humidity and aerosol therapy
What is the optimal particle size?
1 to 5 microns
Parenchyma: alveolar region
1-3 um
lower airway deposition
2-5 micrometers
What is the optimal size for particles passing through the large-volume jet nebulizer?
2-5 micrometers.
MDI can produce aerosols particles what size?
2-6 um
How much can an unheated large volume nebulizer put out?
26 - 35 mg H2O/L
Unheated large-volume jet nebulizers can produce how much?
26 - 35 mg/H2O/L
How much humidity is recommended for intubated patients?
30 mg/L
Heated large-volume jet nebulizers can produce how much?
35 - 55 mg/H2O/L
To maintain airway temperatures by humidification the temperature has to range between what? .
35 and 37 degrees Celsius
Inhaled gas is supposed to be maintained at what temperature?
35-37 degrees C
The physician orders continuous bronchodilator therapy with 1:200 albuterol for an asthma patient at a dosage of 20 mg/hr. How much 1:200 albuterol will be needed for the 1st hour of the treatment?
4 mL
DPI patients must have inspiratory rates of at least what?
40-60 l/min
5. What is the expected body humidity value at normal body temperature? 44 mg/L
44 mg/L
What is the capacity of water at body temperature?
44 mg/L
What is the formula for humidity deficit?
44 mg/L - absolute humidity
Upper Airway Deposition (nose, larynx, trachea)
5-50 micrometers MMAD
What is the optimal flow rate and amount of solution to put in an SVN?
6 to 8 L/minute.
Normally, when using a 50-psi flowmeter to drive a SVN, you set the flow at what?
6-8 L/minute.
29. What is the expected water vapor output of bubble humidifier?
80%
What is a technical downfall of MDIs?
80% of the aerosol hits the back of the throat depositing the medication in the oropharynx.
parenchyma deposition
<0.1 um
adverse reaction classified as what?
>20% change in HR
What kind of solution is used in sputum induction?
A 3- 10% hypersonic saline solution is used.
What type of humidifier breaks an underwater gas stream into small bubbles? .
A bubble humidifier
What is a humidifier?
A device that adds molecular water to a gas, occurring by the evaporation of water from a surface.
What is the definition of a Nebulizer?
A device that produces an aerosol suspension of liquid particles in a gaseous medium using baffling to control particle size.
What type of humidifier directs gas over a water surface?
A passover (blow-by) humidifier.
What is a Metered-dose inhaler (MDI)?
A pressurized canister containing the prescribed drug in a volatile propellant combined with surfactant and a dispersing agent.
What type of humidifier is normally used for mechanical ventilation?
A reservoir humidifier.
What's the difference between spacers and holding chambers?
A spacer is valve-less and just adds distance from the point of discharge to the mouth. A holding chamber has valves for holding the medication.
What is the baffle?
A surface on which large particles impact and fall out of suspension, whereas smaller particles remain in suspension, reducing the size of particles remaining in the aerosol.
What is an aerosol?
A suspension of solid or liquid particles in a gas.
What is a Breath-Actuated Pressurized Metered Dose Inhaler?
A variation of a pMDI that incorporates a trigger that is activated during inhalation. This trigger reduces the need for the patient or caregiver to coordinate MDI actuation with inhalation.
What type of humidifier does not have bubbles or aerosol and has a tube coming out the top end?
A wick humidifier.
22. What are the hazards of using a bubble humidifier?
At a high flow rate, it can produce aerosols which can transmit pathogenic bacteria from the humidifier reservoir to the patient.
What amount of humidity is used for intubated patients?
At least 30 mg/L.
What is the Isothermic Saturation Boundary?
At or below carina, the point where inspired gases are fully saturated and warmed to body temperature.
What are the high flow humidifiers?
Heated bubble, passover, wick, vapor phase, capillary force, membrane type, and HME.
What is an ultrasonic nebulizer capable of?
Higher aerosols outputs and higher aerosol densities than conventional jet nebulizers.
What are the types of heating elements that require an electrical source?
Hot plate, wraparound, yolk or collar element, immersion type, and a heated wire-ventilator circuit.
What is aging? .
How long the particle is suspended before it gets to the target site
What is deposition?
How the particle lands. The size determines how it deposits. It's affected by inertia, sedimentation, and brownian movement.
What is a device that adds molecular water to gas?
Humidifier
. What are the indications for humidification therapy?
