Chap 15 Hess Exam Flashcards
Mucosal lining of nose, sinuses, trachea, and bronchi Aid in
heating and humidifying inspired gases
During expiration, the expired gas
transfers heat and humidity back to the mucus lining of the upper airway.
Isothermic Saturation Boundary. Body Temp Pressure saturation
Normally present 5cm below the carina, 100% relative humidity at 37 deg celsius
Factors that can cause a shift
mouth breather, artificial airway, increased minute ventilation, drop in environment temp and humidity
Norm temp and humidity in Pharynx
29-32’C, 95% RH, 28-34 mg/L
Norm temp and humidity in airway opening (nose and mouth)
20-22’C, 50% RH, 10 mg/L
Norm temp and humidity in Trachea
32-34’C, 100% RH, 36-40 mg/L
Norm temp and humidity in Isothermic saturation
37’C, 100% RH, 44mg/L
Hazards and Complications of insufficient humidity
loss of heat and water, Ciliary motility is reduced, airway become irritable, mucus prod increases, pulmonary secretions become thick due to dehydration, tracheal epi can be damaged when upper airway is bypassed
as long as the inspired humidity is at least what %BTPS, no injury occurs in normal lungs
60%
Goals of Humidity Therapy
To provide adequate heat and humidity, to treat hypothermia, to prevent airway response to cold air, to aid removal of thick secretions
For premature and newborn infants, a neutral thermal environment should be
maintained
Bubble Humidifier
dry gas is directed toward the bottom of a water filled reservoir, where the stream of gas is broken up (diffused into bubbles
Passive Humidifier
uses exhaled heat and moisture to humidify inspired gas
Active Humidifier
adds water or heat or both to inspired gas
nebulizer
produces aerosol, or suspension of particles in gas
How to improve humidity delivery
Temp, Surface area, contact time
Temp in improvement of humidity delivery
Greater the temp, the more water vapor it can hold
Surface area in improvement of humidity delivery
Greater the area of contact, greater the opportunity for evaporation
Contact time in improv of humidity delivery
greater the contact time, greater the opportunity for evaporation
Bubble humidifier= water vapor=
nasal cannula
Passive=HME=
Water vapor
Active= passover and wick= heated=
mechanical ventilation or non-invasive ventilation (high flows of dry medical gas are delivered to the patient)
Aerosol bland- sterile water for inhalation=
continuous aerosol (air entrainment large volume nebulizer)
Aerosol Bland- Normal saline, hyper or hypo tonic saline=
Induce sputum= small volume neb for intermittent therapy
Aerosol for medication delivery-
to treat lung disease or complications= SVN for intermittent therapy
Bubble Humidifier
Oxygen passes through sterile water, picks up humidity. NEVER HEATED. Added to NC- 4lpm or greater. Efficiency decreases with increase of O2 flow. Pop off valve warns of obstruction
Pop off valve
warns you off obstruction in bubble humidifier
Bubble humidifier NC LPM
4LPM or greater
Can you heat bubble humidifier
NEVER, because condensation would build up in small bore tubing
HME (heat moisture exchange)
Artificial nose, captures expired moisture and is delivered during the next inspiration, 70% efficient, problems of occluding filter with secretions, position is crucial, mainly used inline on the ventilator
How efficient is an HME
70%
Active Humidity types
passover, bubble humidifier, Jet nebulizer
Passover - Reservoir
Most commonly used with mechanical ventilation and noninvasive ventilation
How Passover - Reservoir is used
gas flow passes over a reservoir of water, water evaporates into the gas, increasing the humidity of the gas, efficiency is increased by adding heat
Local Brand name for Passover Reservoir
Fisher Paykel
Heated Wire Circuit
Heating wires, Temp probes, passover reservoir, heater, sterile water for inhalation, correct expiratory filter
Wick
Cylinder of absorbent material
Passover wick humidifier
Water wicks up the side, is heated and evaporates into the inspired gas being delivered to the patient,
Concha-
made by Hudson RCI (passover wick humidifier)
Delivered through high flow large bore tubing devices (heated or cool humidity) examples
Heated- ventilators, non-invasive ventilators, heated high flow NC
Delivered with bubble humidifier (heated or Cool humidity)
Cool
Used when upper airway is bypassed ETT or tracheostomy tube (heated or cool humidity)
Heated Humidity
Used when high flows delivered exceed the bodies ability to heat and humidify dry inspired medical gases (HFNC) - heated or cool humidity?
