Lung function is critical to ensuring equine performance and overall health. Heaves, allergies, asthma, and pneumonia are common health concerns that can impact respiratory capacity during exercise and at rest in horses.

These conditions are all characterized by inflammation in the lungs, which can affect athletic performance and well-being in your horse. One strategy to treat respiratory inflammation is delivering medication directly into the lungs using a nebulizer.

Equine nebulizers work by converting liquid medication into a fine mist (aerosol particles), which the horse breathes in. The functional parts of a nebulizer are the nebulizing system that creates the mist particles, a medication reservoir, and a mask that goes over the horse’s nose.

Nebulizers are a popular choice for treating respiratory dysfunction because localized dosing reduces the risk of side effects and ensures a high concentration of medication is delivered directly to the lungs.

Types of Nebulizers for Horses

There are three basic types of nebulizers for horses: jet, ultrasonic, and mesh. [1] Which type of nebulizer to use depends on what medication is prescribed for the horse’s condition.

Medications that are very viscous (i.e. are a thick liquid) or that break down when heated cannot be used in all types of nebulizers. [2] Always follow your veterinarian’s recommendations and the instructions on the prescription label before purchasing a nebulizer for your horse.

Jet Nebulization

Jet nebulizers use pressurized gas to create aerosol particles of medication for inhalation by the horse. [1] Most medications are suitable for use in a jet nebulization system, although the high-pressure gas may break down large-molecule drugs. [2]

Some challenges to consider before selecting a jet nebulizer include: [1][3][4]

  • Loud noise, which may frighten some horses
  • Requires a compressed air source, which adds cost and storage demands, and is a safety concern
  • Administering a dose can take a significant amount of time; horses may become impatient and require specific training to take the medication
  • Uptake of the drug by the horse’s body may be less effective compared to other types of nebulizers
  • Not portable

Ultrasonic Nebulization

Ultrasonic nebulizers use a mechanism to stimulate electronic vibration in a special type of crystal. High speed vibration of the liquid medication produces fine aerosol droplets for inhalation. [1]

These nebulizers take less time to dispense medication than jet nebulizers, and typically the aerosol particles deliver a higher concentration of medication. [4]

Ultrasonic nebulizers are limited in terms of which medications they are appropriate for. Thick (viscous) liquid formulations do not aerosolize appropriately in this type of nebulizer. [1] Ultrasonic nebulizers also produce heat, which may inactivate some medications. [1]

Mesh Nebulization

Mesh nebulizers are currently the most common type of nebulizer used for horses. [3] These nebulizers force liquid through a mesh to produce fine particles. [1]

Mesh nebulizers are the most expensive of the three types, however offer many benefits specific to equine use, including: [1][3]

  • Silent operation
  • Adjustable particle size
  • Less time needed to dispense a dose
  • Wireless options are available

Mesh nebulizers also require low viscosity medication to prevent clogging pores in the mesh. [1] These types of nebulizers are also more difficult to clean than the other types. [1]

Horse Nebulizer for Respiratory ConditionsIllustration:

How to Use A Nebulizer

Regardless of which type of nebulizer is most appropriate for your horse’s specific needs, there are some basic operating and training guidelines to keep in mind before you use one. If you are unsure about your horse’s comfort with using a nebulizer, your veterinarian can provide expert tips and feedback.

Habituation

Using a nebulizer begins with a habituation period for the horse. The nebulizer mask fits over the nose and forms a seal, which can be uncomfortable or frightening for the horse. [5]

Before placing the mask, show it to the horse and allow them to investigate by taking in smells and looking at it. [5]

Once the horse appears comfortable with the nebulizer, place the mask over the nose without any medication canisters attached to the nebulizer, to allow them to practice wearing it while they breathe normally. [5]

Once the horse can comfortably wear the nebulizer and breathe comfortably, treatment can begin. [5]

Treatment

To dispense medication using the nebulizer, the medication reservoir must be filled prior to fitting the mask on the horse. [5] Some medications need to be mixed with pharmaceutical grade saline (salt water solution) in the reservoir before dosing.

Always follow the instructions from your prescribing veterinarian to determine appropriate dosage and dilution, and do not attempt to mix saline solution at home. It is important to follow these recommendations closely to ensure adequate medication delivery and effective treatment.

Once the mask is in place, close the vent allowing outside air into the chamber and activate the nebulizer. [5] After activating, the chamber of the mask fills with aerosolized medication. As the horse inhales, handlers can observe the medication disappearing from the mask. [5]

If the horse becomes uncomfortable during treatment, the vent can be opened slightly to let more outside air into the mask chamber. [5] When the horse relaxes, the handler can close the vent again. [5]

Cleaning

Cleaning is an important part of nebulizer use, as contamination or bacterial growth in the nebulizer equipment may cause respiratory infections. [4][6]

Specific cleaning requirements and methodology depend on the type of nebulizer used. The manufacturer’s cleaning directions should be carefully followed after each use of the nebulizer.

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Benefits of Nebulizing Medication

Nebulization of medication has many benefits over systemic (whole body) administration, such as intravenous infusions, intramuscular injections, or oral medications.

Systemic medications circulate through the entire body, spreading to all organs and tissues. This often results in needing higher doses of medication to ensure the targeted organ receives enough drug to effectively treat symptoms. [6]

The lungs have a higher risk of inadequate drug delivery, as there is a blood-bronchial barrier between the bloodstream and airways. [6] This barrier impedes passage of some medications from the bloodstream into the airways, significantly reducing the efficacy of systemic medications in the lungs. [6]

Direct Dosing

In contrast, the main benefit of aerosolized medication is that inhalation provides localized, concentrated, direct dosing to the respiratory system. [6] Inhaled medications bypass the blood-bronchial barrier, delivering the medication directly into the airways. [6]

By delivering medication to the the lungs directly, the same effect as systemic medications is achieved at much lower dosage.