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108 Cards in this Set
- Front
- Back
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Define sterilization:
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complete destruction or elimination of bacteria, spores, viruses, and fungi by physical or chemical methods
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Define antisepsis:
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inhibition of growth and development of microorganisms without necessarily killing them
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What is the effect of water harness on sterilization?
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Increased water hardness reduces removal of blood; induces or facilitates surface pitting
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How do ultrasonic cleaners work?
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High frequency vibratory waves create cavitation followed by a mini vacuum
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What is cavitation?
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Formation of liquid cavities or enlarged gas bubble as a result of negative pressures
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What creates the mini vacuum phase of ultrasonic cleaning?
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When positive pressure is applied the enlarged gas cavitations implode, creating a shock wave
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What are the benefits of ultrasonic cleaning?
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Dislodges debris from holes, jaws, joints, channels and complex surfaces; disrupts air pockets; ensures wetting during the entire cleaning process
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What is the cleaning time and frequency for ultrasonic cleaning?
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3 minutes, 35 kHz
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Storage times for single wrapped 2 layer muslin on an open shelf and closed cabinet?
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2 days on open shelf, 7 days in closed cabinet
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Storage times for double wrapped 2 layer muslin on an open shelf and closed cabinet?
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3 weeks on open shelf, 7 weeks in closed cabinet
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Storage time for single wrapped crepe paper on an open shelf and closed cabinet?
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3 weeks on open shelf, 8 weeks in closed cabinet
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How many times can treated pima cotton be used?
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75
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What are the benefits of sterilization fleece?
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More durable, better handling, longer storage times
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Types of sterilization indicators:
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chemical, biologic
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Difference between chemical and biologic indicators:
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chemical indicators determine that packs have been exposed to sterilization temperatures, biologic indicators provides more information that sterility has been achieved
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Examples of biologic sterilization indicators:
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bacillus stearothermophilus for steam, formaldehyde, or hydrogen peroxide sterilization; bacillus subtilis for ethylene oxide and dry heat sterilization; bacillus pumilus for radiation sterilization
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Examples of physical sterilization:
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thermal energy, filtration, radiation
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How does dry heat thermal sterilization work?
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Oxidation, removal of water
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How does moist heat thermal sterilization work?
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Coagulation and denaturation of proteins
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What is the advantage of moist heat sterilization vs dry heat sterilization?
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Moist heat kills at lower temperatures and exposure times
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Examples of steam (moist heat) sterilizers (autoclaves):
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gravity displacement, prevacuum, pulsed steam pressure
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Function of gravity displaced autoclave:
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steam introduced under pressure at top of unit, air pushed to bottom then out of unit via a thermostatic valve
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Function of prevacuum autoclave:
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air is evacuated by a vacuum pump before steam is introduced
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Function of steam pulsed autoclave:
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steam pulse increases pressure in unit to a set pressure then vented to a set minimum pressure prior to the next pressure pulse
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What is the difference between gravity displacement and prevacuum autoclaves?
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Steam penetrates the unit nearly instantly so decreases the sterilization time
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What is the difference between prevacuum and steam pulsed autoclaves?
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The removal of air depends on the amplitude and strength of each pulse, faster than gravity displaced but slower than prevacuum but less expensive than prevacuum
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What are the present European standards for steam sterilization to include prion sterilization?
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134C for 18 minutes
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What is the heat-up time for prevacuum and steam pulse autoclaves?
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1 min
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What is the temperature for heat-up in prevacuum and steam pulse autoclaves?
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120C
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What is the minimum standard for time and temperature for gravity displaced autoclaves?
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13 minutes, 120C
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What is the minimum standard for time and temperature for any steam autoclave?
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121C for 15 minutes and 15 psi (2 atmospheres)
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What is flash sterilization?
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Emergency sterilization (fast) of instruments and material
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What type of steam autoclave can flashing be performed in?
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only prevacuum
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What are the flashing conditions for prevacuum autoclaves?
