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34 Cards in this Set
- Front
- Back
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decontamination |
- removal of micoorganisms and unwanted matter from contaminated materials or living tissue
- required in order for object to be disinfected or sterilised |
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disinfection
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-inactivation of non-sporing micro-organisms through thermal or chemical means
- reduces numbers of micro-organisms to a level that is not harmful but may not necessarily kill all |
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sterilisation
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-complete destruction of all micro-organisms including spores eg autoclave
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power supply
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- white powerpoints are mains power
- red powerpoints are essential power, backed up by hospital generators. If mains power fails detected by sensor which will trigger a transfer switch and activate the internal emergency generator - blue powerpoints are uninteruptable power supply - incoming mains converted to DC power which powers 12V battery, output from battery is then converted back to AC power. Provides finite power source. Keep all mission critical equipment attached to this eg anaesthetic machine, CPB |
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power failure protocol
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OR complex:
- warden with 2 way radios - published emergency procedures manual with protocol available anaesthetic - call for help - dont start elective surgery - finish current surgery ASAP - assess ABCDE, ensure still ventilated by machine - aim to convert to SV GA, possibly need to change to TIVA - determine battery life of anaesthetic machine - back up drugs if pixus machine - rationalise equipment attached to UPS power supply |
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universal precautions
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- infection control techniques to decrease transmission of pathogens via blood and other bodily fluids.
- applied to every patient - aim is to protect patient and staff - standard precautions includes universal precautions but also protects against droplet, airborne and contact - additional precautions if TB, prion disease |
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gas safety
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- level 1 check by bioengineers to ensure adequate supply pressures, gases not crosses, isolation valve, correct composition and check of oxygen failure alarms
- sleeve index system from wall with colour coded hoses eg white O2 - cylinder O2 supply with pin index system - level 2 check at start of each list to ensure that O2 cylinder available and full, piped gas at appropriate pressure, multi gas analyser - gas supply pressures on front of machine - oxygen supply failure alarm with audible signal once O2 driving pressure falls below certain level - emergency O2 flush -mechanical O2 know must be fluted and larger than others for tactile identification - O2 must be last gas added to common gas manifold - if can also deliver N2O must have interlock to ensure dont deliver hypoxic mixture - fresh gas outlet must have 22/15mm connector - vapouriser interlock so only one can be on at a time - scavenging system - alarm for high and low pressures and disconnect - check for circuit leaks and presence of one-way valves - must be 2 facility to deliver O2 and ventilation should primary source fail - monitoring of O2, CO2, volatile, disconnection alarm, pulse oximetry - back up battery of 30mins duration - mains failure alarm |
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plenum vaporiser
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- vapouriser is device that delivers clinically useful concentrations of volatile anaesthetic agent
- FGF enters vapouriser inlet, split into bypass and carrier gas. Carrier gas is diverted into chamber with volatile - amount of gas diverted depends on desired concentration of volatile and |
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safety features of plenum vaporiser
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1/ temperature compensation eg bimetallic strip adjusts for cooling that occurs due to latent heat of vaporisation
2/ temperature stabilisation eg copper has high specific heat capacity that is able to absorb heat loss that occurs with vaporisation 3/ flow compensation via use of wicks to maximise surface area to ensure bypass gas is fully saturated when leaves volatile chamber even at high flows 4/ agent specific interlock to prevent inadvertent incorrect filling 5/ vaporiser interlock which allows only one vaporiser to be on at once 6/ filling point location located to minimise risk of overfilling 7/ anti-tilt mechanism by locking vaporiser onto back bar 8/ ET agent monitoring 9/ anti-pumping effect avoided through use of 1way valves and long and convoluted input tubing. Prevents backflow of volatile into bypass stream 10/ anti-pressure effect to avoid pressure changes occuring in vaporiser affecting the SVP. Occurs via 1-way valves 11/ locking spindle with o rings and pressure sensors to detect leak from back bar |
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O2 storage
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-mainly stored via VIE (vacuum insulated evaporator)
- stored in liquid form below critical temp of -118 at 1000kPa - insulated to prevent inadvertent heating (could lead to explosion) or heat loss from latent heat of vaporisation - sits on scale to indicate when needs refilling based on weight |
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O2 storage safety features
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- pressure relief valve at 1500kPa (if low O2 use or warm temp)
- prssure raising valve to allow environmental heat to cause vaporisation if high O2 use or low environmental temperature - small bank up VIE in case of failure - backup bank of O2 cylinders in case of failure (enough O2 for 2/7, stored in dry cool area with pin index system) |
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O2 delivery to OR
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- all gases pass through heat exchanger to warm them
