocomprised persons have a greater risk for
the progression of latent TB infection to activate
TB disease; HIV infection is the strongest known
risk factor for this progression.
Transmission of M. tuberculosis
is a recognized risk in health care facilities.
The magnitude of the risk varies considerably by
the type healthcare facility in which the HCW’s
(Health Care Workers) occupational group, the area
of the health care (healthcare) facility in which
the HCW works, and effectiveness of TB infection-control
interventions.
Biological Controls' MICROCON® units for use
in Negative Pressure Isolation Rooms and Positive
Pressure Isolation Rooms
An effective TB infection
control program requires early identification, isolation
rooms, and effective treatment of persons who have
active TB.
The second level of the hierarchy
is the use of engineering controls to prevent the
spread and reduce the concentration of infectious
droplet nuclei within the isolation room. These
controls include a) direct source control using
local exhaust ventilation, b) controlling direction
of airflow within the isolation room to prevent
contamination air in areas adjacent to the isolation
room and the infectious source, c) diluting and
removing contaminated air via general ventilation,
and d) air cleaning via air filtration or ultraviolet
germicidal irradiation (UVGI) all within the isolation
room.
In the early 90's, with the
advent and resurgence of TB, Biological Controls
started designing and building MICROCON® equipment
specifically for airborne infection control applications.
With the exception of some localized problems, the
disease has not reached epidemic proportions in
the US. In 1994, the Centers for Disease Control
and
Prevention (CDC) adopted Guidelines for Preventing
the Transmission of TB in Health Care Facilities
(Guidelines) in an attempt to minimize the risk
that TB might be passed from patients to healthcare
workers, other patients and visitors. The Guidelines
also recognized that the greatest risk of TB transmission
exists with undiagnosed TB cases. The Guidelines
also recognizes that a complete program to control
TB must include engineering controls to reduce the
concentration of infectious droplet nuclei in the
air. The Guidelines impose a rather comprehensive
list of features, which are to be designed into
Airborne Infectious Isolation Rooms both Negative
and Positive, with Minimum Standards.
Biological Controls offers
an array of Isolation Room products which are designed
to:
- Reduce risks of transmission
of disease
- Provide compliance with
all regulations for an isolation room
- Eliminate the need for
expensive renovations to HVAC systems connect
to the isolation room
All of Biological Controls’
filter units comply with CDC Guidelines, and
are FDA 510K certified.
“An FDA 510K certification is mandatory for
air purification systems in hospital use!”
Especially for creating
an isolation room.
The products include those for removal of airborne
pathogens, creation of negative pressure isolation
rooms, monitoring of pressure differential conditions
and enclosures for use in performing high risk procedures
or holding patients who are known or suspected to
be at risk of transmitting airborne diseases. Knowing
that this type of equipment is performing to specifications
is very difficult, since the particles being removed
are invisible to the naked eye, or the pressure
differential cannot be sensed. For these reasons
our products have been independently tested and
products like the ACCUSTAT® were designed to
help reassure isolation room compliance.
Each isolation room product
is designed to perform a specific function in meeting
the CDC Guidelines engineering controls. Integrating
them into a system provides an inexpensive, yet
superior performance as an alternative to standard
engineering retrofits.
The requirements for isolation
rooms are not specific to TB since isolation room
precautions are required for a variety of other
infectious diseases (e.g., varicella zoster, rubeola).
Patients with TB should be isolated in a room where
the air pressure is negative to the corridor, resulting
in inward directional airflow back into the isolation
room.
Health care (healthcare)
facilities should determine the number of isolation
rooms they require. If several isolation rooms are
necessary, consideration should be given to locating
these rooms in one area of the facility. Health
care facilities should also liaison with regional
and public health authorities to determine the number
of isolation rooms required for the region outlines.
Isolation Rooms & Pressurization
Control
Isolation Room Systems can be classified in
two (2) basic categories:
• Negative Pressure Isolation Rooms: The relative
air pressure difference between two areas in a health
care (healthcare) facility. A room at negative pressure
has a lower pressure than that of adjacent areas,
which keeps air from flowing out of the room and
into adjacent rooms or areas, preventing airborne
transmission.
Viruses Examples: Measles, Mumps, Chicken
pox, Influenza, and suspected or proven pulmonary
or laryngeal Type M. tuberculosis.
• Positive Pressure Isolation Rooms:
Greater air pressure in the isolation room than
in the adjacent corridor or anteroom. To prevent
transmission from the outside environment to profoundly
immunosuppressed persons/patients.