Humidifying dry medical gases/flows greater than 4 l/min, overcoming humidity deficit created when upper airway is bypassed, managing hypothermia, and treating bronchospasm caused by cold air.
What piece of equipment is used to measure humidity?
Hygrometer
With prolonged breathing of improperly conditioned gases through the tracheal airway, this can result in what condition?
Hypothermia
Heated humidifiers operating continuously in breathing circuits can evaporate how much per day?
More than 1L H2O per day.
What are some of the Advantages of a spacer? .
No need to activate coordination with inspiration, Increases drug deposition in the lungs, Reduces drug deposition in the mouth, Can be used in children with a face mask, and Decreases the incidence of oral thrush
Are bubble humidifiers normally heated?
No, no they are not.
Do passover humidifiers have a high efficiency and high exposure time?
No, they have low efficiency and low exposure time.
Sedimentation
Occurs when aerosol particles settle out of suspension & are deposited owing to gravity. -The greater mass of the particle the faster it settles. primary mechanism for deposition of particles 1-5 micrometers
What is the fundamental principle of aerosol deposition?
Only a fraction of the emitted aerosol will be inhaled and only a fraction of what is inhaled will make it to the lungs.
Possible complications associated with the selection of an aerosol drug delivery device include all except:
Overhydration or fluid imbalances.
What is inertia?
Particles collide and burst resulting in rainout and less medication to the site of action. Turbulent flow can cause this.
What kind of patients use a Passover humidifier?
Patients on home CPAP units or those in the neonatal nursery.
Heating systems are usually used for what type of patients?
Patients with bypassed upper airways and those on mechanical ventilation.
33. What are the advantages of the wick and membrane Passover humidifiers?
They can maintain saturation at high flow rates, they add little or no flow resistance to spontaneous breathing circuits, they do not generate any aerosols posing minimal risks for spreading infections.
What does an HME do?
They capture exhaled heat and moisture which is then applied to the subsequent inhalation (they hold the patient's own heat and water).
What are unit-dose DPIs?
They dispense individual doses of the drug from punctured gelatin capsules.
What are the medication delivery issues for infants and children?
They have smaller airway diameters, faster breathing rates, nose breathing filters out large particles, lower minute volumes, and spontaneous patient cooperation can be an issue.
What do high flows in mist tents help to do?
They help to "wash out" CO2 and reduce heat buildup.
62. The CDC recommends that nebulizers should be what?
They should be cleaned and disinfected, or rinsed with sterile water, and air-dried between uses.
64. What is the process of cleaning holding chambers and spacers?
They should be cleaned regularly, typically monthly, as recommended by the manufacturer. Use of dilute liquid dishwashing soap, with or without rinsing, and allowing to air dry are recommended.
Before initial use and after storage, every pMDI should be what?
They should be primed by shaking and actuating the device to atmosphere one to four times. Without the priming, the initial dose actuated from a new pMDI canister contains less active substance than subsequent actuations. You should waste a single does when it has not been used for 4-6 hours.
DPIs should not be used for what?
They should not be used for the management of acute bronchospasm.
How do Jet Nebulizers work?
They use a capillary tube to draw water and a jet to create a baffle in which water is shattered into liquid particles often larger particles will fall out smaller ones are carried to the patient.
39. What are the three types of HMEs?
Simple (high thermal conductivity) Condenser humidifier, Hygroscopic (low thermal conductivity) Condenser humidifier, and Hydrophobic (water repellent element) Condenser humidifier.
What is an optimal breathing pattern?
Slow laminar flow with gentle, deep breaths.
40. What are the needed characteristics of an HME?
Stable and provides heat and moisture to the patient.
What happens below the ISB?
Temperature and relative humidity remain constant.
What factors influence condensation?
Temperature difference across the system, ambient temperature, gas flow, set airway temp, and length, diameter, and thermal mass of breathing circuit.
27. What are the factors that influence the output of a bubble humidifier?
Temperature, Relative humidity, and absolute humidity.
20. What are the four variables that affect the performance of a humidifier?
Temperature, surface area, time of contact, and thermal mass
What are the factors that affect a humidifier's function?
Temperature; the higher the temperature of a gas, the more water it can hold; surface area, time of contact, thermal mass; the greater the amount of water in humidifier, the greater the thermal mass.
What type of humidifier is known as the "artificial nose?"
The HME.
What is the SPAG?
