Respiratory Care Pharmacology Chapter 3: Administration of Aerosolized Agents

list the 3 main uses of Aerosol Therapy

1. Humidification of dry inspired gases

2. Improved mobilization and clearance of respiratory secretions

3. Delivery of aerosolized drugs to the respiratory tract

the delivery of aerosol particles to the respiratory tract

Aerosol Therapy

suspension of fine liquid or solid particles in a carrier gas

aerosol

what is the aerosol particle size range of interest in pulmonary therapeutic application?

1-10 microns

what is the size range of aerosol particles in general?

0.001-100 microns

refers to the depth within the lung reached by the particles

penetration

True or False: Larger aerosol particles penetrate deeper into the airway

FALSE: the smaller the aerosol particles, the deeper they penetrate.

describes the process of the aerosol particles releasing from suspension to remain in the lung

Deposition

name 3 factors that influence particle deposition

-Particle size (the smaller, the more efficient)

-Anatomy of the airway

-Inspiratory Flow Rate and breathing patterns

what happens when a particle that is smaller than 1 micron in inhaled?

the particle remains in suspension (is not deposited) or is exhaled out

how do heat and humidity affect particle size?

increases particle size

True or False: Smaller particles penetrate deeper into the airway than larger particles

True: the smaller the particle, the deeper it penetrates

where in the respiratory tract would particles larger than 10 microns deposit?

-nasopharynx

-oropharynx

where in the respiratory tract would particles between 5-10 microns deposit?

the central airways

where in the respiratory tract would particles between 2-5 microns deposit?

overall lower respiratory tract

where in the respiratory tract would particles between 0.8-3 microns deposit?

deep into the lungs:

-terminal airways

-alveolar regions

encompasses various devices that operate on different physical principles to generate an aerosol from a drug solution

Nebulizer

means to convert a liquid into a fine spray, especially for inhalation of a medicinal drug

nebulize

aerosol generator that converts liquid drug solutions/suspensions into aerosol

Small Volume Nebulizer (SVN)

list the 3 types of small volume nebulizers

-Jet (pneumatic) Nebulizers

-Mesh Nebulizers

-Ultrasonic Nebulizers

how are jet nebulizers powered?

a gas source (air or oxygen)

list the 4 types of jet nebulizers

-Jet Neb w/ reservoir tube

-Jet Neb w/ collection bag

-Breath Enhanced Jet Neb

-Breath Actuated Jet Neb

this is the traditional, most common, least expensive jet nebulizer which delivers constant aerosol

Jet nebulizer with reservoir tube

what is the purpose of a Jet nebulizer's reservoir tube?

reducing the release of aerosol chemicals to ambient air (immediate surroundings)

True or False: The reservoir tube on a jet nebulizer completely eliminates ambient air contamination.

FALSE: the reservoir tube only reduces ambient air contamination but does not eliminate it.

this feature on a specific jet nebulizer prevents loss of aerosol because of the one-way inspiratory valve between the nebulizer and mouthpiece

collection bag

what is the difference between Breath-Enhanced and Breath-Actuated jet nebulizers?

-Breath-Enhanced Jet Nebs: aerosol release is increased by inspiration, and decreased by expiration.

-Breath-Actuated Jet

Nebs: aerosol is released ONLY during inspiration, and STOPS upon exhalation.

which Jet Nebulizer feature reduces ambient contamination more?: Collection bag or Reservoir tube?

Collection Bag

term for the amount of drug solution remaining in the reservoir cup when the nebulizer begins to sputter and aerosolization ceases

Dead Volume (Residual Volume)

Jet nebulizers will not aerosolize below a minimum volume; this volume is termed...

Dead Volume (Residual Volume)

what is the minimum volume required for jet nebulizers to deliver a drug?

3-5 mL

what is the general range of nebulizer dead volumes?

0.5-1 mL

how do we increase solution filling volume in jet nebulizers to avoid dead volume?

diluting the medication solution with normal saline solution

does adding diluent alter the drug dose?