Fungi Spores Examples:
Prevention of aspergillosis in bone-marrow transplant
recipients. Anthrax, Eryptoccus, Micropolyspora
The intent of the CDC in
developing guidelines that they be readily achievable
by community health care institutions with minimal
funds. Anyone who has training in liability issues
as they relate to health care knows that codes and
standards are recognized by the legal community
as minimum requirements, so creative interpretation
of the Guidelines to minimize cost of implementation
is strongly discouraged.
To be entirely successful,
a project to develop a new Isolation Room in any
institution should include early involvement of
the nursing staff who will manage the room, the
Infection Control Department, and the maintenance
staff.
The MICROCON® ExC-BB
Important Engineering Features for Isolation Rooms
The MICROCON® ExC-BB has an isolation room airflow
minimum of 12 air changes per hour. The Guidelines
do not specify if the supply airflow or the exhaust
airflow should equal 12 air changes per hour, but
making the supply air flow equal to 12 air changes
per hour is the most conservative approach for an
Isolation room.
Therefore, based upon that premise, for
most normal capacity rooms the MICROCON ExC-BB is
more than sufficient to satisfy the isolation room
minimum 12 ACH requirement. Knowing the specific
parameters of room volume, supply and exhaust
air capacity, will better determine the
exact require and number of air changes that can
be created to assure isolation room compliance using
the ExC-BB system.
CDC Guidelines regarding
isolation rooms states that the exhaust airflow
volume should exceed the supply airflow volume by
approximately 10% or 50 CFM, whichever is greater,
to maintain a negative pressure within the Isolation
Room with respect to surrounding areas. MICROCON®
ExC-BB has the capacity to comply with this CDC
isolation room recommendation. Negative pressure
will cause an inward flow of air into the Isolation
Room when doors are opened, preventing the migration
of bacteria to the surroundings. The location and
process of air intake and exhaust was deemed critical
to its functionality and uniqueness. The path of
the air being from the undercut of the door sweeping
to the intake of the MICROCON® unit in the ceiling
of the isolation room.
When HEPA filtration is utilized
as a method of air cleaning it supplements other
recommended ventilation measures. HEPA filters remove
a minimum of 99.97% of particles 0.3 microns and
larger. TB bacteria have a rod-like shape with a
minimum diameter of 0.5 microns. All air is HEPA
filtered by the MICROCON® ExC-BB within the
isolation room before exhaust.
HEPA filters by design are
resistant to the passage of air. Therefore, proper
sealing of HEPA filters is essential to maintaining
the integrity of the system. Any bypass of unfiltered
air compromises the system. The CDC Guidelines for
Hospital Isolation Rooms address the need for adequate
sealing in health care (healthcare) air purification
systems. Also a means of assessing the loading of
the HEPA filter, is necessary. Biological Controls
manufacturer of the MICROCON® ExC-BB, has all
products equipped with a minihelic gauge (a pressure
differential gauge designed to monitor filter life
expectancy). As the filter becomes clogged with
contaminants (thereby increasing resistance) the
less filtered air is delivered at rated flow. HEPA
filters don’t become less efficient with use
only their airflow delivery diminishes with use.
The pressure reading on the gauge is an objective
means to determine the filter loading and degree
of resistance on the isolation room system. It is
a much more accurate means than the more commonly
used, less costly and less accurate filter warning
light.
Pressure measurement for variable
volume supply and exhaust systems in the isolation
room is critical. If variable volume is used, it
is imperative that accurate, reliable controls must
be used to sense the pressure differential between
the patient isolation room and the surroundings
and adjust the fan operation to maintain the desired
pressure differential.
The MICROCON® ExC-BB is
equipped with a 2 (high & low) speed fan control.
This will allow precise calibration of exhausted
air. The isolation room unit will deliver between
300 to 450 CFM of air. A minihelic gauge monitors
filter performance and alerts you to filter replacement
or a malfunction. A lighted switch advises when
the unit is operating.
CONSTANT OPERATION
Circumstances may exist where negative pressure
cannot be constantly maintained within an isolation
room or where cost or time constrains in creating
a negative pressure isolation room environment are
prohibitive. A combination of the ACCUSTAT®
and the MICROCON® ExC-BB for this application
are ideal.
The isolation room system
is not permanent so that it can be easily installed
for a short period of time if necessary. To maintain
constant negative pressure within a room the MICROCON®
ExC-BB or EX-BB is ducted out and the ACCUSTAT®
is installed by attachment to the wall outside the
isolation room. By determining the room air supply
volume and exceeding that by at least 10% or 50
cfm negative pressure should be constantly maintained
while the ACCUSTAT® confirms compliance.
