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113 Cards in this Set
- Front
- Back
def
humidity |
water in a gas vapor
molecular water in gas |
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def absolute/ actual humidity
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actual amt of water content of gas fully saturated
**(44mg/L)** |
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def
partial pressure |
pressure exerted by water vapor, temp increases, velocity of gas molecule increases,as moleclues hit objects in their path their force increases. The force is measured as partial pressure
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partial pressure at body temp of 37 degrees celcius
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47 torr or mmHg
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def relative humidity
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ratio of content (AH)/capacity (PH) or
content/potiential_RH |
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relative humidity capacity
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when gas contains all the H2Oit can it is saturated. temp increases, capacity increases
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humidity deficity
(deficit is eliminated by our resp passsages warming and humidifying) |
dif bewtwnn body humidity and watercontent of RA gas
BH-AH= humidity deficit |
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body humidity is ____torr?
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47 or 44mg/L
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def
condensation |
when cooling occures h2o changes from vapor to liquid. paricles can be reborn
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def
dew point |
temp at which h20 vapor condenses to liquid
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def
evaporation |
h20 moving from liquid to gas
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def
coalescence |
particles grow by absorption
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def
rain out |
particles leave suspension settling occurs due to gravity (cold room warm humidifying tube)
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def
penetration |
the max depth to which particles can be carried (down to alveoli)
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def
deposition |
instability of aerosol which permits rain out (deposition up high)
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def
retention |
the depositon of particles at a specific location within the resp tract
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def stability
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the ability of aerosol to remain in suspension over a period of time
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what is stability effected by
(aerosol stability) |
size and nature of aerosol particulate,
concentration of particles present,ambient humidity,mobility of carrier gas |
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water vapor content and pressure
room temp 77 F 25 C |
partial pressure 23.69 torr
capacity 23.04 mg/L |
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water vapor content and pressure
body temp 98.6 F 37 C |
partial pressure
47 torr capacity 43.8 mg/l |
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4 goals of humidity therapy
it doesn't directly add water to the airways but to the gas instead |
provide humidity level in room air, supply enough h20 to inspired gas for pt comfort, heating gas to provide 100% RH at body temp,
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4 indications for humidity therapy?
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retained secretions
mucus plugging bronchospasm caused from dry air, irritation to airway |
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3 functions of the nose?
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heat, humidify and filter inspired air
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how much h20 may the nose add to the air a day?
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1000 ml a day
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what percentage of RH is at the nasopharynx?
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75%-80%
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how does the nose warm
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copius capillary blood flow allows for transfer of heat to inspired air
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how does the nose filter?
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a combo of lrg hair follicles and mucus layer atop the mucosa
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inadequate humidification leads to???
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imparmenyt of ciliary activity,mucus movement,inflammatory change, necrosis of pulmonary epithelium, retention of thick secretions,mucosal incrustation, bacterial infiltration of mucus, atelectasis and pneumonia
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3 catagories of humidifiers?
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simple
heated and hygroscopic condenser (HME heat moisture exchange) |
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3 ways humidity is quantified?
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actual/absolute
partial pressure relative humidity |
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how does the simple humidifier work?
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pass over: gas flow passes over a reservoir of water. H20 simply evaporates into the gas increasing humidity
disadvantage:low efficiency because the time of exposure is too short |
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how does the bubble humidifier work?
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gas flows thru hollow tube to a diffuser which breaks gas into sm bubbles. as they float to the surface the h20 evaporates onto them.
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what kind of pt uses a bubble humidifier
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a pt with intact upper airways who need supplemental humidity (intact means no holes)
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what is import to remember about the bubble humidifier
fyi capable of 35% RH |
keep h20 level as high as possible.
