T2 Aerosol Drug Therapy Flashcards
What is aerosol ?
A suspended particle of a substance in a gas
Characteristics of therapeutic aerosol
Output
Particle size
Deposition
Aging
Factors affecting particle size
Substance being nebulizad
Nebulizar design
Aerosol generation method
Environmental conditions
MMAD
Mass median aerodynamic diameter
Upper AW recommended MMAD
5 to 50 um
Lower AW recommended MMAD
2 to 5 um
Parenchyma: alveolar region recommended MMAD
1-3 um
Parenchyma or exhaled recommended MMAD
<0.5 (<0.1) um
Deposition
The action of leaving the gas suspension
Emitted dose
The aerosol generated from the nebulizar
Inhaled dose
The part of the emitted dose that is inhaled
Inhaled mass
The actual amount of drug that is inhaled
Respirable mass
The proportion of the drug mass of proper size to reach lower AW
Key mechanisms of aerosol deposition are
Inertial impaction — large particles >5 um
Gravimetric sedimentation — deposition 1-5 um in central AW
Brownian diffusion— alveoli
Inertial impaction
Occurs when aerosol in motion collides with and are deposited on surface
Sedimentation
Occurs when aerosol particles settle out of suspension and are deposited due to gravity
Breath holding increases what ?
Sedimentation
Brownian diffusion
Primary deposition for particles <3 um in alveolar region
1-0.5 um are exhaled out
Aging
The process by which aerosol suspensions change over time
Factors affecting deposition
Inspiratory flow rate
Flow patterns
RR
VT
I:E ratio
Breath holding
AW obstruction and air- trapping
Indications SVN
Promote bronchial hygiene
Deliver medications
Induce sputum
Indications LVN
Humidify dry therapeutic gases
Presence of UAW edema
Post extubation edema
Bypassed UAWW
LTB / croup
promote bronchial hygiene
Induce sputum
Hazards of aerosol therapy
Infection
AW reactivity
Pulmonary / systemic effects
Drug concentrations
Eye irritation
Second hand exposure
Hazards of SVN
Bacterial contamination / infection
Bronchospasm
Drug reaction
Hazards of LVN
Bacterial contamination / infection
Bronchospasm
Tracheal burns
AW obstruction from swelling of inspissated secretions
Fluid overload / over hydration