Aerosol Therapy and Nebulizers

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Aerosol Therapy and Nebulizers

• RET 2274
• Respiratory Therapy Theory
• Module 6.2

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Aerosol Therapy and Nebulizers

• Aerosols
• Particulate matter suspended in a gas
• Aerosols occur in nature as pollens, spores,
  dust, smoke, smog, fog, and mist
• In the clinical setting, medical aerosols are
  generated with atomizers, nebulizers, and
  inhalers physical devices that disperse matter
  into small particles and suspend them into a gas

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Aerosol Therapy and Nebulizers

• Aerosols
• Medical aerosols are intended to deliver a
  therapeutic dose of the selected agent to the
  desired sit of action, e.g., bronchioles

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Aerosol Therapy and Nebulizers

• Aerosols
• Deposition
• Only a portion of the aerosol generated from a
  nebulizer (emitted dose) man be inhaled (inhaled
  dose) a smaller fraction of fine particles may
  be deposited in the lung (respirable dose)
• Not all aerosol delivered to the lung is
  retained, or deposited a significant percentage
  of inhaled drug may be exhaled

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Aerosol Therapy and Nebulizers

• Aerosols
• Deposition
• Inertial Impaction the primary deposition
  mechanism for particles larger than 5 µm
• Tend to be deposited in the oropharynx and
  hypopharynx

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Aerosol Therapy and Nebulizers

• Aerosols
• Deposition
• Sedimentation the primary mechanism for
  deposition of particles in the 1 5 µm range
• The greater the mass of a particle, the faster it
  settles
• Tend to be deposited in the central airways
• Breath holding after inhalation of an aerosol
  increases enhances sedimentation

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Aerosol Therapy and Nebulizers

• Aerosols
• Deposition
• Brownian Diffusion is the primary mechanism for
  deposition of small particles lt3 µm bulk gas
  flow ceases and aerosol particles reach the
  alveoli by diffusion
• Particle size is not the only determinant of
  deposition
• Inspiratory flow rate, flow pattern, respiratory
  rate, inhaled volume, IE ration, and
  breath-holding all influence deposition

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Aerosol Therapy and Nebulizers

• Aerosols
• Quantification of Aerosol Delivery
• At the bedside, quantification of aerosol
  delivery is based on the patients clinical
  response to the drug
• Pulmonary function peak flow, forced expiratory
  volumes or flow
• Physical changes reduced wheezing, shortness of
  breath, or retractions
• Side effects tremors, tachycardia

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Aerosol Therapy and Nebulizers

• Aerosols
• Hazards
• Adverse reaction to the medication being
  delivered
• Infection caused by contaminated solution
  (multi-dose vials), caregivers hands, the
  patients own secretions

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Aerosol Therapy and Nebulizers

• Aerosols
• Hazards
• Airway reactivity
• Cold and high-density aerosols can cause
  bronchospasm and increased airway resistance
• Medications, e.g., acetylcysteine, antibiotics,
  steroids, cromolyn sodium, ribavirin, and
  distilled water have been associated with
  increased airway resistance and wheezing during
  aerosol therapy
• Administration of bronchodilators before or with
  administration of these agents may reduce the
  risk of increased airway resistance

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Aerosol Therapy and Nebulizers

• Aerosols
• Hazards
• Pulmonary and Systemic Effects
• Overhydration from excessive water
• Hypernatremia from excess saline solution
• Drug Reconcentration
• During evaporation, heating, baffling, and
  recycling of drug solutions undergoing jet or
  ultrasonic nebulization, solute concentrations
  may increase exposing patients to increasingly
  higher concentrations of drug therapy. Increase
  in concentration usually time dependent, the
  greatest effect occurring when medications are
  nebulized over extended periods, as in continuous
  aerosol drug delivery

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Aerosol Therapy and Nebulizers

• Aerosols
• Delivery Systems
• MDI Metered Dose Inhalers
• DPI Dry Powder Inhalers
• Pneumatic (Jet) Nebulizers
• Large volume
• Small volume
• Ultrasonic Nebulizers
• Large volume
• Small volume
• Hand-Bulb Atomizers

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Aerosol Therapy and Nebulizers

• Aerosols
• Indications AARC Clinical Practice Guideline
• The need to deliver an aerosolized
  beta-adrenergic, anticholinergic,
  antiinflammatory, or mucokinetic agent to the
  lower airway

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Aerosol Therapy and Nebulizers

• Aerosols
• Selection of Aerosol Delivery Device
• MDI preferred method for maintenance delivery
  of bronchodilators and steroids to spontaneously
  breathing patient effectiveness is highly
  technique dependent
• Accessory devices e.g., spacer and holding
  chambers are used with MDI to reduce
  oropharyngeal deposition of drug and overcome
  problems with poor hand-breath coordinaiton

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Aerosol Therapy and Nebulizers

• Aerosols
• Selection of Aerosol Delivery Device
• DPI does not require hand-breath coordination,
  but does require high inspiratory flows
• Most patients in stable condition prefer DPI
  delivery systems
• SVN less technique and device dependent and are
  the most useful in acute care

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Aerosol Therapy and Nebulizers

• Aerosols
• Selection of Aerosol Delivery Device
• Large volume drug nebulizers provide continuous
  aerosol delivery when traditional dosing
  strategies are ineffective in controlling severe
  bronchospasm
• Small Volume USN used to administer
  bronchodilators, antiinflammatory agents, and
  antibiotics

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Aerosol Therapy and Nebulizers

• Aerosols
• Patient Assessment
• Patient interview
• Respiratory history
• Level of dyspnea
• Observation
• Signs of increased work of breathing
• Tachypnea, accessory muscle usage
• Restlessness
• Diaphoresis
• Tachycardia

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Aerosol Therapy and Nebulizers

• Aerosols
• Patient Assessment
• Expiratory airflow measurements
• FVC, FEV1, PEFR
• Vital signs
• Auscultation of breath sounds
• Increase or decrease in wheezing and intensity of
  sounds
• Blood gas analysis
• Oximetry