LOWER H20 LEVEL OR FASTER FLOW =lower RH |
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how does a underwater jet humidifier work
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mixes both bubble and jet principle. produces an aerosol as bubbles float to the top they pick up more humidity. adv: less dependent on H20 level dis: produce particles there is a greater risk of contamination
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3 factors that influence humidifier efficiency
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temp, contact time and surface area
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3 types of simple humidifiers
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bubble and jet humidifier & underwater jet humidifier
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how does a jet humidifier work
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produces and aerosol but the baffles remove lrg particles. incrases both time and surface area contact
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how do heated humidifiers work?
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body humidity levels are needed heat must be applied. tubing may be heateddecreased temp from humidifier and mini
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tubing may be heated, heat wire circuits allow ???
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decreased temp from humidifier and minimizes condensation
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what kind of pt can a wick humidifier be used on?
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at 100% RH at body temp can be used on intubated pt
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how does a wick humidifier work?
90% can be achieved |
uses hygroscopic wick (sponge or paper) that absorbs h20 by capillary action. gas passes thru or next to the wick for evaporation. addition of heat increase levels of humidity
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capablility and limitation of wick humidifier?
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adv:saturation can be maintained even at continuous high flows creating greater efficiency
less resistance to flow demand from the pt. (decreased WOB) |
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def
aerosol |
particles suspended in gas
can be solid but is usuall liquid |
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Def
gravity |
particle size increase the mass size increases and gravity will have a greater pull taking it out of suspension
fyi(As the particle size doubles the force gravity has increases 4 fold) |
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factors influencing depositon in airways??
GRIT PP |
gravity
random motion-kineticactivity inertia temp physical nature pt ventilatory pattern |
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def
kinetic activity |
molecules of gas are in constant and random motion. they travel in straight lines until they collide with something else. at that point they rebound off and resume straight path
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fyi increase mass=increase inertial impaction
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fyi: increase temp=kinetic energy increases
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def
inertia in reference to aerosols |
tendency to travel in a straight line in spite of a change in direction of the carrier flow gas
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temp in reference to aerosols
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as temp of a carrier gas increases (humidity held constant) the aerosol particles will evaporate into the carrier gas. if an aerosol is introduce into a humidified carrier gas the particles will grow together
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aerosol jtf:hydroscopic particle has tendency to absorb water which will increase size and mass (early rain out)
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solutes in h20 jtf:hypertonic particle will gain water
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solutes in h20 jtf:hypotonic will lose water
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solutes in h20 jtf: electrical charge has little effect on solutes in solutions
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what kind of ventilatory pattern will increase aerosol penetration into the lung
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slow deep breath followed by a pause (3-5sec)before exhalation
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3 goals of aerosol therapy
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improve bronchial hygiene
humidify delivered gases deliver medications |
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to improve bronchial hygiene what do you use to mobilize secretions
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use bland solution(h20,NaCl or sodium bicarb)
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diagnose bronchial hygiene need
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sputum induciton specimen for gram stain,C&S to determine pathogen or cytology to determin cell type for malignancy
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advantage of aerosol therapy delivery?
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aerosol route always available, direct deposition to target site. smaller dosage,faster onsite ,decreased systemic side effects
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disadvantage of aerosol therapy delivery?
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dosage of drug is difficult to estimate
pt compliance required |
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aerosol therpy particle size measured in ?
size determines? |
microns
depth of penetration and stability |
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aerosol therapy jtf: smaleer the particle size the greater the depth of penetration
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aerosol therapy jtf:particles larger than 10 microns are deposited in the upper airway by nasal filtration
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aerosol therapy particle output volume is measured in
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ml/min or ml/hr or cc/min or cc/hr
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factors that control aerosol therapy particle output ???
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particles size rance
lrg increase vol but decrease penetration, small particles decrease vol but increase penetration (density # of particles) sm particle may lead to derease vol output |
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4 hazards of aerosol therapy
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cause bronchospasm
increase airway obstruction systemic fluid overload (in infants) cross contamination |
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how can aerosol therapy cause airway obstruction?
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hydrophilic(water loving)secretions swell when they absorb water and result in lower airway obstruciton
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how can aerosol therapy cause bronchospasm?
