INSPIRATION! Aerosol Delivery 101

The following was published in the April 2006 Respiratory supplement "Inspiration!"

For people living with COPD, asthma or Cystic Fibrosis, the delivery of aerosol medication can dramatically improve breathing. Currently there are one million diagnosed cases of chronic obstructive pulmonary disease (COPD) in the United States, while asthma afflicts about 20 million Americans and is the most common chronic illness among children, accounting for $11.5 billion in direct health care costs annually. Cystic fibrosis (CF) although relatively rare, affects 30,000 people in the United States. It is an inherited disease that affects the lungs and digestive system and is chronic, progressive and ultimately fatal.

Types of Aerosol Delivery Devices
Metered-Dose Inhalers (MDIs) are currently used for a variety of diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and other lung diseases characterized by obstruction of airflow and shortness of breath. Metered-dose inhaler products contain therapeutically active ingredients dissolved or suspended in a propellant, a mixture of propellants, or a mixture of solvents, propellants, and/or other recipients in compact pressurized aerosol dispensers. An MDI product may discharge up to several hundred metered doses of one or more drug substances. MDIs have unique differences with respect to formulation, container, closure, manufacturing, in-process and final controls, and stability. These differences need to be considered during the development program because they can affect the ability of the product to deliver reproducible doses to patients over the life of the product as well as the product's efficacy.

  • Small, easy to clean.
  • Efficacy is design and technique dependent.
  • Inexpensive, convenient, portable and no drug preparation required.
  • May be used in-line with ventilators.
  • Patient self-administered, may not be appropriate for pediatric or geriatric patients.
  • Requires hand-breath coordination, synchronization with inspiration and a 4-10 second breath hold.
  • Spacer or holding chamber is recommended, especially with children.

Nebulizers are compressed air machines that turns liquid asthma medicine into a fine mist patients can easily breathe. Nebulizers are good for young children, people who have trouble using metered dose inhalers, and people who have severe asthma. Nebulizers come in many forms. Nebulized medication that is released into the atmosphere from the nebulizer or exhaled by the patient becomes a form of secondhand exposure that may affect health care providers or other people in the vicinity of treatment. There are both small volume nebulizers and large volume nebulizers. Small volume are also called handheld, mini-neb, sidestream, slipstream, mainstream or in-line and are used to deliver intermittent aerosolized medications and short-term use only. Large volume nebulizers are used for continuous oxygen and / or aerosol (heated or cool).

Ultrasonic (USN) is used to mobilize thick secretions in the lower airways. Typically USNs are only used intermittently but may be used for continuous therapy.

Dry Powder Inhaler (DPI) provides intermittent delivery of a powdered medication.

  • Breath actuated and patient self-administered
  • Breath holding not required
  • High humidity may affect some drugs
  • Many drugs are unavailable in DPI form
  • Not recommended for patients < six="" years="" or="" with="" acute="" bronchospasm.="" some="" products="" require="" high="" flow="" rates="" and="" may="" not="" be="" appropriate="" for="" pediatric="" or="" geriatric="" patients.="">

Hazards of Aerosol Therapy

  • Adverse reaction to medication; rashes in health care workers exposed to secondhand aerosols
  • Airway obstruction
  • Airway thermal injury
  • Caregiver exposure to airborne contagion
  • Bronchospasm
  • Drug reconcentration
  • Infection
  • Overhydration
  • Overmobilization
  • Systemic Effects
  • Conjunctivitis
  • Decreased tolerance to contact lenses
  • Headaches
  • Shortness of breath

CDC recommends that exposure to aerosols is controlled by:

  • Administrative policy
  • Engineering controls
  • Personal protective equipment

Device Selection
Evidence-based guidelines for the appropriate selection of aerosol delivery devices are needed.

When selecting an aerosol delivery device for patients with asthma and COPD, the following factors should be considered:

  • Device/drug availability
  • Clinical setting
  • Patient age and the ability to use the selected device correctly, cognitive ability
  • Device use with multiple medications
  • Cost and reimbursement
  • Drug administration time
  • Convenience in both outpatient and inpatient settings
  • Physician and patient preference

Usage Tips

  • The Centers for Disease Control and Prevention recommend that nebulizers be filled with sterile fluids (not tap or distilled H2O), and be changed or replaced every 24 hours.
  • Remember that cost, convenience and ease of use can affect compliance.
  • The efficacy of inhaled drugs can be affected by the device, the inhalation technique, severity of the disease and patient age.
  • Compressors must be evaluated for size, weight, noise, appearance and operating flow rates. Too slow or too fast will affect medication delivery.
  • Compressors must be places to prevent overheating and filters must be periodically cleaned or changed.
  • Heated nebulizers should be cleaned and changed periodically according to manufacturer recommendations. (Generally every day they should be washed with soap and water and air dried. Some non-disposables may be put in the dishwasher.
  • Nebulizers are evaluated for particle size, ease-of-use (assembly, cleaning) and durability.
  • Troubleshooting: Check compressor power cord, switch is on, check for leaks at nipple, check proper assembly of nebulizer, check jet holes for clogging and inspect compressor filter.

The American Association of Respiratory Care's Clinical Practice offers guidelines for selection of an aerosol delivery device

Source: "Oakes' Respiratory Home Care, An On-Site Reference Guide," By Dana Oakes, Kenneth Wyka and Kathleen Wyka.

This article originally appeared in the April 2006 issue of HME Business.

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