- pressure down regulated from 1000kPa to 400kPa in pipeline - wall outlet has sleeve index system with colour coded hoses - isolation vales to cut off O2 supply to theatre - low pressure alarms - O2 pipeline, gas analysis, absence of incorrect crossing over of gases checked by bioengineers as part of level 1 check |
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macroshock
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- describes current flow >1mA, and able to be sensed by patient
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RCD
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- 3 wires: 1 active, 1 neutral and 1 earth
- if the current between active and neutral wires is not equal, creates magnetic field which induces current in 3rd wire which trips the RCD "circuit breaker" - can detect as little as 30mA (wont protect against microshock) but does protect against macroshock |
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Floating transformers and LIM
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- large transformers in wall cavity which are seperate from mains power circuit
- induced current of 240V between 2 active wires - as circuit is distinct from grounded earth, no current will flow if person touches wire - LIM intermittently checks difference between isolated circuit and earth and alarms if >5mA as indicates loss of floating supply. Indicates how much current could flow if there was a 2nd fault - protects against macroshock |
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insulation
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- primary prevention: seperates all live material via insulation of all mains powered equipment. Can potentially deliver shock if one fault
- secondary prevention: all medical equipment must have double protection class 1: all exposed electrical parts are earth connected via earth conductor class 2: primary insulation supplemented by 2nd layer ie double insulated class 3: power supplied at extra low volatage 24V |
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electrical areas for patient equipment
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- classified according to the maximum allowable current leakage
- type B: class 1, 2 o 3 insulation with max allowable current leakage of 100mcgA - type BF same as B but on floating circuit (ie with LIM) - type CF same as BF but max allowable current leak is 10mcgA occurs due to equipotential earthing |
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microshock
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refers to current that is below the sensory threshold (100mcgA-1mA) that is still able to induce VF if passes through the myocardium eg via CVC, PPM leads
- VF threshold is 60-100mcgA |
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methods to prevent microshock
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- australian electrical standards and frequent checks of equipment
- electrical areas that designated depending on max allowable current leakage B - insulation class 1-3, max leak is 100mcgA BF - same as B but on floating circuit CF- cardiac protected, max leakage current is 10mcgA. All electrical equipment is equipotentially earthed - patient not earthed - intact dry skin |
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soda lime
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- used to absorb CO2 from circle anaesthesia system
- contains Ca(OH)2, NaOH, water, indicator (ethyl violet) - H2O + CO2 -> H2CO3 H2CO3 + 2NaOH -> Na2CO3 + 2H2O + heat Na2CO3 + Ca(OH)2 -> CaCO3 + 2NaOH + heat - mesh sized to maximise SA but limit resistance to flow |
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hazards associated with soda lime
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- CO production: occurs with dry and hot dessicated soda lime exposed to low flows, high volatile concentration, desflurane worst
- compound A: occurs with sevoflurane. Dose dependednt nephrotoxin in rats, however unable to generate significant concentrations in humans. Risk factors, low flow, high temp high sevo conc - fires and burns and explosions - circuit leak - depot for volatile agent eg MH - skin iriitation - hypercarbia if not replaced |
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T piece
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- mapleson circuit D, E and F (bain co-axial, ayre's t piece and jackson rees modification respectivey)
- advantages light weight poratable low resistance low dead space fast wash in and out good feel of bag, easy to deliver PEEP/CPAP easily Disadvantages: - ineffeicient - need high FGF to prevent rebreathing (2-3x MV) - increased use of volatile = expensive - pollution (no scaveinging) - low humidity - complexity |
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Circle system component location
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-FGF after soda lime to prevent dilution of recirculating gas and also absorption of volatile by soda lime slowing induction with volatile. Also will dry out soda lime. Needs to be on machine side of inspiratory valve as otherwise would bypass patient on expiration
- unidirectional valves close to patient as possible to prevent backflow and rebreathing -HME should be close to patient as possible to minimise heat loss and also protects circuit - overflow valve immediately before the absorber to minimise venting of gas - CO2 absorber located between APL and FGF to conserve absorbent by minimising passage of exhaled gas - gas sampling ports sidestream to decrease resistance - vapourisers outside circle to limit concentration surges |
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Ideal disconnect alarm
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- ability to accurately detect disconnection of circuit between circuit and patient
- pressure sensing alarm with sensor on inspiratory arm near patient - timer with audible alarm, alarm if excessive high, low or sustained pressure - cheao -rapid response - temporary disable function - safe with no infection risk, electrocution risk, interference with diathermy - ability to detect false negatives eg blocked HME filter, high inspiratory flow rates |
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O2 delivery devices
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- concentration delivered depends on MV of patient and flow.