The SPAG was manufactured by ICN Pharmaceuticals specifically for administration of ribavirin (Virazole) to infants with respiratory syncytial virus infection. It incorporates a drying chamber with its own flow control to produce a stable aerosol.
12. What is absolute humidity?
The actual amount of moisture contained in a gas.
13. What is relative humidity?
The amount of water vapor a sample could maximally hold at a given temperature.
14. What is body humidity?
The amount of water vapor in a gas sample compared to the capacity for water vapor at body temperature.
What best describes humidity deficit?
The amount of water vapor needed to achieve full saturation at body temperature.
26. What is wrong when no bubbling occurs with a bubble humidifier?
The capillary tube could be obstructed, loose connections, O2 flow may not be turned on, or inadequate pressure in the line.
Aging depends on what?
The composition of aerosol, initial size of particles, time in suspension, and ambient condition which it is exposed.
What contributes to aging of aerosols?
The composition of aerosol, the initial size of particles, the time in suspension, and the ambient condition.
Temperature is an important factor affecting humidity due to the fact that the greater the temperature of the gas, the more what?
The more H2O vapor it will hold.
The higher the temperature of the gas in the humidifier? .
The more water it can hold
What is the most effective humidifier/heater on the body?
The nose.
25. What is wrong if the bubble humidifier whistles by itself? .
The oxygen flow may be too high or the tubing may be kinked/obstructed
What is Brownian diffusion?
The primary deposition mechanism for very SMALL particles and will deposit DEEP within the lungs.
What is Brownian Diffusion?
The primary mechanism for deposition of small particles (less than 3um), mainly in the respiratory region where bulk gas flow ceases.
What is aerosol aging? .
The process by which an aerosol suspension changes over time
What is aging when pertaining to aerosols?
The process by which the aerosol suspension changes over time.
What is relative humidity?
The ratio between the amount of water in given volume of gas and maximum amount it is capable of holding at that temperature.
What is relative humidity?
The ratio of how much water a gas sample is actually holding.
What are 3 factors that determine particle size?
The substance being nebulized, the method used, and the environmental conditions.
What happens above the ISB?
The temperature and relative humidity decrease during inspiration, and increase during exhalation.
What happens to the temperature of a solution placed in an ultrasonic nebulizer?
The temperature of the solution increases.
3. Heat and Moisture exchange is a primary function of what?
The upper respiratory tract, mainly the nose.
In bubble and passover humidifiers, heat improves what?
The water output (absolute humidity).
What is absolute humidity?
The weight of the moisture. The amount of water in given volume of gas. It is expressed in mg/L.
In order for evaporation to occur, what are the ideal conditions that need to be present?
There needs to be a large surface area to enable evaporation to take place.
What type of probe does the Servo-controlled heating system use at or near the patient's airway?
Thermistor probe.
What are heterodispersed aerosols?
They are aerosols with particles of different sizes.
What are cascade impactors?
They are designed to collect aerosols of different size ranges on a series of stages or plates.
How are large-volume jet nebulizers powered and what are they connected to?
They are pneumatically powered and are connected directly to a flowmeter.
Following the intubation of a patient, it is indicated that the patient needs?
They will need humidification and warming of inspired gases.
What does the term Inspissated refer to?
Thickening of secretions due to dehydration.
What are humidifiers used for?
To add molecular water to gas
What is the purpose of a room humidifier?
To help with sinusitis and drainage.
9. What is the primary goal of humidification?
To maintain normal physiologic conditions in the lower airways.
16. What are heaters used for in humidity therapy?
To prevent or treat various abnormal conditions such as hypothermia or alleviating bronchospasms.
What is the goal of a bubble humidifier?
To raise the water vapor content of the gas to ambient levels.
What are the goals of humidity?
To reduce airway swelling, the removal of thick secretions, and to prevent the airway response to cold air.
28. What is the purpose of a pop-off valve in a bubble humidifier?
To warn of flow path obstruction and to prevent bursting of the humidifier bottle, it releases pressures greater than 2 psi.
What is turbulent low?
Turbulent flow is a function of the ability of the patient to inhale the powder with a sufficiently high inspiratory flow rate.
What device is electronically powered and uses a piezoelectric crystal to generate aerosol?
Ultrasonic nebulizer.
What is the primary hazard of aerosol drug therapy?
Untoward drug reactions.
during noninvasive ventilation,what is considered to deliver a greater inhaled dose, SVN or VM
VM
What can be used to minimize the risk of inhalation of condensation?