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aerosol droplets are foreigh bodies can precipitate bronchospasm
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4 aerosol delivery devices
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aerosol masks, face tent, t piece, briggs adaptor and trach mask or collare
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aerosol delivery device
aerosol mask |
like simple o2 mask with lrg bore tubing 22mm outside diameter,2 outlet ports are bigger to facilitate exhalation,low flow,to keep air entrainment to a minimum increase flow
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aerosol delivery device
Face tent |
sheild designed to be strapped under the chin enclosing lower part of the pt face. front edge should be higher than level of nares. same large bore inlet connection. same lrg bore inlet connection
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aerosol delivery device
t-piece/briggs adaptor |
aerosol is always used when the pt upper airway is bypassed, provides 02 and aerosol,15 mm ID, fits over ET tube or trach tube, other 2 openings have 22 mm outside diameters for lrg bore tubes, a reservoir tube is often added to insure fio2 when pt draws in a breath
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aerosol delivery device
trach mask or collar |
fit over trach tube or stoma
provides 02 and aerosol 22 mm outside diameter inlet form lrg bore tubing adv:pt can be suctioned W/O removing device thus no interruption of fio2 dis: can't guarantee fio2-low flow sys w/o reservior |
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the purpose of aerosol generator nebulizer (3)
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repiratory tract humidification, mobilization of secretions,delivery of meds
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2 ways nebulizers are catagorized
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pneumatic-gas powered
electrically-powered with electric current |
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how does the aerosol generator nebulizer work
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uses venturi & bernouilli principal. uses gas source, capillary tubes and baffles
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what is a baffle??
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any object placed in the path of aerosol particles.
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why use a baffle on a neb?
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reduces the ave size of aerosol particles by removing larger ones
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5 types of gas powered nebs
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lrg vol jet neb
hydronamic (babbington) sm vol jet neb MDI-metered dose inhaler SPAG-small particle aerosol generator |
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LRG volume neb
pneumatic (gas powered) |
mainstream neb
jet principal to entrain fluid (bernoulli), lrg volumes 250-3000 ml particle size 2-20 microns output 0.3-7 cc/min RH 60-70% FIO2 .3-1.0 |
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on a lrg volume neb what kind of 3 aerosol devices are used?
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face mask, face tent, t piece or trach collar
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when using a lrg neb what happens if you don't insure the pts constant o2 and the total inpiratory flow is decreased not kept between 25-30 lpm????
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fio2 is decreased
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neb entrainment ratios
100% |
0:1
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neb entrainment ratios
60% |
1:1
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neb entrainment ratios
40% |
3:1
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neb entrainment ratios
35% |
5:1
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neb entrainment ratios
30% |
8:1
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what happens if the flow from the neb unit is inadequate?
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density AND fio2 drop due to increased air entrainment by the pt
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jtf neb:output of the lrg neb increases because larger particles are carried. density decreases as a relust of relatively greater increase in gas flow.
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jtf neb:if the total flow from the unit does not meet the pt inspiratory flow demands the aerosol denisty and fio2 will drop
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air dilution increases aerosol but.....
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aerosol density decreases (decreasing RH)
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heated nebulizer
75-95%RH at body temp |
adv increase temp=increase capacity and RH.
temp depends on the liquid level,total gas flow, tube length and room temp |
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4 possible heated neb precaustions
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monitor temp at pt connector
burns are hazards greater risk of bacterial contamination and condensation in tubing increases fio2 and decreases total gas flow to the pt. |
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4 types of neb heaters
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immersion heater (rod in h20)
heating plate attchs to metal plate on neb (has thermostat), capillary heating sys,flex wrap or wrap around (no shut off) |
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hydrodynamic babinton, hydrosphere, solosphere nebulizer
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different from rest because of jet construction
particles size 1-10 microns mmd is 3-5 microns consistent aerosol density over wide flow range. output vol 1-2 ml/min (affected by thickness of fl over sphere,size of outlet on shpere and the amt of air entrained) operating temp 6-10 degress below ambient. no heat avail |
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3 types of electric ultrasonic large volume nebs
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DeVibiss
Monaghan Mistogen |
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goal of the electric ultrasonic large volume nebs
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to produce a very dense mist with a water content greater than 100mg/L
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output of the electric ultrasonic large volume nebs and particle size
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3-6ml/min (depending of model)
90% withnin .5-3 micron range |
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indications of the electric ultrasonic large volume nebs
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aid in the mobilzation of secretions and med delivery
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how does the ultrasonic neb work??
