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MOD II TECH

Terms

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def

humidity
water in a gas vapor
molecular water in gas
def absolute/ actual humidity
actual amt of water content of gas fully saturated
**(44mg/L)**
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
partial pressure at body temp of 37 degrees celcius
47 torr or mmHg
def relative humidity
ratio of content (AH)/capacity (PH) or
content/potiential_RH
relative humidity capacity
when gas contains all the H2Oit can it is saturated. temp increases, capacity increases
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
body humidity is ____torr?
47 or 44mg/L
def
condensation
when cooling occures h2o changes from vapor to liquid. paricles can be reborn
def
dew point
temp at which h20 vapor condenses to liquid
def
evaporation
h20 moving from liquid to gas
def
coalescence
particles grow by absorption
def
rain out
particles leave suspension settling occurs due to gravity (cold room warm humidifying tube)
def
penetration
the max depth to which particles can be carried (down to alveoli)
def
deposition
instability of aerosol which permits rain out (deposition up high)
def
retention
the depositon of particles at a specific location within the resp tract
def stability
the ability of aerosol to remain in suspension over a period of time
what is stability effected by

(aerosol stability)
size and nature of aerosol particulate,
concentration of particles present,ambient humidity,mobility of carrier gas
water vapor content and pressure
room temp
77 F 25 C
partial pressure 23.69 torr
capacity 23.04 mg/L
water vapor content and pressure

body temp 98.6 F 37 C
partial pressure
47 torr
capacity 43.8 mg/l
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,
4 indications for humidity therapy?
retained secretions
mucus plugging
bronchospasm caused from dry air, irritation to airway
3 functions of the nose?
heat, humidify and filter inspired air
how much h20 may the nose add to the air a day?
1000 ml a day
what percentage of RH is at the nasopharynx?
75%-80%
how does the nose warm
copius capillary blood flow allows for transfer of heat to inspired air
how does the nose filter?
a combo of lrg hair follicles and mucus layer atop the mucosa
inadequate humidification leads to???
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
3 catagories of humidifiers?
simple
heated and hygroscopic condenser (HME heat moisture exchange)
3 ways humidity is quantified?
actual/absolute
partial pressure
relative humidity
how does the simple humidifier work?
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
how does the bubble humidifier work?
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.
what kind of pt uses a bubble humidifier
a pt with intact upper airways who need supplemental humidity (intact means no holes)
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
how does a underwater jet humidifier work
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
3 factors that influence humidifier efficiency
temp, contact time and surface area
3 types of simple humidifiers
bubble and jet humidifier & underwater jet humidifier
how does a jet humidifier work
produces and aerosol but the baffles remove lrg particles. incrases both time and surface area contact
how do heated humidifiers work?
body humidity levels are needed heat must be applied. tubing may be heateddecreased temp from humidifier and mini
tubing may be heated, heat wire circuits allow ???
decreased temp from humidifier and minimizes condensation
what kind of pt can a wick humidifier be used on?
at 100% RH at body temp can be used on intubated pt
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
capablility and limitation of wick humidifier?
adv:saturation can be maintained even at continuous high flows creating greater efficiency
less resistance to flow demand from the pt. (decreased WOB)
def
aerosol
particles suspended in gas
can be solid but is usuall liquid
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)
factors influencing depositon in airways??

GRIT PP
gravity
random motion-kineticactivity
inertia
temp
physical nature
pt ventilatory pattern
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
fyi increase mass=increase inertial impaction
fyi: increase temp=kinetic energy increases
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
temp in reference to aerosols
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
aerosol jtf:hydroscopic particle has tendency to absorb water which will increase size and mass (early rain out)
solutes in h20 jtf:hypertonic particle will gain water
solutes in h20 jtf:hypotonic will lose water
solutes in h20 jtf: electrical charge has little effect on solutes in solutions
what kind of ventilatory pattern will increase aerosol penetration into the lung
slow deep breath followed by a pause (3-5sec)before exhalation
3 goals of aerosol therapy
improve bronchial hygiene
humidify delivered gases
deliver medications
to improve bronchial hygiene what do you use to mobilize secretions
use bland solution(h20,NaCl or sodium bicarb)
diagnose bronchial hygiene need
sputum induciton specimen for gram stain,C&S to determine pathogen or cytology to determin cell type for malignancy
advantage of aerosol therapy delivery?
aerosol route always available, direct deposition to target site. smaller dosage,faster onsite ,decreased systemic side effects
disadvantage of aerosol therapy delivery?
dosage of drug is difficult to estimate
pt compliance required
aerosol therpy particle size measured in ?

