I did some refreshing on the types of inhalers as well as common problems and advantages of each type of inhaler
Metered
Dose Inhaler
·
First introduced
in 1956
·
Developed with a
small particle size (<5 microns) and able to get to lower airways with
minimal systemic effects
o
Lung distribution
of 50-60% in new HFA formulation
·
Medication is
contained in a liquefied compressed gas that maintains a certain pressure.
·
Used to use CDC
propellants, now use HFA propellants
o
New HFA propellant
is more polar which has limited solubility with a lot of compounds
·
Only two drugs
with MDI HFA formulations: albuterol and beclomethasone dipropionate
·
Two types of MDI
o
Breath-actuated
inhalers- automatically release a spray of medication with an inhalation (pirbuterol)
o
Press and breathe
inhalers- requires push of button to release medication (albuterol)
·
Common errors in
the press and breathe MDI
o
Forget to remove
the cap or shake the inhaler
o
Use the inhaler
upside down
o
Press down before
inhalation
o
Press down after
inhalation complete
o
Don’t hold breath
after inhalation
Dry
Powder Inhaler
·
Does not contain a
propellant, all are currently breath-actuated
·
Requires force of
inhalation to get medication into the lungs
o
Problematic
especially during asthma attacks or with young children
·
Must inhale all medication
in one or two breathes and can be difficult to judge
·
Over 17 varieties
o
Single-dose
models- load capsule into the reservoir and inhale the dose
o
Multi-dose model-
have a reservoir of powder which needs to held upright before loading a dose
for inhalation
·
Common errors of
inhalers
o
Failure to remove
cover
o
Incorrect dose
loading
o
Failure to pierce
capsule
o
Breathing out of
device
o
Blocking
inhalation vents
o
Poor seal around
the mouthpiece
o
Not inhaling with
enough speed or velocity
o
Inhaling through
the nose
Respimat
Soft Mist Inhaler
·
Use liquid
formulation like a nebulizer but in a multi-dose device
·
Inhaler is powered
via compressed spring and there is no propellant in the inhaler
·
Lower spray
velocity and long duration versus MDI
o
Higher lung
deposition
o
Lower doses
without decreasing efficacy
·
Contains higher
fraction of fine particle than most MDIs or DPIs
·
Common errors
o
Failure to prime
or load dose
o
No exhalation
o
Inhalation issues:
firing device before inhalation, firing device after inhalation, discontinuing
inhalation early, inhaling too quickly
o
Don’t hold breath
o
Block vents with
mouthpiece
Nebulizer
·
Electric or
battery powered machine that turns liquid medication into a mist
·
Allows for various
medications to be administered: anticholinergics, antibiotics, and mucolytics
are some examples
·
Don’t require
coordination of breaths and release of medication
·
Disadvantages:
o
Large devices
o
Treatments take a
long time (can be about 15 minutes)
o
Requires extensive
cleaning to prevent an infection
o
Requires a power
source
o
Typically not
portable
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