Further the MICROCON®
ExC-BB meets the CDC Isolation Room Guidelines specifying
a minimum pressure differential of 0.001 inches
w.g. (water gage) or an inward velocity of 100 feet
per minute for the Isolation Room. Our ACCUSTAT®
isolation room monitors equipped for differential
pressure measurement should be utilized for this
application. Our ACCUSTAT® Isolation room pressure
monitors are designed to allow you to continually
know the pressure differential status of any isolation
room whether it be negative or positive and maintain
compliance with all regulations.
The Isolation Rooms should
be well sealed from the surroundings to help maintain
the pressure differential. Penetrations through
walls must be sealed, and drywall or ceilings impervious
to air should be used.
Swinging doors are easier to seal than sliding doors.
Since the ExC-BB is recirculating air, UV ultra
violet irradiation is recommended in combination
with the ExC-BB or our ExC-BUV as an extra precaution
of irradiation especially for infectious viruses.
e.g. Mumps, Measles,
Chickenpox, and influenza.
Ultraviolet (Ultra Violet)
Ultraviolet germicidal (UV) radiation in the 254-nanometer
wavelength has proven effective in killing most
types of airborne bacteria and viruses. Coupled
with a high efficiency filter cell upstream of the
four UV lamps the germicidal effectiveness is greatly
enhanced.
Monitor Negative Pressure
Isolation Rooms
ACCUSTAT® gives you an accurate digital readout
of the pressure differential in the isolation room
being monitored and the adjoining area. Ideal placement
should be on a wall outside the isolation room to
be monitored with a sampling tube directed into
the isolation room. The ACCUSTAT® monitor will
record and clearly display the differential pressure
reading on the digital readout display to within
.001 inches of static pressure for easy monitoring
outside the room. Providing a visible and/or audible
alarm when low air pressure is sensed, while incorporating
a time delay to allow staff to enter the isolation
room without activating the signal. If an Anteroom
is provided with the Isolation Room, the Guidelines
require that the Isolation Room be maintained at
negative pressure with respect to the Anteroom.
The pressure relationship between the Anteroom and
the corridor is negative.
NO FALSE ALARMS
The ACCUSTAT® is designed with a visible or
audible alarm that activates when the room drops
below a predetermined set point. There is a 1 minute
delay cycle designed to avoid nuisance alarms due
to a temporary condition existing. This situation
might arise when a healthcare worker or staff enters
or exits the isolation room momentarily. The LED
will light indicating negative pressure has been
reached as will the digital readout record, the
actual increase in pressure, but the alarm well
not sound for that one minute grace period. But,
after a minute if the room pressure has not returned
to negative pressurization it will activate the
sound alarm that an unsatisfactory condition exists.
The alarm feature can also be muted.
REMOTE MONITORING
By connecting an optional cable which directly attaches
to the sensor a remote monitoring station can be
created to establish a multiple monitoring panel
that identifies each ACCUSTAT® location and
the status of the isolation room.
The ACCUSTAT® acts as
a sentinel to provide continuous monitoring of the
isolation rooms. Having this tool offers you a status
report on an ongoing basis that you are in compliance
with the standards and the codes and affording the
protection required for patients and staff alike.
CREATING POSITIVE PRESSURE
ISOLATION ROOMS
Having greater air pressure in the positive isolation
room than in the adjacent corridor or anteroom.
To prevent transmission from the outside environment
to profoundly immunosuppressed persons/patients.
In creating a positive isolation
room the ExC-BB should be installed (ceiling mounted)
outside the positive isolation room. The supply
duct must be attached to the downstream exhaust
connection of the unit and be directed into the
positive pressure isolation room through a ceiling
mounted diffuser. This is additional
air and thereby positively pressurizing the room.
Install a self-closing door in positive pressure
rooms, considering the
direction door swing in relationship to room pressure.
CREATING A COMPLETE SYSTEM
The ACCUSTAT® coupled with the MICROCON®
ExC-BB will provide a very useful and critical function
at a fraction of the cost and time of major renovations
to the HVAC system. The installation need not be
permanent and can be relocated and repositioned
at anytime wherever needed. However, it alone isn’t
suitable as a means to allow for the required internal
air changes to occur since its primary function
is to clean exhausted air. Once established, the
negative pressure isolation room is designed primarily
to protect staff and patients outside the room by
“containing” possible infectious airborne
particulate within the isolation room. To complete
the process of affording protection to healthcare
workers and care givers who must enter the isolation
room on an ongoing basis the MICROCON® 400/800
Mobile Hospital Air Purification System or the MICROCON®
WallMAP should be utilized.
