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decon > sterilisers > Flashcards

sterilisers Flashcards

1
Q

what is the guidance document?

A

SHTM 2010

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2
Q

daily info for sterilisation

A 
date
time started
operator
cycle no
sterilisation temp
daily tests performed
sterilisation successful
machine identified cycle completed successfully
Type B - Bowie Dick successful
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3
Q

who carries out the daily and weekly tests?

A

on site staff

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4
Q

temp

A

134-137 degrees

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5
Q

time

A

min hold time 3mins

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6
Q

pressure

A

pressure equivalent gauge (from atmospheric) 2.05 to 2.35 bar
pressure equivalent absolute (from absolute 0) 3.05 to 3.35 bar

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7
Q

do all sterilisers achieve the same temp and pressure?

A

yes

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8
Q

daily tests

A

wipe door seal with clean, disposable, damp, non-linting cloth and carry out any other checks required by the manufacturer, check seal for damage/contamination

check load carrier and chamber for damage/debris/clean

fill and drain water reservoir

when switching power on, check that the ventilation louvers are not covered to avoid overheating

if recommended by the steriliser manufacturer, preheat the steriliser chamber before performing daily tests

record completion of the daily checks in the steriliser logbook

Type B: Bowie Dick (steam penetration) test

record daily sterilisation temps

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9
Q

which extra daily test is required for type B sterilisers?

A

Bowie Dick (steam penetration) test

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10
Q

sterilisation

A

a process undertaken to render a steriliser load sterile

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11
Q

sterile

A

condition of a medical device that is free from viable MOs

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12
Q

weekly tests

A

Type B - air detector function test and air leakage test
ACT
daily tests
weekly safety checks

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13
Q

weekly safety checks

A

examine door seal for signs of wear or damage

examine security and performance of the door safety features inc the hinges and locking mechanism as detailed in the MIs

if a fault is detected in the door seal or safety features, ensure this is corrected before carrying out weekly tests or using the steriliser

record satisfactory completion of the weekly safety checks in the steriliser logbook

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14
Q

type N steriliser - how does it work?

A

‘gravity displacement’
air passively displaced by steam
purified water introduced to the chamber and heated
as it boils and turns to steam, the chamber pressure increases

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15
Q

what instruments can be processed in type N?

A

rigid steel solid instruments

no wrapped/channeled/lumened

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16
Q

stages in type N

A

air removal - heating time
sterilising - holding time
condensing - cooling time

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17
Q

what instruments can be processed in a type B?

A

wrapped and non-wrapped (make sure not to damage wrappings)
channelled and porous instruments
porous loads e.g. cotton swabs

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18
Q

loading recommendations

A

no overlapping/shadowing
do not overload machine
assemblies should be disassembled beforehand
utilise the available basket/load carrier

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19
Q

type B - how does it work?

A

porous load/vacuum capable
has active air removal creating a vacuum in the chamber in its initial stage
so steam can contact all surfaces of device
because there is no air in the chamber, the vacuum rapidly draws the steam in from the generator
after sterilisation the machine draws another vacuum for drying, allowing water to vapourise at lower temps

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20
Q

B type - after processing

A

wrapping intact - ‘sterile’ at point of use

can store in env controlled atmosphere that is free from contaminants and moisture

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21
Q

N type - after processing

A

‘sterilised’
wrap as soon as remove from steriliser and transport to procedure room
either for immediate use or for non-sterile storage, transport and application

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22
Q

why should instruments be left to cool down after first?

A

if put hot instrumentation into transport box might cause condensation to build up, potentially damaging wrappings

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23
Q

for sterilisation of wrapped goods what must the residual gas not exceed?

A

3.5 ml per 100ml of condensed steam

air detector incorporated as a safety device to monitor the adequacy of the air removal process

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24
Q

what is residual gas?

A

remaining air and gases carried in the steam after the air removal stage

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25
Q

type S

A

products specified by the manufacturer of the steriliser inc non-wrapped solid products and ≥1 of the following: porous products, small porous items, hollow load products type A, hollow load products B, single wrapped products, multiple layer wrapped products

vacuum pump/some other active method to remove air from the chamber and load

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26
Q

what should dental handpieces be sterilised using?