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conversts electrically enery into sound energy which creates aerosol particles.
based on the piezoelectric quality(of piezoelectric crystal)where a current is sent thru it. Frequenty determines particle size. amplitude determines output & is manually controlled. increase output by increasing amplitude |
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4 hazards of untrasonic nebs
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overhydration of secretions
electrical hazard contamination(potential vehicle for spread of infection) continous wetting the lunwith with ns has resluted in bronchopneumonia like pulmonary changes |
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why use an untrasonic neb?
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intermittent use
use to induce sputum home use to replace steam vaporizer aerosol medication delivery |
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(SPAG)small particle aerosol generator specially designed for ???
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delivery of anti viral agents (ribavirin, virazole) for infants with RSV bronchiolitis
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SPAG small particle aerosol
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5% of suspended particles are below the 5 micron range
6hr treatment time aerosol drug enters a drying chamber where anhydrous gas causes further shrinking & evaporation of particles adminstered w/ oxyhood of other open system |
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sm vol neb advantages
(hand held) |
aerosol route is alway avail
direct to target site minimum dosage therefore decreased side effects |
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sm vol neb disadvantages
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non compliant
hard to know dosage uner or over utilization minimal systemic side effects:muscle tremor oropharyngeal stimulation leasds to gag reflex tracheobronchial irritation leads to bronchospasm nosocomial infection therapists are exposed aerosol drugs |
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sm vol neb aerosol delivery method
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add right angle to neb outlet as another baffle
flex tube can be added to increase the time particles flow in the circuit before reaching pt flex tube can be added on the inlet to serve as a reservoir for exhaled sm particlees (lrg ones rainout) |
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types of sm vol nebs
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mainstream
sidestream slip stream |
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mainstream sm vol neb
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main gas flow to the pt flows thru the aerosol as it is produced,
less evaporation occurs particles size is larger increase the flow and increase the total output useful for delivering greater volume of drugs(ie mucolytics or local anesthetic to lrgr airways) |
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sidestream sm vol neb
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aerosol drips or is injected into main gas flow
produces sm particles more particles rain out so output is less |
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slip stream NEB
type of mainstream |
incorporates partition to direct gas flow thru the neb to pick up the particles
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how does a metered dose inhaler work
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med and compressed inert gas are in a metal container w/ a built in jet nozzle
plastic actuator opens the jet when pressed into the container delivered particle six 2-5 microns 10% of the dose reaching distal airways |
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advantages of a metered dose inhaler
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compact,portable,simple, inexpensive
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how to use a metered dose inhaler
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open mouth wide so teeht or tongue dosn't obstuct
hold 1in away from lips actuate aerosol just after starting an inhalation entrain aerosol in inspiratiory flow inhaling slowly and deeply hold breath for 10-15 secs |
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what do aerochambers do
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slow aerosol down so less impacts in the back of throat
enables pt to better coordinate breath,some have built in whistle to indicate too fast inpiratory flow. |
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how to use a closed mouth metered dose inhaler
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seal lips around canister outlet
inpiration begins actuate the MDI continue to breath in to deep breath use breath hold |
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disadvantages of metered dose inhaler
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propellent ins't inert
and have been implicated in cardiac arrythmias and suddent death with hypoxemia pt can abuse mdi using it to much,canister rupture do to heat,pt must be coordinated and strong enought to actuate |