Bland Aerosol Therapy

Bland Aerosol Therapy

• Bland aerosol consists of liquid particles suspended in a gas, either oxygen or air.
• Liquids used can be sterile water, sterile saline (hypotonic, isotonic or hypertonic)

Indications for Bland Aerosol Therapy

• Can be used for the presence of upper airway edema, such as when using a cool bland aerosol.
• Can be used if there is laryngotracheobronchitis.
• Can be used for subglottic edema.
• Can be used for postextubation edema.
• Useful for the postoperative management of the upper airway.
• Use when there is a bypassed upper airway.
• Assists with the need for sputum specimens or mobilization of secretions.

Contraindications

• Do not use if there is bronchoconstriction.
• Do not use if there is a history of airway hyperresponsiveness.
• Can result in wheezing or bronchospasm.
• Can lead to infection.
• Risk of overhydration.
• May cause patient discomfort.
• Poses a risk of caregiver exposure to airborne contagions during coughing or sputum induction.
• Can cause edema of the airway wall.

Large-Volume Jet Nebulizers

• This is the most common device for bland aerosol therapy.
• Pneumatically powered, connecting directly to a flowmeter and compressed gas source.
• Unheated nebulizers: Produce 26-35 mg H20/L.
• Heated nebulizers: Produce 35-55 mg H20/L, mainly from increased vapor capacity.
• A variable air-entrainment port allows air mixing, to increase flow rates and alter FiO2 levels.

Mechanism of Action for Large-Volume Jet Nebulizers

• Gas flow generates liquid particles at high velocity, through a small jet orifice.
• Low pressure draws fluid from a reservoir up a siphon tube.
• Water is then shattered into liquid particles.
• Smaller particles exit the nebulizer through the outlet port in a gas stream.

Ultrasonic Nebulizer

• It is an electrically powered device using a piezoelectric crystal to generate aerosol.
• A crystal transducer converts radio waves into high-frequency mechanical vibrations that produce aerosol.
• Particle size is inversely proportional to signal frequency.
• Signal amplitude directly affects aerosol output volume.
• Flow and amplitude settings interact to determine aerosol density (mg/L) and total water output (ml/min).

Rules of Thumb

• USN is used with sputum induction
• Set amplitude high and flow rate low.
• Doing so produces a high-density aerosol useful for sputum induction.
• Aerosol delivery should be maximized per minute when mobilizing secretions.
• High cost and erratic reliability.

Airway Appliances

• Types include: Aerosol mask, Face tent, T-tube, and Tracheostomy mask
• Use large-bore tubing to minimize flow resistance, and prevent occlusion by condensate.

Enclosures

• These include Mist Tents and Hoods
• Aerosol hoods can provide similar aerosol delivery efficiency to a fitted aerosol mask in infants.
• Used for aerosol therapy in infants and children.
• Heat retention and CO2 buildup in tents can pose a problem.
• Employ high flows of fresh gas circulating continually through the tent to help "wash out" CO2 and reduce heat buildup.

Sputum Induction

• It is a useful, cost-effective, and safe method for diagnosing tuberculosis (TB), pneumosystis pneumonia (P. jiroveci), and lung cancer
• It involves short-term application of high-density hypertonic saline (3-10%) aerosols to the airway.
• Observe sputum for volume, color, and consistency; also note odor and presence of blood.
• Examples of sputum descriptions: Large, thick, and tan OR Small, thin, and clear

Problem Solving and Troubleshooting

• Potential cross-contamination and infection.
  • Adhere to infection control guidelines.
• Potential environmental exposure.
  • Follow CDC standards and airborne precautions.
  • Occupational asthma.
• Inadequate mist production.
  • Inadequate driving gas flow.
  • Siphon tube obstruction.
  • Jet orifice misalignment.
• Overhydration.
  • Prevention is key through patient selection and monitoring.
• Bronchospasm.
  • Treatment should be stopped immediately, provide oxygen.
• Noise.

Key Considerations for Conditioning Inspired Gas

• Gas flow
• Presence/absence of an artificial tracheal airway
• Character of pulmonary secretions
• Need for and expected duration of MV
• Contraindications to using an HME