A

a vacuum process

type S

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27
Q

obligations under H+S and Consumer Protection Act

A

ensure equipment:

  • complies with safety requirements
  • installed and maintained appropriately
  • validated and routinely tested
  • operated only in accordance with MIs and by properly trained operators
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28
Q

water and steam quality

A

good quality water to make good quality steam

water low in minerals to prevent depositing minerals onto the instruments (limescale) and making them harder to clean

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29
Q

waters recommended by manufacturers for use in sterilisers

A 
= pure water
Reverse osmosis
distilled
sterile
deionised
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30
Q

basic stages of operation of Type B

A 
1 - air removal (negative pulsing)
2 - steam admission (positive pulsing)
3 - equilibration
4 - sterilisation
5 - drying
6 - air admission (0.2micron fitted inlet)
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31
Q

type B : 1 - heating up of water and air removal

A

water enters an external boiler known as a steam generator to a pre-determined level from the clean tank

heating element switched on (generator heating water)

machine is pulling a pre-determined vacuum (neg pressure)

as water reaches bp, steam generated. Element stays on until the steam reaches sterilising temp

once vacuum achieved to a pre-determined level the steam generator injects steam - 3 times (neg pulsing)

on 3rd injection of steam vacuum cuts off and the steam is allowed to build up in stages (positive pulsing) to the sterilising temp and pressure

32
Q

type B: 2 - sterilising

A

once all air removed and temp/pressure achieved it is held for a holding time (min 3mins)
sterilising temp controlled by a combination of pressure transducers and sump and chamber temp sensors
at end a valve opens to allow the condensate steam to enter the dirty tank

33
Q

Type B: 3 - drying

A

B unlike N has a proper drying stage
pulling a vacuum whilst keeping the chamber hot - remove steam
some sterilisers do vacuum pulses at this stage whilst others only pull the one deep vacuum
negative pressure

34
Q

Type B: 4 - cooling (air admission)

A

after a predetermined time the vacuum is switched off and the chamber allowed to cool
when the chamber reaches atmospheric pressure and a set temp (typically 80 degrees) the door is unlocked and can be opened

35
Q

mass

A

amount of matter an object contains (kg)

36
Q

weight

A

force caused by gravity on an object (N)

- weight of a mass 1kg approx 10N

37
Q

pressure

A

force acting normally per unit area

1Pa = 1N/m2

38
Q

atmospheric pressure

A

often given in millibars where standard sea level pressure defined as 1000mbar = 1 bar
when we speak about vacuum for sterilisation normally use mbars
when we speak about positive pressure we use bar e.g. 2.3 bar

39
Q

automatic controller

A

device within the steriliser that controls the sterilisation cycle
to ensure it is working - ACT

40
Q

how often should ACT be done?

A

daily: either using the sterilisation cycle parameter values recorded on the printout or electronic data logger, or by manually observing and recording the cycle parameters if there is not a suitable recorder fitted
weekly: manual ACT

41
Q

can the ACT be done when sterilising a standard load?

A

yes
unless also carrying out a steam penetration test for a vacuum steriliser at the same time
- usually 1st cycle of day

42
Q

when must a daily manual ACT be carried out?

A

if a suitable recorder is not fitted

as normally would just be done daily with steriliser recorder - a printer or electronic data logger

43
Q

ACT using a recorder

A

run a sterilisation cycle with a standard load or an empty chamber (the chamber must be empty if also carrying out a steam penetration test in a vacuum steriliser)

at the end of the cycle, check printout/data logger to ensure that the recorded cycle parameters (temp, pressure, hold time) are within the specified range for the cycle and comparable to the values obtained at validation
- keep a record of the values

if ACT unsatisfactory (i.e. recorded temp, pressure or hold time are not within the specified range for the cycle), record the test as a fail and do not use until fault resolved
- return any instruments that were loaded in the steriliser to the start of the decon cycle

sign logbook

44
Q

how often should the Bowie-Dick (steam penetration test) be carried out?

A

daily

45
Q

which type of steriliser needs Bowie-Dick (steam penetration test) ?

A

type B

46
Q

steam penetration test types

A

Bowie and Dick test pack - chemical indicators

Helix/hollow load test

47
Q

Bowie and Dick test pack

A

chemical indicators
test sheet fitted between hundreds of sheets of paper
yellow - dark blue
if air removal part of cycle not performing correctly - yellow spotting on the sheet
pink coloured circle on outside changes colour once processed - purple

48
Q

how to carry out Bowie-Dick (steam penetration test)

A 
place on bottom shelf of load chamber
start cycle
cycle much shorter and doesn't have same drying time
remove pack
open, find test sheet
identify colour change
49
Q

Helix/hollow load test

A

tests for steam penetration by letting us know that the steam was able to contact the chemical indicator by travelling through the entire length of tubing attached to the device

50
Q

is a strip inserted into the pack when processing instruments acceptable?

A

no - not considered to show us anything except a pack of instruments has been through a sterilisation cycle - not a steam penetration test

51
Q

main fct of steam penetration test

A

test steam penetration, also informs temp achieved, adequate air removal
to show steam will rapidly and evenly penetrate a test device that is similar to the intended load

52
Q

where can you get information on recommended steam penetration test device and indicator?

A

MIs

53
Q

carrying out a steam penetration test

A

start of day - select usual cycle and perform test with chamber empty apart from the test device, following test device MIs
record pass/fail in steriliser logbook
if fail - repeat. A 2nd unsatisfactory test result confirms fault
- arrange for a MP (sterilisers) to investigate and don’t use until resolved

54
Q

which steriliser needs an air leakage test?