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3 minutes, 131C
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What is the exposure time and temperature for large linen packs in a gravity displaced autoclave?
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30 minutes, 120C
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What is the exposure time and temperature for large linen packs in a prevacuum autoclave?
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4 minutes, 131C
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What is the drying period after steam sterilization?
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20 min
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What is filtration sterilization used for?
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Air supply to surgery rooms, industrial medication preparation, preparation of small volumes of fluids
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What are the 2 types of filtration filters?
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Screen, depth
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Define screen filter:
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function as a sieve to remove organisms and particulates larger than filter pore diameter
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Define depth filter:
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trap organisms and particulates by absorption and mechanical entrapment
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Examples of chemical sterilization:
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ethylene oxide, gas plasma
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What are the limits of ethylene oxide sterilization?
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Large equipment size, longer time requirements, toxicity of agent
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What are the indications of ethylene oxide sterilization?
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Items not able to be sterilized by steam such as laparoscopes, light cables, camera heads
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MOA of ethylene oxide:
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alkylation inactivation of protein, DNA, RNA
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Spectrum of ethylene oxide:
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bacteria, fungi, viruses, spores
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What carrier agents are used with ethylene oxide?
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CO2 (most common), Freon
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What concentrations of ethylene oxide are used?
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450-1500 mg/L
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Benefit of increased concentration of ethylene oxide:
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doubling concentration approximately halves sterilization time
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What temperature range is used for ethylene oxide sterilization?
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21-60C
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What is the benefit of increasing ethylene oxide sterilization temperature?
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Activity is about doubles with each 10 C increase
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What is the exposure time range for ethylene oxide sterilization?
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48 minutes to several hours
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What humidity should ethylene oxide sterilization be performed at?
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33-60%
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what is the storage time for ethylene oxide sterilized packs?
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90-100 days for plastic wraps sealed with tape or a year for wraps heat sealed
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What are the advantages of gas plasma sterilization?
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Short turnaround time, no health hazards, low temperature operation
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MOA gas plasma sterilization:
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H2O2 converted to gas plasma by radiowaves, microbial killing via free radicles
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What cannot be sterilized with gas plasma?
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Flexible endoscopes, liquids, items of plant fiber origin, items with long lumen or closed lumen, folded plastic bags or sheeting
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What is the difference between a disinfectant and an antiseptic?
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Disinfectants are used on inanimate objects and antiseptics are used on living tissue
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Define high level disinfection:
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use of chemical sterilant for times that are insufficient to achieve sterilization but sufficient to inactivate all organisms but not spores
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Examples of disinfectants:
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aldehydes, peracetic acid, H2O2, electrolyzed acid water, chlorine dioxide, 2-butane peroxide, peroxygenic acid
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Examples of aldehydes:
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gluteraldehyde, ortho-phthalaldehyde, succindialdehyde
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MOA gluteraldehyde:
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alkylation of sulfhydryl, hydroxyl, carboxyl, and AA bonds to alter DNA, RNA, protein synthesis
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Indications for gluteraldehyde disinfection:
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endoscopes
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Contraindications for gluteraldehyde disinfection:
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hinged, corroded, or deep crevice instruments
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Trade names of gluteraldehyde:
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Cidex, Omnicide, Abcocide
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Disadvantages of gluteraldehyde:
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toxicity from exposure to staff in preparation, patients if instruments not rinsed properly
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MOA peracetic acid:
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denaturation of proteins, disruption of cell wall, oxidation of sulfhydryl and sulfer bonds
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What is the concentration and contact time for peracetic acid sterilization?
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0.09%, 10-15 minutes contact time
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What are the advantages of peracetic acid vs gluteraldehyde?
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Similar or better biocidal effect, less irritating to staff, safer for environment, does not create a biofilm, can remove gluteraldehyde-hardened material from instruments
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What are the disadvantages of peracetic acid?
