3d. Pneumatic (Jet) Nebulizer Flashcards
What are most nebulizers powered by?
•High-pressure oxygen or air provided by portable compressor •Compressed gas cylinder •50-psi wall outlet to aerosolize liquid medication
What patients often use Pneumatic (Jet) Nebulizer?
•Infants •Patients with ARDS •Patients who have slow breathing and may not obtain an inspiratory pause
What’s a Baffle and what’s its purpose?
A surface in which large particle impact and fall out of suspension, and produce small particles ‣ Decreases MMAD (size) and GSD (range of sizes)
What’s a Capillary Tube?
Where the liquid flows up the tube
What’s a Jet and what’s its purpose?
…
How does a Pneumatic (Jet) Nebulizer generate aerosol?
‣ External source of compressed gas goes through a narrow orifice inside the reservoir cup ‣ Creates a localized negative pressure and draws drug solution up capillary/feeder tubes ‣ When liquid enters the gas stream, droplets form from gas turbulence and impaction from baffles ‣ Smaller particles size emitted after baffling process, and larger particles recirculated back to reservoir
What causes Drug Reconcentration, and how much does the concentration increase from the original solution?
‣Evaporation and constant recirculation, drug becomes increasingly concentrated 150-300%
What are the factors affecting Nebulizer Performance? (5)
‣Nebulizer Design ‣Gas Pressure and Flow ‣Gas Density ‣Medication Characteristics ‣Humidity and Temperature
How does Gas Pressure and Flow affect Nebulizer perfomance?
‣ Affects particle size distribution and output ‣ The Greater Pressure and Flow ➔ the smaller the particle size, greater output, and shorter treatment time
What’s the relationship between Gas Flow to the Droplet Size and Nebulization time?
‣ Inversely proportional The higher flow of gas to nebulizer ➔ the smaller particles and shorter time required for nebulization
How does Gas Density affect Nebulization performance?
‣ Affects aerosol generation and delivery to the lungs The lower the Density ➔ less aerosol impaction as gas passes through airways, and greater deposition
How does Humidity and Temperature affect Nebulization performance?
‣ Affects particle size and concentration of drug remaining in the nebulizer ‣ Aerosol particle entrained into a warm and fully saturated gas stream increases in size ‣ Reduction of temperature from evaporation to 10 C less than ambient may increase solution viscosity, and reduce nebulizer output while decreasing particle MMAD
What’s the range size of aerosol droplets when its dispersed?
0.1-500 um
What are 4 types of Small Volume Nebulizers?
◦ Small Volume Nebulizer with Simple Reservoir ◦ Continuous Nebulizer with Collection Reservoir Bag ◦ Breathe Enhanced ◦ Breath Actuated Nebulizer (BAN)
Small Volume Nebulizer with Simple Reservoir: How much can the inhaled dose be increased?
‣ May increase inhaled dose by 5-10%, or from 10 to 11% with 6-inch piece of reservoir tube
Continuous Nebulizer with Collection Reservoir Bag: What’s the bag for?
‣ Bag reservoirs hold aerosol generated during exhalation ‣ Allows small particles to remain in suspension for inhalation with next breath while larger particles rain out ‣ Inhaled aerosol in the bag ➔ increases total dose efficiency
Continuous Nebulizer with Collection Reservoir Bag: How much can the inhaled dose be increased?
‣ Attributed to 30-50% increase in inhaled dose
Continuous Nebulizer with Collection Reservoir Bag: How does it work?
• Patient inhales aerosol from the reservoir through a one way valve and exhales to the atmosphere through an exhalation port between valve and mouthpiece
Breath Enhanced: How does it work?
• Air from the compressor breaks the liquid medication into small breathable particles which form a mist (aerosol). • As the patient breathes in, the valve at the top opens, letting air in and speeding up the mist generation. • When the patient breathes out, the top valve closes, slowing down the mist and the mouth piece flap opens letting the patient’s breath out.
Breath Enhanced: What’s the one way valves for?