size determines?
microns

depth of penetration and stability
aerosol therapy jtf: smaleer the particle size the greater the depth of penetration
aerosol therapy jtf:particles larger than 10 microns are deposited in the upper airway by nasal filtration
aerosol therapy particle output volume is measured in
ml/min or ml/hr or cc/min or cc/hr
factors that control aerosol therapy particle output ???
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
4 hazards of aerosol therapy
cause bronchospasm
increase airway obstruction
systemic fluid overload (in infants)
cross contamination
how can aerosol therapy cause airway obstruction?
hydrophilic(water loving)secretions swell when they absorb water and result in lower airway obstruciton
how can aerosol therapy cause bronchospasm?
aerosol droplets are foreigh bodies can precipitate bronchospasm
4 aerosol delivery devices
aerosol masks, face tent, t piece, briggs adaptor and trach mask or collare
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
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
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
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
the purpose of aerosol generator nebulizer (3)
repiratory tract humidification, mobilization of secretions,delivery of meds
2 ways nebulizers are catagorized
pneumatic-gas powered

electrically-powered with electric current
how does the aerosol generator nebulizer work
uses venturi & bernouilli principal. uses gas source, capillary tubes and baffles
what is a baffle??
any object placed in the path of aerosol particles.
why use a baffle on a neb?
reduces the ave size of aerosol particles by removing larger ones
5 types of gas powered nebs
lrg vol jet neb
hydronamic (babbington)
sm vol jet neb
MDI-metered dose inhaler
SPAG-small particle aerosol generator
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
on a lrg volume neb what kind of 3 aerosol devices are used?
face mask, face tent, t piece or trach collar
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????
fio2 is decreased
neb entrainment ratios

100%
0:1
neb entrainment ratios

60%
1:1
neb entrainment ratios

40%
3:1
neb entrainment ratios

35%
5:1
neb entrainment ratios

30%
8:1
what happens if the flow from the neb unit is inadequate?
density AND fio2 drop due to increased air entrainment by the pt
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.
jtf neb:if the total flow from the unit does not meet the pt inspiratory flow demands the aerosol denisty and fio2 will drop
air dilution increases aerosol but.....
aerosol density decreases (decreasing RH)
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
4 possible heated neb precaustions
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.
4 types of neb heaters
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)
hydrodynamic babinton, hydrosphere, solosphere nebulizer
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
3 types of electric ultrasonic large volume nebs
DeVibiss
Monaghan
Mistogen
goal of the electric ultrasonic large volume nebs
to produce a very dense mist with a water content greater than 100mg/L
output of the electric ultrasonic large volume nebs and particle size
3-6ml/min (depending of model)
90% withnin .5-3 micron range
indications of the electric ultrasonic large volume nebs
aid in the mobilzation of secretions and med delivery
how does the ultrasonic neb work??
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
4 hazards of untrasonic nebs
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
why use an untrasonic neb?
intermittent use
use to induce sputum
home use to replace steam vaporizer
aerosol medication delivery
(SPAG)small particle aerosol generator specially designed for ???
delivery of anti viral agents (ribavirin, virazole) for infants with RSV bronchiolitis
SPAG small particle aerosol
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
sm vol neb advantages
(hand held)
aerosol route is alway avail
direct to target site
minimum dosage therefore decreased side effects
sm vol neb disadvantages
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
sm vol neb aerosol delivery method
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)
types of sm vol nebs
mainstream
sidestream
slip stream
mainstream sm vol neb
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)
sidestream sm vol neb
aerosol drips or is injected into main gas flow
produces sm particles
more particles rain out so output is less
slip stream NEB
type of mainstream
incorporates partition to direct gas flow thru the neb to pick up the particles
how does a metered dose inhaler work
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
advantages of a metered dose inhaler
compact,portable,simple, inexpensive
how to use a metered dose inhaler
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
what do aerochambers do
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.
how to use a closed mouth metered dose inhaler
seal lips around canister outlet
inpiration begins actuate the MDI
continue to breath in to deep breath
use breath hold
disadvantages of metered dose inhaler
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

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