- if MV is in excess of flow, will entrain RA and dilute FiO2 - can be divided into low flow/variable devices eg hudson mask, non-rebreather and nasal prongs and high flow eg venturi mask |
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Level 1 check
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- detailed check performed by trained service personnel eg biomedical engineer
- performed with new systems, post repair or when due for service |
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level 2 check
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- performed at the start of each list
- responsibility of anaesthetist but can be delegate to suitably qualified personnel eg nurse - check service label - check sleeve index system of wall O2 supply - check presence of O2 cylinder and ability to turn on and off (pin index system) - check gas supply pressures (4 bar for wall, 137 bar for cylinder) - correct functioning of oxygen failure alarm with wall O2 disconnected and cylinder shut and cessation of alarm when cylinder turned on - check correct functioning of anti-hypoxic delivery system via interlock between N2O and O2 - check vaporiser full - perform low pressure leak test via use of pressure bulb attached to CGO with flows off and vaporiser on, must stay inflated for 10secs - check circuit via sustaining pressures of 30cmH20 with flows of 300mls/min, correct functioning of unidirectional valves via use of ventilator - confirm soda lime not exhausted - scavenging on - suction available - airway equipment: 2 working laryngoscopes, LMA and airway adjuvants - pump delivery devices available - presence of alternate O2 delivery eg self-inflating bag |
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level 3 check
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- performed prior to commencement of anaesthesia for each patient
- check vaporiser level - recheck circuit if changed - check airway and pump delivery devices available as per level 2 check |
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O2 flush valve
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delivers100% O2 at 35-75L/min
- provides link between high pressure and |
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Tec 6 vaporiser
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- designed because SVP so high that BP is ~23 degrees
- Tec 6 designed to try and solve problems with inconsistent delivery - heated and pressurised - designed as dual-gas blender. 1 provides FGF, other serves as a reservoir of desflurane vapour. Amount of vapour is added to FGF depending on dialed concentration - linkage between 2 systems via pressure transducers and electronics |
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aladdin cassette vaporiser
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- allows for delivery of multiple different volatiles when connected to machine
- recognised by machine via magnet. Also colour coded - has inboard CPU which receives multiple inputs on concentration control dial, pressure sensor, temperature sensor, flow measurement uit |
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scavenging
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- process of collection and removal of waste gases from OR to limit pollution
- minimum safe level exposure polices |
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reasons for pollution
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1/ anaesthetic
- leaving gas on at end of procedure - poorly fitting face mask - refilling of vaporiser - flushing the circuit - use of uncuffed ETT - use of breathing circuits that are hard to scavenge 2/ equipment failure |
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how gas scavenged
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- collected from either APL valve or ventilator relief valve
- transferred via specific tubing (different size to circuit to prevent inadvertent connection) -scavenging interface may be open or closed system. must have positive and negative relief valves (open just open to atmosphere) with large reservoir - vacuum applied to interface, must be greater than MV - tubing to connect to gas assembly - gas assembly either active or passive expulsion of gas |