Water traps or heated circuits.
respirable dose
a fraction of the inhaled dose is deposited in the lungs
primary hazard of aerosol drug therapy is?
adverse reaction to medication
Respimat
albuterol/ipratropium pneumatic (jet) nebulizer
inhaled mass
amount of drug inhaled
positive response in continuous neb is indicated by what?
increase in PEFR of at least 10% after the first hour of therapy, goal is at least 50% of predicted value
Diskus, flexhaler and twisthaler are all examples of what?
multiple dose drug reservoir DPI
Inertial impaction
occurs when suspended particles in motion collide with and are deposited on a surface -this is the primary deposition mechanism for particles larger than 5um
what happens if a baby cries during treatment?
treatment should be stopped, crying reduces lower airway deposition of aerosol medication
What is the formula for relative humidity?
%RH = content/capacity x 100
What are the three most common humidifiers used in Respiratory care?
(1) Bubble humidifiers, (2)Passover humidifiers, and (3)Heat and moisture exchangers.
What are two specific problems that are associated with SPAG use to deliver ribavirin?
(1) Caregiver exposure to the drug aerosol, and (2) Drug precipitation can jam breathing valves or occlude the ventilator circuit.
What are two methods to measure medical aerosol particle distribution?
(1) Cascade impaction, and (2) Laser diffraction
What are the three most common problems with humidification systems?
(1)Dealing with condensation, (2) Avoiding cross-contamination, and (3)Ensuring proper conditioning of the inspired gas
Name two devices that are used to deliver bland aerosols?
(1)Large-Volume nebulizers, and (2) Ultrasonic nebulizers.
What are some factors that would influence the amount of condensation in a humidified system?
(1)Temperature difference across the system, (2) Ambient temperature, (3) Gas flow, (4) Set airway temperature, and (5) The length, diameter, and thermal mass of the breathing circuit.
Brownian diffusion
- Primary deposition mechanism for very small particles (<3 um) deep within lung - Particles between 1 and 0.5 um have very low mass and are so stable that most remain in suspension and are exhaled back into environment - Particles >0.5 um have greater retention rate in lungs
intrapulmonary percussive ventilation
- Provides high-frequency oscillation of airway while administering aerosol particles - Aerosol generator should be placed in circuit as close to patient's airway
Vibrating mesh nebulizer
-Compared to USN, reduction of residual drug volumes is left in the nebulizer, creating saving when administering expensive meds. -Particle size produced is 2-3 and has a much shorter delivery time.
where does an aerosol generator go on a patient on mechanical vent?
18 to 24 in from the patient in the inspiratory limb
38. What is the correct placement of an HME?
10 cm away from the endotracheal tube and proximal to the ventilator circuit.
On average, what % of an aerosol drug delivery device's output actually deposits in the lungs?
10%-20%
18. How does a heater improve the effectiveness of a humidifier?
Heat improves the water output of humidifiers.
What is Volume Mean Diameter (VMD)?
The median diameter of an aerosol particle measured in units of volume.
What is the primary role of the upper airway?
Heat-moisture exchange.
What type of humidifier uses a filter?
Heat-moisture exchangers (HME).
What does humidity therapy involve?
Adding water vapor and sometimes heat to the inspired gas.
6. What happens above the ISB?
Above isothermic saturation boundary, the temperature and humidity decrease during inspiration and increase during exhalation.
What is the formula for body humidity?
Absolute humidity / 44 mg/L x 100
2. What does Humidity therapy involve?
Adding water vapor and sometimes heat to inspired gas.
How do you ensure heated circuits are working?
Adjust the temperature differential to the point that a few drops of condensation from near the patient connection or wye
Name four types of airway appliances used with large-bore tubing.
Aerosol mask, Face tent, T-tube, and Tracheostomy mask.
What are the types of aerosol masks?
Aerosol mask, trach collar, t-piece, face tent, mist hoods, and tents for small children and infants.
What are the factors that affect aerosol drug therapy?
Aerosol output, Particle Size, Deposition, Aging, Breathing Pattern, and Physical characteristics of the airway.
What does gravimetric analysis measure?
Aerosol weight.
What are monodispersed aerosols?
Aerosols with particles of similar sizes.
What is a risk that patients are exposed to when inhaling heated gases?
Airway burns.
What is residual drug volume? .