A

type B

55
Q

how often should the air leakage test be carried out?

A

weekly

56
Q

other names for air leakage test

A

vacuum leak rate
chamber integrity test
vacuum test

57
Q

why is it important air doesn’t leak into the chamber in a type B?

A

if air leaks into chamber at a higher rate than specified by manufacturer, it might interfere with steam penetration into load, and as air will not have passed through the bacteria retentive filter, risk of recontamination of load

air cannot be heated the same way as steam and therefore cannot achieve the required temp, or easily maintain that temp either

58
Q

purpose of the air leakage test

A

verify that:

during negative pressure stage it removes all air within the chamber at the start of the cycle

when reach low pressure set point and vacuum pump stops operating
- machine continues to maintain same pressure and no air is able to enter the chamber from any part of the machine

= verifies that all valves and connections made to the chamber are sealing properly, the vacuum pump is capable of reaching the low set-point that we require and that the door is also sealing onto the chamber correctly

59
Q

carrying out an air leakage test

A

chamber must be cold, dry, empty
close door, machine locks it and cycle starts
machine approaches set point pressure
- then stabilises for 5mins(potential for pressure fluctuations), then measures any differential in the pressure over the following 10mins

  • max permitted change is 13mbar over 10mins or 1.3mbar per min. Max differential <2%

once 10min over - see pressure start to increase as valve opens to allow filtered air back into the chamber

  • happens at beginning and end of cycle - ensure air can’t be drawn in while cycle running (contamination)
  • check machine cycle data - displays all relevant values

record results in steriliser logbook

60
Q

automatic air leakage test

A

if an automatic test is available, do once a week (FMIs), generally with a cold chamber
preferable to have a steriliser that is capable of performing an automatic test as otherwise a test person(decon) is required to perform a weekly manual test
note that some manufacturers specify that an air leakage test is carried out each day before steam penetration test

61
Q

why does the temp remain low in an air leakage test?

A

temp remains low as not a stage that has steam in it

62
Q

how does machine display pressure in an air leakage test?

A
  • pressure absolute displays atmospheric pressure as 1 bar (1000mbar)
  • machine displays it as pressure gauge, showing atmospheric pressure as 0
  • removes air until reaches set point -0.87bar or -870mbar
63
Q

what will any air leakage cause?

A

any air leakage will cause a change in the chamber pressure

64
Q

if user cannot perform an ADFT, what needs to be done?

A

require a TP(D) to visit weekly to do it

- will add significantly to costs so check before purchase

65
Q

which steriliser requires an ADFT?

A

B type

66
Q

freq of an ADFT?

A

weekly

67
Q

what machines are fitted with an air detector?

A

safety device

sterilisers that actively remove air from the load before sterilisation (e.g. using a vacuum pump)

68
Q

what is an air detector?

A

generally a temp probe (/pressure transducer)
in a difficult to reach part of the chamber, potentially at the bottom of a tube attached to the chamber
positioned somewhere that will be difficult to remove air from - the resulting presence of air would mean that the temp at the probe would be lower than that of the temp the chamber probe would be measuring from the steam
- temp differential checked and if it is outwith limits the cycle will fail

69
Q

why is air in the chamber detrimental?

A

doesn’t maintain temp the same way that steam does, and is also much harder to heat
if air present during cycle could mean not every part of chamber and load being processed will reach required temp for required time - could allow MOs to survive

70
Q

how much air is allowed to enter in ADFT?

A

small measured bleed of air is allowed to enter the chamber
recommended rate 11mBar/min - v small - approx 0.5% of the pressure that we are working with
- even v small amount of air has potential to affect cycle set points

71
Q

after an ADFT

A

retrieve data from machine

record in steriliser logbook

72
Q

which cycle can be used for the ACT?

A

1st production cycle

73
Q

B type ACT things to record

A

date, time, cycle number, operator
more data - cycle more complex
record info for: vacuum stage at start, steam introduction and sterilisation stage and post-vacuum/drying stage. Time for each stage

record readings at each peak, low pressure and high pressure
- pulsing: record low pressure, high pressure and temp
+ pulsing: record low pressure, high pressure and temp
sterilisation temp and pressures - at start of stage and then at 1min intervals until it finishes

74
Q

N type ACT things to record

A

date, time, cycle number, operator
record e.g. cycle times and sterilisation temps, times for diff stages
record temp and pressure (if it is displayed) of the sterilisation stage at 1min intervals
after create own ACT record can retrieve the machine cycle data as well and check both records against each other

75
Q

vacuum steriliser - quarterly

A 
weekly safety checks
Bowie Dick test
air leakage test
ADFT
calibration of test instruments
ACTs and verification of calibration
small load thermometric test
calibration checks (post-testing)
produce cycle graphs to make sure all cycle set points are being achieved
76
Q

sterilisers - what must be done annually?

A

annual validation

decon (5 decks)

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