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Aerosol Therapy Overview
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Aerosol Therapy Overview
Aerosol Therapy Overview
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1
Question
What is an aerosol?
Answer
An aerosol is a suspension of solid or liquid particles in gas, found naturally as pollen, dust, or mist. In medicine, aerosols from atomizers, nebulizers, or inhalers deliver solutions or drugs to the respiratory tract for local or systemic effects.
2
Question
What does aerosol output refer to?
Answer
Aerosol output refers to the mass of fluid or drug produced by an aerosol generator. It describes the mass of drug or liquid emitted from the generator, with the output rate being the mass of aerosol generated per unit of time.
3
Question
How can aerosol output be measured?
Answer
Measurement of aerosol output can be done by collecting the aerosol that leaves the nebulizer on filters and measuring either their weight (gravimetric analysis) or drug quantity (assay). Gravimetric analysis is easier but less reliable due to water evaporation effects, while a drug assay provides a more reliable measure.
4
Question
What factors influence the travel, entry, and deposition of aerosols in the lungs?
Answer
Factors influencing the travel, entry, and deposition of aerosols include particle size and breathing pattern.
5
Question
What is the significance of particle size in aerosol delivery?
Answer
Particle size is influenced by the substance for nebulization, the aerosol generation method, and the environment. Human eyes cannot see particles smaller than 50-100 m.
6
Question
What are cascade impactors used for?
Answer
Cascade impactors collect aerosols of different size ranges on a series of stages/plates to measure mass distribution by drug assay, resulting in mass median aerodynamic diameter (MMAD).
7
Question
What is laser diffraction?
Answer
Laser diffraction uses a computer to estimate the range and frequency of droplet volumes crossing the laser beam, resulting in volume median diameter (VMD).
8
Question
What does MMAD stand for?
Answer
MMAD stands for mass median aerodynamic diameter, which describes average particle sizes in micrometers (µm).
9
Question
What does GSD represent in aerosol delivery?
Answer
Geometric standard deviation (GSD) shows size variability of aerosol particles. A higher GSD indicates a more heterodisperse aerosol, while a GSD of 1.2 indicates a monodisperse aerosol, mainly used in research or non-medical industries.
10
Question
What is the inhaled dose?
Answer
The inhaled dose is the portion of the aerosol that is inhaled by the user.
11
Question
What is the respirable dose?
Answer
The respirable dose is the fraction of aerosol particles that reach the lungs.
12
Question
What are the deposition mechanisms in aerosol therapy?
Answer
Deposition mechanisms include inertial impaction, sedimentation, and Brownian diffusion.
13
Question
What is inertial impaction?
Answer
Inertial impaction refers to particles larger than 5 µm colliding with surfaces due to mass and velocity, commonly occurring with turbulent airflow or obstructed pathways.
14
Question
What is Brownian diffusion?
Answer
Brownian diffusion is the mechanism by which small particles (1-3 µm) reach the alveoli by diffusion, independent of flow or gravity.
15
Question
What is aerosol aging?
Answer
Aging refers to the change over time of aerosol particles due to growth, shrinkage, coalescence, or falling out of suspension, influenced by composition, initial size, suspension time, and ambient conditions.
16
Question
What are the hazards of aerosol therapy?
Answer
Hazards of aerosol therapy include adverse reactions to medication, infection, airway reactivity, systemic effects of bland aerosols, drug concentration issues, eye irritation, and secondhand exposure.
17
Question
What is the primary hazard of aerosol therapy?
Answer
The primary hazard is an adverse reaction to the medication being administered.
18
Question
What can cause infection in aerosol therapy?
Answer
Aerosol generators can spread nosocomial infections from patient secretions, contaminated solutions, or caregivers' hands, with common pathogens including Gram-negative bacilli like Pseudomonas aeruginosa.
19
Question
How can airway reactivity be triggered during aerosol therapy?
Answer
Cold air and high-density aerosols can cause bronchospasm and increased airway resistance, particularly in patients with respiratory diseases.
20
Question
What are the precautions to take to prevent infection during aerosol therapy?
Answer
Nebulizers should be sterilized between patients, frequently replaced with disinfected or sterile units, or rinsed with sterile water.
21
Question
What are the factors contributing to eye irritation during aerosol delivery?
Answer
Aerosol delivery via face masks may deposit drug in the eyes, causing irritation, with certain anticholinergic drugs suspected to worsen glaucoma.
22
Question
What is the LT ratio in aerosol therapy?
Answer
The LT ratio measures how efficiently the aerosol delivers to the lung, where a higher ratio indicates better lung availability and lower gastrointestinal availability.
23
Question
What inhalation pattern is recommended for effective aerosol delivery?
Answer
A slow inspiration of 5-6 seconds with a 10-second breath-hold improves drug sedimentation and diffusion.
24
Question
What are pressurized metered dose inhalers (pMDIs)?
Answer
pMDIs are portable, compact inhalers that provide multidose convenience, dispensing a uniform dose of drug after actuation.
25
Question
What is the role of dispersal agents in pMDIs?
Answer
Dispersal agents like surfactants keep the drug suspended but can cause adverse effects such as coughing or wheezing.
26
Question
What is the importance of priming a pMDI?
Answer
Priming a pMDI by shaking and actuating it 1-4 times is essential to ensure the correct initial dose; otherwise, the first dose may contain less active drug.
27
Question
What are dry powder inhalers (DPIs)?
Answer
DPIs are inhalers where patients create aerosol by inhaling air through a finely milled drug powder, allowing for drug delivery without the need for propellants.
28
Question
What factors affect DPI performance?
Answer
DPI performance is affected by intrinsic resistance, inspiratory flow rate, and exposure to humidity and moisture.
29
Question
What materials are commonly used for accessory devices in aerosol therapy?
Answer
Accessory devices can be made of conductive metal or nonelectrostatic plastic chambers, with periodic washing of plastic chambers recommended to reduce fine-particle loss.
30
Question
What is the significance of inspiratory flow rate when using DPIs?
Answer
Optimal performance for each DPI design occurs at a specific inspiratory flow rate, typically requiring high peak inspiratory flows of 60 L/min.