Also known as dead volume, it is the medication that remains in the SVN after the device stops generating aerosol and "runs dry." The residual volume of a 3-ml dose can range from 0.5 to more than 2.2 ml, which can be more than two-thirds of the total dose. Residual volume also depends on the position of the SVN
Where do most aerosol particles that are less than 3 um deposit?
Alveoli
What are breath-actuated nebulizers?
An aerosol device that is responsive to the patient's inspiratory effort and reduces or eliminates aerosol generation during exhalation. They can generate aerosol only during inspiration. This eliminates the waste of aerosol during exhalation and increases the delivered dose threefold or more over continuous and breath-enhanced nebulizers.
What puts stress on the lower airway in order to provide heat and moisture?
An artificial airway.
What is an ultrasonic nebulizer?
An electrically powered device that uses piezoelectric crystal to generate aerosol. Crystal transducer converts radio waves into high-frequency mechanical vibrations that produce aerosol.
Poor patient response to bronchodilator therapy often occurs because what?
An inadequate amount of drug reaches the airway. To determine the "best" dose for patients with moderate obstruction, the respiratory therapist should conduct a dose-response titration.
What is a potential problem with continuous bronchodilator therapy (CBT)?
An increase in drug concentration can be adversely given. Patients receiving CBT needs close monitoring for signs of drug toxicity (e.g., tachycardia and tremor).
What is the Brownian movement?
As you breathe in, airflow slows down. Particles slow down and hit each other causing rain out.
What would you recommend as initial therapy for a patient admitted to ER with acute airway obstruction?
Assess dose response of MDI albuterol (up to 12 puffs), and Provide up to 3 SVN treatment's with albuterol every 20 minutes.
11. What are the clinical signs/symptoms of inadequate airway humidification?
Atelectasis, Dry nonproductive cough, increased airway resistance, increased incidence of infection, increased work of breathing, patient complaint of substernal pain and airway dryness, and thick dehydrated secretions.
How does an atomizer differ from an SVN?
Atomizers don't have baffles. They are usually powered by a hand-squeezed bulb. Because the particles are larger, the drug deposits in the upper airway. You might deliver a local anesthetic through an atomizer prior to bronchoscopy.
What are 3 examples of aerosol devices?
Atomizers, Nebulizers, and Inhalers.
4. Why is the mouth less effective at heat and moisture than the nose?
Because of the low ratio of gas volume to moist and warm surface area and the less vascular epithelium lining in oropharynx and hypopharynx.
Simple large reservoir systems are manually refilled with sterile or distilled water. Why would this be a problem?
Because the system must be opened for refilling where cross-contamination can occur.
7. What happens below the ISB?
Below the isothermic saturation boundary, the temperature and relative humidity remain constant (BTPS).
What consists of liquid particles suspended in a gas (oxygen or air)?
Bland aerosol.
Appropriate documentation when conducting point of care assessment of a patient's response to bronchodilator therapy includes all except:
Blood levels of the bronchodilator agent.
What term describes the primary mechanism for deposition of small particles? .
Brownian diffusion
1. What are the devices that are considered to be a humidifier?
Bubble humidifier can be prefilled or a refillable one, Passover humidifier there are three types a simple, wick, and membrane, Heat and Moisture Exchanger HME/artificial nose, and a Room Humidifier.
What are the types of humidifiers?
Bubble, Passover, wick, HME, and cascade.
What are the low flow humidifiers?
Bubble, and Jet.
What can cause a bacterial colonization in the circuit?
Built-up condensation.
Non-invasive ventilation
CPAP/BiPAP
Where do most aerosol particles in the 1-5 um range deposit?
Central airways.
What are the hazards of condensation?
Condensation can disrupt/occlude gas flow through the circuit altering the FiO2 or ventilation function/both, it can work its way to the patient and be aspirated.
what produces greatest amount of second hand aerosol?
Continuous pneumatic nebulizers
When should an MDI be activated for a ventilator patient?
Coordinate firing the MDI with the beginning of the ventilator inspiration.
What are six problems with bland aerosol therapy?
Cross-contamination and infection, Environmental safety, Inadequate mist production, Over-hydration, Bronchospasm, and Noise.
Diskhaler
DPI multiple unit dose
Indications of an adverse drug response during continuous bronchodilator therapy include all except?
Decreased consciousness.
The aim of medical aerosol therapy is to?
Deliver a therapeutic dose of the selected agent (drug) to the desired site of action.
What device depends the patient's inspiratory effort to dispense the dose?
