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Flashcards in Sarah Hepburn microbiology in hospitals Deck (50)
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What is a clean room?

An area with defined environmental control of particulate and microbial contamination
It is constructed and used in a way as to reduce the introduction, generation and retention of contaminants within the area
It's important to remember that a clean room is a controlled area.


In clean rooms, things can contaminate, what 3 things are we trying to minimise the risk of contamination by?

Microbials (including pyrogens)


Particulates are non living, non viable organisms, why is it important to remove them from clean rooms?

Need to remove particulates as non viable articles will form a base for viable organisms to then grown on.


What guide has been published By the MHRA that sets standards of clean rooms?

Orange guide
Annex1, manufacture of sterile products
Standards of clean rooms set out in here


Three main standards/ principles to focus on with clean rooms?

Air quality; air needs to be as pure as possible
Layout of room: need to make sure eg the work station is not right next to the door
Access to room: want to minimise particle contamination when people walk in and out, need to minimise number of people walking in and out when a procedure is taking place.


How do you determine active and passive microbial counts in clean rooms?

Active: number per measured volume
Passive: number during whole session


What are pressure differentials all about in clean rooms?

The pressure of the air in the clean room means that when people walk out of the clean room, dirty air will follow out of the room, the pressure lets dirty air out but doesn't let any air in.


What is grade A activity of sterile products?

Aspeptic preparation of the product and filling into final containers


What is grade A activity of non sterile products?

Filling of products at particular risk of contamination into their final container.


What is grade C and D activity of sterile products?

C is preparation of solutions to be filtered.
D is The storage of ingredients and components.

Remember grade D is activity of a low critical level, ie not as much care has to be taken to ensure sterility, whereas grade A is the opposite!


What is grade C and D activity of non sterile products?

Grade C : preparing solutions at risk of contamination & filling of all products
Grade D: preparation of solutions and components for filling.


There are certain limits for particulate contamination in grade A-D environments, grade D allowing the largest number to be present and grade A allowing the smallest number.
For microbial contamination, what kind of organisms are there limits for?

For bacterial contamination only.
Not viral
Assesses colony forming forming units on air plate, settle plate, contact place and glove plate.


How is air filtered in clean rooms? Name of filter?

Via a HEPA filter
This maintains a positive pressure
And removes 99.997% of particles


What is the pressure differential between rooms of different grades?

10-15 Pascals between rooms of different grades (grades A to D)
Lowest pressure will be grade D room


What's the warning system in clean rooms for?

Air supply, this system checks air flow to make sure air is clean.


What should surfaces in a clean room be like? What other things in the clean room should be considered?

Smooth. No pores. No broken / cracked surfaces.
Minimise amount of ledges, ceiling should contain no seal ie just be smooth all along.
Minimal number of drawers and cupboards
No wood!
Stainless steel trolleys
No sinks allowed in grade A and B areas


Things to consider with equipment in clean rooms?

Should sterilise after reassembly of equipment
Should be easily removable from the clean room so they can be cleaned
Equipment should use a clean water supply that is circulated above 80 degrees.


What does HEPA, as in HEPA filter, stand for?

High efficiency particulate air flow


What are laminar flow cabinets?

They're like a mini clean room with a HEPA filter and air supply
Can get vertical or horizontal laminar flow cabinets!


What are HORIZONTAL laminar flow cabinets for? Which direction does the air flow?

Air flows TOWARDS your operator (safest way, don't want air flowing in your cabinet and brushing past your operator)
They're used for TPN (total parenteral nutrition)
Used for any non harmful substance ( as air flows towards operator)
Used in grade B rooms
Involve a pre-filter to protect your HEPA filter.


What do vertical laminar flow cabinets involve?

Used for HAZARDROUS substances!
Operator must keep hands in cabinet at all times
Curtain of air produced to protect the operator
Siting of these cabinets is important; should not be near the door as this disrupts air flow


Where should vertical laminar air flow cabinets be sited?

In a Seperate, dedicated room
Away from any drafts or ventilation from air conditioning
Away from doors
Away from pedestrian corridors
Away from other cabinets
Present in grade B clean rooms


What are isolators/ barrier technology?

Totally enclosed work spaces
But they're not ABSOLUTE barriers, as product still has to go into them to reach the barrier.
Still some contamination can get let in
Found in grade A environments


Some advantages of isolators?

Cheaper to run
Disturbances in air flow not as critical as with laminar flow cabinets
Better for operator protection due to negative pressure


What are the differences between positive and negative pressure?

Leaks of pressured air less critical in positive pressure
Negative pressure is required to handle hazardous substances (such as cytotoxics, radiopharmaceuticals, certain antibiotics)


Difference between rigid vs flexible film?

Flexible film isolators only suitable for positive pressure
Also problems with cleaning and care of PVC film with flexible film
But flexible will offer less limited workspace.

The rigid design is more robust (sturdy in construct)


Unidirectional (laminar) vs turbulent air flow?

Laminar will minimise air contamination
Air is changed round continuously: high air change rate

Turbulent flow; results in some 'dead spots' ie where no flow is present.
Requires a smaller air filter


What are gauntlets and are they sterile?

Big thick gloves used for handling hot glassware.
They're NON sterile
They don't get changed as often as normal plastic gloves, and the plastic gloves are sterile, and changed before each session


There is a type of isolator called a transfer isolator
It has interlocking doors
different types will effect these isolators siting

When cleaning an isolator it must not effect the integrity of the isolator (ie must not effect it's actions)
You disinfect using liquids
Sterilise using gas such as H2O2


Clothing of operators of these processes will be appropriate to the process they're carrying out and for the grade of the working area.


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