Aerosol Drug Therapy Flashcards
(42 cards)
What is an Aerosol?
suspension of solid or liquid particles in gas generated with devises that physically disperse matter into small particles and suspend them into gas
What is the goal of Aerosol therapy?
Deliver a therapeutic dose of the selected pharmacological agent to the desire site of action
Particle sizes
measured by particle suspension in a lab
Heterodisperse
Aerosols with different particle sizes (most common)
Monodisperse
Aerosols with particles of similar size
Particle size depends on…
substance, method used to generate, environment
Inhaled Mass
Only fraction of emitted aerosols will be inhaled
Respirable Mass
Only fraction of inhaled is deposited into the lungs
MMAD
mass median aerodynamic diameter which is a method to measure aerosols
What influences particle mass
inspiratory flow rate, flow pattern, respiratory rate, inhaled volume, I:E ratio, breath-holding
Types of aerosols
atomizes, nebulizers, inhalers
Adding medication to aerosols
provides higher therapeutic index
Types of deposition
inertial impaction, sedimentation, brownian diffusion
Inertial Impaction
particle size >5 - impacts upper airway; nose, larynx, and trachea - mainly oropharynx
Sedementation
particle size 1-5 - central airways (2-5 lower airways) (1-3 parenchyma, alveolar region)
Breath Holding
after inhalation of aerosol increases sedimentation and distribution across lungs
Brownian
particle size <3 - parenchyma (respiratory region)
particle size between 0.5 and 1
very low mass and can be exhaled back out
particle sizes <0.5
greater lung retention rate
Hazard of aerosol therapy
adverse reaction to medication, airway reactivity leading to bronchospasm
Types of aerosol therapy
MDI, DPI, pneumatic nebulizers, large volume nebulizers
MDI (pressurized Metered Dose Inhaler)
portable, compact, easy to use, most commonly prescribed, rescue inhaler, drug = HFA (hydrofluoroalkane)
Priming
shaking device and releasing one or more sprays into air when pMDI is new or hasn’t been used in awhile
pMDI particle size
2-6 (about 80% deposits in oropharynx and 10-20% is deposited pulmonary)