Dry Powder Inhaler.
What are the indications for humidification and warming of inspired gas?
Dry gases that are at a flow greater than 4 L/min, following intubation of a patient, managing hypothermia, treating bronchospasm caused by cold air.
Aerosol particles can change size as a result of what?
Evaporation or hygroscopic water absorption.
How often is an HME changed?
Every 24 hours.
36. What are the hazards of an HME?
Flow resistance increases after several hours of use for some patients this may be a risk because it causes an increased work of breathing, They add 30 to 90 ml of mechanical dead space causing hypoventilation, underhydration and mucous impaction, ineffective low-pressure alarm during disconnection, mucous plugging causing hypoventilation/gas trapping, hypothermia, or mucous plugging causing increased resistive work of breathing.
The administration of dry medical gases at flows greater than what are necessary?
Flows greater than 4 L/min. are necessary.
30. What liter flows should be used with a bubble humidifier?
Flows of 10 L/min or less.
Why would you use continuous nebulization?
For treatment of refractory bronchospasm. Nebulized albuterol is dosed at 5-20mg/hour.
What factor is most crucial in developing an effective program of aerosol drug self-administration in an adult patient requiring maintenance bronchodilator therapy?
Good patient education.
What is the best way to confirm that an asthmatic patient can properly self-manage a newly prescribed aerosol drug therapy?
Have the patient provide a repeat or return demonstration.
What is one problem that Respiratory Therapists have with mist tents? .
Heat and CO2 buildup
19. When should heat be delivered with large volume nebulizers?
If secretions are thick and hard to remove or the patient's upper airway is bypassed.
How can you tell if the HME is working properly?
If the patient is receiving proper heat and moisture.
When assessing a patient's response to bronchodilator therapy, you notice a decrease in wheezing accompanied by an overall decrease in breath sounds. What's most likely the cause of this?
Increasing airway obstruction.
What are key mechanisms of aerosol deposition?
Inertial impaction, Gravimetric sedimentation, and Brownian diffusion.
Mist tents and hoods are normally used to deliver aerosol therapy to what type of patients?
Infants and children.
What are sub-hazards to aerosol drug therapy?
Infection, airway reactivity, pulmonary and systemic effects of bland aerosols, drug concentration changes during nebulization, and eye irritation.
What risk due to condensation can the patient experience?
Inhalation of condensation.
What is a humidity deficit?
Inspired air that is not fully saturated at body temperature. Anything lower than 44mg/L.
What organization sets the standards for the HME's?
International Organization for Standardization (ISO).
The crystal transducer converts radio waves into what?
Into high-frequency mechanical vibrations that produce the aerosol.
How much deadspace does an HME add?
It adds 30 - 90 mL of deadspace.
21. How does a bubble humidifier work?
It breaks/diffuses and underwater gas stream into small bubbles, gas is directed below water level bubbles back up evaporation occurs providing humidity. The higher the flow the more humidity; the lower the flow, the lower the humidity.
A reservoir on the expiratory limb of the nebulizer does what?
It conserves drug aerosols.
What is bland aerosol?
It consists of liquid particles suspended in a gas; sterile water and sterile saline can be used.
Particle size depends on what?
It depends on the substance that is being nebulized, the methods used to generate the aerosol, and the environmental conditions.
What is a hazard of a room humidifier?
It has the potential to spread infections.
Breath holding after inhalation of an aerosol does what?
It increases the residence time for the particles in the lung and enhances distribution across the lungs and sedimentation.
Heated humidifiers can evaporate more than how much?
More than 1 L/day.
A simple albuterol dose-response titration involves what?
It involves giving an initial 4 puffs (90 mcg/puff) at 1-minute intervals through a pMDI with a holding chamber. After 5 minutes, if airway obstruction is not relieved, the respiratory therapist gives 1 puff per minute until symptoms are relieved, heart rate increases to more than 20 beats/min, tremors increase, or 12 puffs are delivered. The best dose is the dose that provides maximum relief of symptoms and the highest PEFR without side effects.
What is a dry powder inhaler (DPI)? .
It is a breath-actuated dosing system by which a patient creates the aerosol by drawing air through a dose of finely milled drug powder. The dispersion of powder into respirable particles depends on creation of turbulent flow in inhaler
How does an HME work?
It is an artificial nose so it captures exhaled heat and moisture and uses it to heat and humidify the next inspiration it does not actively add heat or water to the system like the nose.