Heated Humidity
Delivered with continuous aerosol set up- heated or cool humidity?
Cool humidity
Used to treat inflammation of the upper airway- heated or cool humidity?
Cool humidity
Used to treat hypothermia- heated or cool humidity?
Heated humidity
Aerosol Therapy
Consists of liquid particles suspended in a gas
Bland aerosol consists of
sterile water for inhalation (continuous aerosol), Isotonic Saline, Hypertonic Saline, Hypotonic Saline
Air entrainment large volume jet neb
Liquid is shattered into particles, large unstable particles rain out, small stable particles are delivered to the patient. You can add heat
Can you add heat to Air entrainment large colume jet nebulizer
Yes
Ultrasonic Neb
Uses piezoelectric crystal to generate aerosol, converts radio waves into high frequency mechanical vibrations, create very high output of aerosol particles, used for bland aerosol delivery
Recently- what is found in homes as room humidifiers
Ultrasonic Nebs
Coverts radio waves into high frequency mechanical vibrations
Ultrasonic neb
Indications for bland aerosol
upper airway edema, postextubation edema, bypassed upper airway, need for sputum or mobilization of secretions, croup
Assessment of need for bland aerosol
stridor, croup like cough, hoarseness following extubation, bypassed upper airway
Bland Aerosol, sputum induction involves
Short term delivery (approx. 15-30 min) of hypertonic saline (3-10%) aerosol via small volume neb
Assists in mobilizing secretions
increased volume of fluid in airway, cause irritation which stimulates couch, pt expectorates sputum into specimen cup to be sent to the lab for a culture and sensitivity test
How the particles fall
Impact, Sedimentation, diffusion
Impact
effective filter of the upper airway, particle sizes 10 microns or greater
sedimentation
aerosol particles fall due to gravity, primary mechanism for particles sizes 1 to 5 microns
diffusion
when gas flow ceases, aerosol particles collide and deposit on alveolar cell surfaces
Deposition Particle size
Unaided eye cannot see particles less than 50-100 microns (um)
VMD
Volume median diameter- laser diffraction
MMAD
Mass median aerodynamic diameter- cascade impaction
heterodisperse
term used to describe resp aerosols with the particles of all different sizes
In an aerosol distribution with a specific MMAD, what % of the particles are small and have less mass and what percent are larger and have greater mass
50%, 50%
Determinants of deposition
particle size, inspiratory flow rate, flow pattern, RR, Inhaled volume, I:E Ratio, Obstruction
Upper airway particle size (MMAD)
5 to > 50 microns
Lower airways particle size (MMAD)
2 to 5 microns
Parenchyma: alveolar region particle size (MMAD)
1 to 3 microns
Parenchyma particle size
<0.1 microns
Hazards of Aerosol therapy
Nosocomial infections, adverse reaction to med being delivered in aerosol form, cool aerosol can cause bronchospasms, wheezing, precaution when delivery to infants, drug concentration may increase
Drug concentration increase usually seen with
continuous aerosol drug delivery
Bronchospasm and bronchoconstriction
abnormal contraction of smooth muscle in the conduction small airways resulting in acute narrowing and obstruction
Aerosol drug delivery systems
MDIs, DPIs, SVN=HHN, LVN, Ultrasonic neb, plus more
MDI- Metered dose inhalers
Pressurized canister, contains prescribed drug and propellant, HFA, Aerosol prod takes approx 20 millisec, initially particle size is 35 microns. the propellant evaporates and particle size becomes smaller
Most commonly ordered method of delivery
MDI- Compact portable relatively easy to use. commonly misused by patients
Preferred method for delivery bronchodilator therapy to spontaneously breathing pts and pts who are mechanically ventilated
MDI
MDI Particle size delivered
3-6 microns
MDI pulmonary deposition ranges between
10-20%
How much of MDI deposits in oropharynx
80%.. medication swallowed in turn entering systemic circulation
Before initial use- MDIs should be
primed by actuating the device 1 to 4 times
All new MDIs are required to have a
counter which keeps track of actuations (puffs) left
MDI techniques
warm canister, shake, prime, breathe out normally, slowly breath in, continue inspiration to TLC, hold breath for up to 10 secs, wait one min between puffs
Wait how long in between MDI puffs
one minute
Open mouth MDI technique
open wide, keep tongue down, place canister 4cm (2fingerbreaths), this improves deposition by reducing oroparyngeal rain out (impaction)
Closed mouth MDI technique
place mouthpiece between lips with tongue out of the path of the outlet
Breath actuated MDIs
Removes: actuation to inspiration timing technique complication…. inspiratory effort activates aerosol delivery
Spacers reduce
oropharyngeal impaction and the need for precise actuation/ inspiration coordination.