NO: adding diluent simply "expands" the solution; does not affect the drug dose.

how does the filling volume in Jet Nebs affect the treatment time?

the more fill volume, the longer the treatment time

how does the flow rate of the gas source affect Jet Neb treatment time?

increased flow rate = shorter treatment time

name the 2 types of power gas for Jet Nebulizers

-oxygen

-air

name the 2 types of Jet Neb device interfaces (user attachments)

-Mouthpiece

-Facemask

how does solution viscosity affect Jet Neb Treatment time?

the more viscous, the longer the treatment time

what is the optimal flow rate for Jet Nebulizers containing aqueous solutions?

8-10 L/min

what is the optimal flow rate for Jet Nebulizers containing viscous solutions?

10-12 L/min

how does gas flow rate affect particle size of aerosols?

higher flow rates produce smaller sized aerosol particles (better deposition)

why is the mouthpiece recommended over face masks on Jet Nebulizers?

the mouthpiece provides greater lung deposition, as face masks tend to deposit some aerosol on the face and eyes

Can Jet Nebulizer mouth pieces be used on infants and small children? Why or why not?

NO; infants are obligate nose breathers.

during aerosol therapy, should patients be instructed to inhale through the nose, or the mouth? why?

The mouth; the nose tends to filter more aerosol, which decreases lung deposition.

this small volume nebulizer uses a plate with 1000-4000 holes that vibrate to create aerosol.

Mesh Nebulizer

how are Mesh Nebulizers powered

Electrically powered (plug in or batteries)

do mesh nebulizers require a gas source?

NO; Mesh Nebulizers are electrically powered.

name a specific Mesh Nebulizer used in practice

Aerogen

Small Volume Nebulizer that operates on piezoelectric principle and is capable of high output

Ultrasonic Nebulizer

what does "SPAG" stand for?

Small Particle Aerosol Generator

for what 2 reasons do we not use Ultrasonic Nebulizers often?

-The heat produced tends to denature medicinal proteins (inactivates the drug)

-Expensive and fragile

what is the SPAG Unit used for?

Ribavirin antiviral drug used to treat RSV

what is the Respiguard II Jet Nebulizer used for

Pentamidine for patients with PCP

small pressurized canisters for oral or nasal inhalation aerosol drugs

Pressurized Meter Dose Inhalers (pMDI/MDI)

name the 3 categories of pMDIs

-Conventional pMDI

-Breath-actuated pMDI (off-market)

-Soft Mist Inhaler

name the 5 components of a pMDI

-canister

-propellant

-drug formulary

-actuator

-metering valve/dose counter

why were CFC drugs banned by the FDA? What were they replaced by?

CFCs are dangerous to the environment; Replaced by HFA drugs

what is the main benefit of using a spacer with pMDIs?

spacers reduce aerosol particle size, which increases lung deposition.

what kind of inhalation technique should be used with pMDIs?

Slow, deep, breath; hold for 10 seconds

name 3 different synonyms for "MDI Spacer"

-Valved Holding Chamber

-Extension Device

-MDI Reservoir

pMDI that produces a very fine spray

Soft Mist Inhaler

name a specific Soft-Mist Inhaler

RESPIMAT

breath actuated inhaler that delivers drugs in a powdered form

Dry Powder Inhaler (DPI)

what is the breathing technique required for DPIs?

Fast, deep breath; hold for 10 secs

what is the main disadvantage of DPIs?

it requires a high inspiratory flow rate from the patient in order for the drug to be dispensed.

what is the inspiratory flow rate required by the DPI?

30-90 L/min

what patients should use a spacer with pMDIs?

All patients!

True or False: the amount of bronchodilation is determined by the device used, not the dose of the drug.

FALSE: the amount of bronchodilation is a reflection of the drug dose, not the method of delivery.

what ages can use a SVN?

all ages

what ages can use an MDI?

older than 5 years

what ages can use a DPI?

older than 5 years