Where is the isothermic saturation boundary (ISB)?
It is normally 5 cm below the carina. This can move up and down depending on how hard the nose has to work. The more work the nose does, the ISB moves down. The less work the nose does, the ISB moves up.
When ribavirin or pentamidine is given, the treatment is provided where?
It is provided in a private room. The room should be equipped for negative pressure ventilation with adequate air exchanges (at least six per hour) to clear the room of residual aerosols before the next treatment. HEPA filters should be used to filter room or tent exhaust, or the aerosol should be scavenged to the outside.
What is absolute Humidity?
It is the actual content or weight of water present in a given volume of gas.
What is the respirable mass?
It is the proportion of aerosolized drug of the proper particle size to reach the lower respiratory tract
How is condensation disposed of?
It is treated as infectious waste and therefore drained into an infectious waste container.
When is an ultrasonic nebulizer used?
It is used for sputum inductions when patients are unable to hack it up after trying breathing treatments of saline with large volume nebulizer.
17. What is cool humidification/bland aerosol used for?
It is used to treat upper airway inflammation from croup, epiglottitis, and post-extubation edema.
When the temperature is increased, the potential humidity is?
It is. also increased
What are servo heaters?
It monitors temperature at or near the patient's airway using a thermistor probe the controller adjusts heater power to achieve the desired airway temperature.
How does a Membrane Passover humidifier work?
It separates the water from the gas stream by means of a hydrophobic membrane causing water vapor molecules to easily pass through the membrane but blocking the liquid water/pathogens.
A preliminary assessment should balance what?
It should balance the need versus the risk of aerosol therapy
5. What is ISB?
It stands for isothermic saturation boundary and is the point normally 5 cm below the carina. The temperature is 37 degrees C and it has 100% relative humidity.
What is BTPS?
It stands for: body, temperature at the pressure to which the patient is exposed and 100% saturated with water vapor.
31. How does a wick Passover humidifier work?
It uses an absorbent material to increase the surface area for dry air to interface with heated water.
Clinical efficacy varies according to what?
It varies according to both patient technique and device design. For these reasons, the best approach to aerosol drug therapy is to use an assessment-based protocol that emphasizes individually tailored therapy modified according to patient response.
What type of humidifier deals with Bernouli's principle?
Jet humidifiers.
What are the most common devices used for bland aerosol therapy?
Large-volume jet nebulizers.
How does a large-volume jet nebulizer work?
Liquid particles are generated by passing gas at high velocity through a small jet orifice.
What is bland aerosol?
Liquid particles suspended in a gas.
What affects MDI performance and drug delivery?
Low temperature decreases the output of the CFC MDI's. Debris build up on nozzle or actuator orifice reduces the emitted dose.
most commonly prescribed method of aerosol therapy is?
MDI
What is the preferred method for delivering bronchodilators to spontaneously breathing and intubated, ventilated patients?
MDI (Metered Dose Inhaler).
To monitor a patient for the possibility of reactive bronchospasm during aerosol drug therapy what should u do?
Measure pre and post peak flow and/or %forced expiratory volume in 1 second, Auscultate for adventitious breath sounds, Observe patient's response, and Communicate with the patient during therapy.
What type of humidifier allows vapor to pass, but not water?
Membrane (hydrophobic membrane)
What are the contraindications of an HME?
Patients with thick, copious, or bloody secretions; patients with an expired tidal volume less than 70% of the delivered tidal volume; patients whose body temperature is less than 32 degrees C; patients with high spontaneous minute volumes greater than 10 l/min; and patients receiving in-line aerosol drug treatments.
Aerosols occur in nature as what? .
Pollens, Spores, Dust, Smoke, Fog, and Mist
How do you minimize condensation?
Position circuits to drain condensate away from the patient, check the circuit often, drain the excess condensate from heated humidifier breathing circuits on a regular basis, place water traps at low points in the circuit, use nebulizers placing them in a superior position, keep the circuit at a constant temperature by insulation, increasing the thermal mass, or using wire heating elements in the circuit.
When should a cool mist be delivered with large volume nebulizers?
Post-extubation stridor, inflammation of the airway/tracheal burns, croup, inflammation of Epiglottis.
Cold air and high-density aerosols can cause what?
Reactive bronchospasm and increased airway resistance.
what are the 4 primary forms of aerosol generator used to deliver aerosol during mechanical ventilation?
SVN USN VM MDI with third party adapter
How does condensation occur?