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Less stable than gluteraldehyde, strong odor, can be corrosive, efficacy is linked to pH, expensive, weak carcingogen
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MOA H2O2:
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hydroxyl radicle formation disrupt membranes, proteins, DNA, RNA
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What is the minimum effective concentration of H2O2?
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6%
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Types of electrolyzed acid water:
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strong (pH <3), weak (pH 6-7)
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MOA of electrolyzed acid water:
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generation of hydroxyl radicles disrupts cell membranes, proteins, DNA, RNA
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Examples of antiseptics:
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alcohols, chlorhexadine, iodine/ iodophors, hydroalcoholic solutions, octenidine, phenols, quaternany ammoniums
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Examples of alcohols:
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isopropyl(propanol), propan-2-ol & propa-1-ol (sterillium), ethanol 96% & biphenyl-2-ol (desderman pure)
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MOA alcohols:
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protein denaturation
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Spectrum of alcohols:
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bacteria
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Disadvantage of alcohols:
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inactivated by organic debris, no residual activity
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Effects of alcohols on povidone-iodine:
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increases the release of free iodine
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Formulations of chlorhexadine:
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2% chlorhexadine diacetate, 4% chlorhexadine gluconate
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Spectrum of chlorhexadine:
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bacteria, variable efficacy against fungi & viruses
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MOA chlorhexadine:
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disrupts cell membrane, precipitates cellular proteins
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MOA of iodine/ iodophores:
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penetrates cell wall and inhibits protein synthesis by forming complexes
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What is the active agent in iodine?
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Either molecular iodine (I2) or hypoiodic acid (HOI)
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How much free iodine in a 10% providone-iodine solution?
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1%
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What is the recommended level of free iodine for antimicrobial activity?
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1-2mg/mL
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How can release of free iodine be enhanced?
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Dilution
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Disadvantages of iodine/iodophors?
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Need to be in contact with skin for 2 minutes to release enough free iodine to kill bacteria, can be inactivated by organic debris
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Spectrum of iodine/iodophores:
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bacteria, fungi, viruses
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Examples of phenols:
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phenol, cresol, hexachlorophene
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Advantages/ disadvantages of phenols:
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good residual activity & not affected by organic material but slow onset of activity & inactivated by alcohol
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Example of quaternary ammonium:
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benzalkonium chloride
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MOA quaternary ammonium:
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cationic surfactant dissolves lipids in bacterial cell wall & membranes
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Disadvantages of quaternary ammonium:
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only affective against bacteria, forms a residual layer, and is inactivated by organic debris
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Types of reuseable woven fabrics:
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cotton muslin, pima cotton
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Threads per inch cotton muslin:
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140
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Threads per inch pima cotton:
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270
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Disadvantages of cotton muslin:
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allows passage of bacteria when wet, large pore size allows (50-100 um) allows passage of bacteria even when dry
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Disadvantages of pima cotton:
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strikethrough when wet
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What can prevent strikethrough in pima cotton?
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Treatment with quarpel make it water resistant
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Advantages of disposable drapes:
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low particle counts in surgery room, decrease # of bacteria isolated from surgical wound by 90% (vs cotton), decrease wound infection rates by 2.5% (vs cotton)
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Number of air particles and bacteria per cubic foot of air:
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250,000 particles (bacteria, lint, skin cells) and 11 to 13 bacteria
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Difference between gortex fabrics and treated pima cotton:
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more durable, retain barrier for up to 100 washings (vs 75 for pima)
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Accepted standard for surgical gloves:
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1.5% contain punctures before use (reports say that 2.7-4.1% contain punctures)
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Post-surgical glove perforation rate:
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31% of gloves have perforations; if double gloved then 16-67% of outer glove have perforations and 8-30% of outer gloves have perforation
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Where are perforations in gloves most common?
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Thumb and index finger of non-dominant hand
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What is the objective of surgical hand scrub?
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Remove gross dirt and oil, decrease bacterial counts, prolonged depressant effect on transient and resident microflora
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