To prevent the medication from escaping until the patient takes another breath
Breath Actuated Nebulizer: What is it designed to do?
‣ Designed to increase aerosol drug delivery by generating aerosol only during active inspiration
Breath Actuated Nebulizer: How much can the inhaled dose be increased?
‣ Can increase inhaled aerosol mass by 3-4 fold over conventional continuous nebulization
What are two types of Breath Actuated Nebulizers?
Manual Breath-Actuated and Mechanical Breath-Actuated
Manual Breath Actuated Nebulizer: How does it work?
• Uses thumb to control and regulate aerosol production during insp. and exp. • Blocking the thumb port directs gas to the nebulizer only during inspiration. Releasing thumb pauses the nebulization
Manual Breath Actuated Nebulizer: What’s an advantage and disadvantage?
Advantage: Less wasted medication Disadvantage: Increases treatment time and required hand-breath coordination
Mechanical Breath-Actuated: How does it work and whats a Brand for it?
AeroEclipse • Breath-actuated valve that triggers aerosol generation only during active inspiration
Mechanical Breath-Actuated: What’s an advantage and disadvantage/limitation?
Advantage: Eliminates need for storage bag or reservoir Limitation: Patient must be able to generate sufficient inspiratory flow to trigger nebulizer
What’s the main technique to optimize SVN aerosol deposition?
Slow inspiratory flow
What are delivery methods for SVNs?
Mask or Mouthpiece. Encourage mouthpiece unless they are not able to have a good seal in their mouth
What’s the Technique Step by Step to use an SVN?
• Assess the patient for need (clinical signs and symptoms, breath sounds, peak flow, %FEV1). • Select mask or mouthpiece delivery (nose clips may be needed with mouthpiece). • Use conserving system (thumb port, breath actuator or reservoir) if indicated. • Place drug in the nebulizer. If using a multidose vial, add saline to approved dose volume (per drug label). • Set gas flow to nebulizer at 6 to 10 L/min (per manufacturer label). • Coach patient to breathe slowly through the mouth at normal VT. • Continue treatment until nebulizer begins to sputter. • Rinse the nebulizer with sterile water and air dry, or discard, between treatments. • Monitor patient for adverse response. • Assess outcome (change in peak flow, %FEV1). hO
What can happen when you fail to clean an SVN?
‣ Failure to clean ➔ degradation of performance ➔ clogging of jet orifice, reducing output flow, and buildup of electrostatic change in the device
Advantages of SVNs (5)
‣ Less patient coordination required
‣ High doses possible (even continuous)
‣ Effective with low inspiratory flows or volumes
‣ Normal breathing pattern can be used
‣ Drug concentrations and dose can be modified if desired
Disadvantages of SVNs (6)
‣ Wasteful ‣ Drug preparation required ‣ Contamination possible ‣ Pressurized gas source required ‣ Long treatment times ‣ Not all medications available
Large Jet Nebulizers: What is it used for (compared to SVNs)?
◦ Used to delivery aerosolized drugs to lungs or deliver bland aerosol ◦ Patients who need continuous bronchodilators several hours without having to refill every 15 min. ◦ And when SVNs aren’t affective
What are 4 types of Large Jet Nebulizers?
‣ HEART ‣ Westmed ‣ HOPE ‣ Small-particle aerosol generator (SPAG)
Small-Particle Aerosol Generator: What medication is used and for what disease?
• Medication: Ribavirin (Virazole) ➔ Disease: RSV
Small-Particle Aerosol Generator: Precautions to take when administering
• Administer SPAG in negative pressure room and use PPE, due to environmental contamination
Small-Particle Aerosol Generator: What’s the Drying Chamber for?
It’s to dehydrate the large particles and decrease the MMAD of particles
What’s Sputtering and where does is begin around?
Sputter is a noise when the nebulizer stopped with the onset of inconsistent nebulization. That’s when it’s best to end the treatment. It begins to sputter when there’s 2.5 mL volume remaining
Large Jet Nebulizers: What’s the MMAD particle size?
1.2-1.4 um