what kind of particles impact on spacer walls
large
ALL spacers add
distance between the MDI and the mouth
Holding chambers
Spacer which contains a one way valve, holds med in chamber until there is no inspiratory effort, can take 2-7 breaths with one actuation (6-10 for children), can attach a mask, has a training whistle
Dry powdered inhaler (DPI)
Breath actuated, med is in powder form, dispersion is dependent on turbulent flow, carrier substance is used(lactose or glucose)
What affects DPIs drug delivery
humidity
DPIs require what kind of inspiratory flow
High inspiratory flow
DPIs % delivered to respiratory tract similar to MDIs
10-20%
DPIs particle size
Dry powder (med): 1-3 microns, Propellant (carrier); 20-65 microns
Most of the DPIs carrier is deposited in
oropharynx
DPI Technique
Assemble, Load Dose, Exhale slowly to FRC, Seal lips around mouth piece, inhale deeply and forcefully, breath hold (10 sec), Repeat process until dosage complete
Liquid = aerosol (MDI or DPI)
MDI
Solid= aerosol (MDI or DPI)
DPI
Can use spacer / chamber (MDI or DPI)
MDI, spacer isnt needed for DPI
Must be able to take a slow deep breath and hold (MDI or DPI)
MDI
Must create turbulent inspiratory flow (MDI or DPI)
DPI
Oral deposition compared to other without spacer
DPI
Must keep track of doses (MDI or DPI)
MDI, DPI has a counter or are indiv wrapped
Coordinate delivery of dose and inspiration (MDI or DPI)
MDI, DPI is no coordination involved
Small volume neb (SVN) HHN
Delivers aerosolized medication or bland aerosol!, small= holds less than 10mls, Pneumatically powdered, 10 psi at home (electric compressor)
Pneumatically powered
which means they are powered by a pressurized gas source (50PSI in hospital)
Electric Compressor
10psi at home
How is aerosol produced
high pressure stream of gas shot through a restricted orifice, the liquid is drawn up a capillary tube created by low lateral pressure, the liquid then passes over the jet and is shattered
Aerosol particle size
is b/w 0.1 to 500 micron range
Liter flow is inversely proportional to
droplet size and neb time (treatment time)
higher the liter flow, what the droplets, and treatment time
higher the liter flow, smaller the droplets, shorter the treatment time
for neb treatments in hospital with a 50 psi gas source the liter flow used is
6-10 L/m (usually always 10)
Deposition for nebulizer treatment
12% or less, 2% in infants
Infants are natural
nose breathers
Delivering aerosol to infants and children
well fitting aerosol masl vs. mouth piece, blow by, never to crying baby
Breath actuated neb
only produces aerosol during inspiration, increases treatment time, aerosol production is triggered with inspiratory flow
If the patient is unable to generate enough flow for and adequate period of time usuing a breath actuated neb
the treatment will be ineffective
Bronchodilator
reverses bronchoconstriction, opens up the airway
corticosteroid (inhaled)
Reduces inflammation in lung only, may enhance bronchodilator, can cause oral thrush
Mucolytic
thins or breaks up secretion
antibiotic
treats bacterial infections
Mouthpiece vs Mask issue
Patient ability, preference, and comfort
Aerogen neb
uses electricity not flow
Large volume neb
heart/ hope, mini heart
How are we going to assess patient response, how should a patient improve
aeration
