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
When HEPA filtration is utilized as a method of air cleaning it
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
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
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.
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
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.
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
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
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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