These will create the ventilation,
dilution, filtration and irradiation “within”
the isolation room that the CDC recommends to enhance
and complete the process. By allowing for the maximum
number of air changes to take place and for the
creation of consistent air currents and patterns
to be established inside the isolation room.
GLOSSARY For Negative
and Positive Isolation Rooms
This glossary contains terms (and abbreviations)
used in the guidelines, as well as terms that are
frequently encountered by persons who implement
infection control programs. The definitions are
those that are most applicable for communicating
with health professionals.
ACH Air changes per hour
Aerosol The droplet nuclei that
are expelled by an infectious person (by coughing
or sneezing for example). These droplet nuclei can
remain suspended in the air and can transmit an
infection to other persons.
Air Changes The ratio of the volume
of air flowing through a space within a period of
time (that is, the airflow rate) to the volume of
that space (that is, the room volume). This ration
is usually expressed as the number of air
changes per hour (ACH)
Air Diffuser An air outlet discharging
supply of air in various directions and planes.
Air Mixing The degree to which
air supplied to an isolation room mixes with the
air already in the isolation room usually expressed
as a mixing factor. This factor varies from 1 (for
perfect mixing) to 10 (for poor mixing), and it
is used as a multiplier to determine the actual
airflow required. (The recommended ACH multiplied
by the mixing factor equals the actual ACH)
Anteroom A
small room leading from a corridor to an isolation
room. This room can act as an airlock, preventing
the escape of contaminants from the isolation room
into the corridor.
Aspergillosis Infection with or
disease caused (as in poultry) by molds.
ASHRAE American Society of Heating,
Refrigerating and Air-Conditioning Engineers. This
professional body develops standards for building
ventilation.
Bronchoscopy A procedure for examining
the respiratory tract. An instrument (a bronchoscope)
is inserted through the mouth or nose and into the
trachea. The procedure can be used to obtain diagnostic
specimens.
Computational Fluid Dynamics Computer-aided
fluid modeling. Airflow patterns and air streams
are calculated by solving fundamental fluid mechanics
equations of laminar and turbulent flow, such as
the flow pattern and distribution of wind blowing
over a building.
Differential Pressure Gauge A pressure
gauge that will display the difference in pressure
between one port on the gauge and the other. It
is normally placed to measure the difference in
pressure between two rooms. Displacement Diffuser
An outlet grill that creates displacement diffusion.
Displacement Diffusion A directional
airflow pattern that provides a single-pass air
stream. The air flows from the source, over the
designed target area, to exhaust with the least
mixing, therefore creating as little turbulence
as
possible.
Droplet Nuclei Microscopic particles
(1-5 um in diameter) produced when a person coughs,
sneezes, shouts or sings. An infectious tuberculosis
patient can produce droplet nuclei bacilli and remain
suspended in the air currents in the
room.
High Efficiency Air (HEPA) Filter
A filter is capable of removing 99.97% of particles
sized 0.3 um in diameter. Filters may be used in
ventilation systems to remove particles from the
air. Immunosuppressed Immuno-compromised A state
in which the immune system is not functioning normally
(for example severe cellular immunosupression resulting
from HIV infection or immunosuppressive therapy).
Infection The condition in which
organisms capable of causing disease (for example,
M. tuberculosis) enter the body and elicit a response
from the hosts immune defenses. Tuberculosis infection
may or may not lead to clinical disease. Infectious
Capable of transmitting infection
Negative Pressure Isolation Rooms
The relative air pressure difference between two
areas in a health care facility. An isolation room
at negative pressure has a lower pressure than that
of adjacent areas, which keeps air from flowing
out of the isolation room and into adjacent rooms
or areas.
Nosocomial Infection A hospital
acquired infection.
Positive Pressure Isolation Rooms:
Greater air pressure in the isolation room than
in the adjacent corridor or anteroom. To prevent
transmission from the outside environment to profoundly
immunosuppressed persons/patients. Recirculation
Ventilation in which all or most of the air that
is exhausted from an area is returned to the same
area or other areas of the facility.
Self Closing Door A door with a
self closer (for example, a simple, mechanical hydraulic
lever type closer)
Sputum Induction A method of obtaining
sputum from a patient who is unable to cough up
a specimen spontaneously. The patient inhales a
saline mist, which stimulates a cough from deep
within the lungs.
Transmission The spread of an infectious
agent from one person to another. The likelihood
of transmission is directly related to the duration
and intensity of exposure to the pathogen.
Virulence The cause of a microorganism
to cause disease.
VRE Vancomycin resistant enterocci
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