HumidityAerosol Rx

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Humidity/Aerosol Rx
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Clearance of the Lungs

• Three mechanisms
• Mucociliary escalator
• Alveolar clearance
• Cough

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Mucus

• Composition
• Glycoproteins (mucin)
• Oligosaccharides (carbohydrate)
• Quality
• Elastic
• Viscous

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Mucus

• Coats
• Tracheobronchial tree epithelium
• Not beyond terminal bronchioles
• Produced by
• Goblet Cells
• Bronchial Glands

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Cilia

• Dimensions
• 0.2-0.3 microns in diameter
• 6 microns long
• Characteristics
• Beats 1300 times/minute
• Moves mucus at 1-2 cm/minute

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Mucokinesis

• Process of moving mucus
• Lungs cleared w/in 24 hours
• Cilia moves in sol layer and pushes gel layer
• Process affected by pulmonary insults

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Alveolar Clearance

• No mucus produced or cilia exist
• Macrophage engulf particulates
• Lysozyme (muramic acid) dissolve bacteria cell
  walls
• Dead macrophage is absorbed by lymphatic system

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Cough Mechanism

• Purpose
• To carry secretions to oropharynx to be
  expectorated or swallowed
• Terms
• High airflow velocity
• Shearing forces
• Turbulence

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Cough Mechanism

• Major defense system
• Vagal stimulation
• Retained secretions
• Thick mucus, e.g., dehydration
• Diseased lung, e.g., cystic fibrosis
• Poor ciliary action, e.g., chronic bronchitis

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Cough Mechanism

• 5 Components
• Deep breath in ? tidal volume
• Breath hold
• Glottic closure
• ? intrathoracic pressure Valsalvas
• Glottic opening and explusion peak flowrate of
  300 L/min

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Humidity v. Aerosol

• Humidity moistness, dampness, molecular water
• Aerosol solid or liquid particles suspended in a
  gas
• Mass median aerodynamic diameter (MMAD)
• ? 5? desirable for upper airway
• 5? desirable for lower airway
• Ideal 1-2?

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Humidity/Aerosol Rx

• Goals
• To improve bronchial hygiene
• To improve cough mechanism
• To improve mucociliary mechanism
• To humidify dry gases
• To deliver medications

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Indications

• Presence of upper airway edema
• Sputum induction
• ?airway resistance ? wheezing
• Retained secretions ? rhonchi
• Bypassed airways

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Contraindications

• Hyperreactive airways
• Cool or heated sterile water
• Bronchoconstriction
• Cool or heated sterile water
• Pulmonary edema

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Hazards/Complications

• Bronchospasm/bronchoconstriction
• Cross infection
• Overhydration
• Patient discomfort
• Health care worker exposure

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Assessment of Need

• Stridor
• Brassy cough, e.g., croup
• Sputum induction
• Adventitious breath sounds
• Wheezing
• Rhonchi

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Assessment of Outcome

• ?WOB
• Improved vital signs
• ? arterial blood gases
• Sputum obtained
• Improved patient comfort