Saturated gas cools as it leaves the point of humidification and passes through the delivery tubing to the patient as the gas cools its water vapor capacity decreases causing condensation.
Restlessness, diaphoresis, and tachycardia also may indicate what?
Severity of airway obstruction but must not be confused with bronchodilator overdose.
Particle size is inversely proportional to what?
Signal frequency (frequency sound waves: 1.35-1.65)
In the Passover humidifier, what is the purpose of the Hydrophobic membrane?
The membrane-type separates the water from the gas stream.
24. What problems could be wrong with a bubble humidifier if no sound is heard when pinching the tubing? .
The inlet could be clogged, most commonly the jar is cracked/loose, the gasket could be worn or missing, the connection could be broken
What are therapeutic aerosol depositions influenced by?
The inspiratory flow rate, the flow pattern, respiratory Rate, inhaled volume, the I:E ratio, and breath-holding.
What is sedimentation?
The larger the particle, the more effect gravity will have on it. This can cause rainout.
Emitted dose
The mass of drug leaving the mouthpiece of a nebulizer or inhaler as aerosol
Droplet size and nebulization time are inversely proportional to gas flow through the jet?
The higher the flow of gas to the nebulizer, the smaller the particle size generated, and the shorter is the time required for nebulization of the full dose.
What are the hazards of the aerosol created and using jet nebulizers?
The droplets could spread infection, hazards include wheezing/bronchospasm, bronchoconstriction, overhydration, discomfort, caregiver exposure to airborne contagions produced during coughing or sputum induction, edema of the airway wall, edema because of decreased compliance and gas exchange with increased airway resistance, sputum induction with hypertonic saline can cause bronchoconstriction in patients with some pulmonary diseases.
23. When should a bubble humidifier be used?
When a patient is on a nasal cannula or simple mask and flow is greater than 4 l/min or patient complains of a dry nose or irritation in the hospitals the prefilled ones are most common the refillable ones are used in home care settings for patients with oxygen concentrators.
34. When are Wick or Membrane Passover humidifiers used?
When a patient is on a ventilator/bypassed airways, or when need more heat to break secretions.
8. What factors can shift the ISB deeper into the lungs/airways?
When a person breathes through their mouth, when they breathe cold dry air, when the upper airway is bypassed/artificial tracheal airway, or when minute ventilation is higher than normal the ISB is shifted DISTALLY.
What is gravimetric sedimentation?
When aerosol particles settle out of suspension and are deposited due to the pull of gravity. Breath-holding after inhalation increases sedimentation and distribution in the lungs. The greater the mass of a particle, the faster it settles.
What is Bernouli's principle?
When gas in a tube exerts lateral wall pressure due to the gas velocity.
When should HME be changed to a large volume nebulizer with a heater?
When secretions can't be broken up.
When does the ISB shift dismally?
When someone breathes dry cold air, airway is bypassed, or when the minute ventilation is higher than normal.
An asthmatic in severe distress is admitted to ER. After full assessment and obtaining a pre-treatment baseline, you start the patient on albuterol with an SVN. When should you stop documentation and the treatment?
When the patient's symptoms are relieved or when the PEFR/FEV1 in 1 second exceeds 70% of their personal best.
When are jet nebulizers used?
When there is a presence of upper airway edema, Laryngotracheobronchitis, subglottic edema, post-extubation edema, postoperative management of the upper airway, presence of a bypassed upper airway, or need for sputum specimens or mobilization of secretions.
37. When should an HME be used?
When upper airways are bypassed with mechanical ventilation.
Can bland aerosols cause bronchospasms in some patients?
Yes, yes they can.
if baby won't wear a mask for treatment what is used?
a blow-by technique, practitioner directs aerosol from nebulizer toward patients nose and mouth distance of several inches
Aerolizer and handihaler
dispense individual doses of drug from punctured gelatin capsules. Unit dose DPI
how frequently do you asses a CBT patient?
every 30 min for the first 2 hours, then hourly
Portion of inhaled mass that can reach lower airways is
respirable mass
Exhalation into the device before inspiration can result in what? I
t can result in the loss of drug delivery to the lungs.
How does a room humidifier work? I
t creates an aerosol that exits the device and evaporates in the ambient air increasing the humidity of the room.
What does the amplitude do to the ultrasonic nebulizer?
t directly affects the volume of aerosol output. You cannot change the frequency but you can increase the amplitude.