Dog nebulisers are an underused therapeutic option for dogs with respiratory issues. While saline nebulisers may help to loosen mucus2, nebulisers can also be a valuable method of localised drug delivery.
Corticosteroids are widely used to manage respiratory diseases including bronchitis, laryngitis, tracheitis and allergic lung disease in companion animals, but systemic administration often comes with significant side effects. Inhaled corticosteroids are much less well absorbed into the systemic circulation and can be better tolerated.3,4
Metered dose inhalers are commonly used for delivery of inhaled medications, but dog nebulisers are another effective option and according to this study may offer more effective delivery of corticosteroids to the lungs.
To date no previous studies have assessed the deposition of radiolabelled aerosols in conscious dogs; the results for nebuliser treatment of dogs are promising.
Key points:
- Long-term treatment with corticosteroids and other medications is necessary to manage many respiratory diseases, but can cause substantial side effects, which are minimised by inhaled drug delivery.
- Nebulisation and metered dose inhalers have both been used to deliver medications to the lungs in companion animals.
- In this randomised crossover pilot study, nebulisation achieved significantly higher deposition of radiolabelled fluticasone in the lungs than metered dose inhalers in dogs.
Study set-up
This was a prospective, randomised crossover pilot study of radiolabelled fluticasone deposition administered via either nebuliser or metered dose inhaler (MDI), with a 7-day washout period between tests.
Subjects: 10 healthy foxhounds between 2 and 6 years old with no history of respiratory issues within the previous 4 weeks and no health issues detected on physical examination and thoracic radiography.
Administration: after 2 short training sessions, dogs were randomly allocated to the two groups. Acepromazine sedation was used but all the dogs were conscious and breathing unassisted during the study.
A subsequent second study on 6 of the dogs was carried out without any sedation (after further training) to compare nebulisation and MDI in un-sedated dogs.
Nebulisation: a jet nebuliser and liquid nebules containing fluticasone propionate mixed with a technetium compound were used. Dogs then breathed tidally from the canine nebuliser for 1 minute.
MDI: a commercially available metered dose inhaler for dogs containing fluticasone propionate was sourced and sodium pertechnetate was used for radiolabelling. Each dog was given two actuations from the MDI, and after each they were allowed 5 tidal breaths.
Assessment: after aerosol inhalation, 2D planar scintigraphy was performed immediately, obtaining a number of views of the chest, abdomen, head and neck over approximately 20 minutes.
Regional deposition was then calculated based on manual counts and analysed.
Findings
Nebulisation in dogs produced significantly higher respiratory tract deposition than MDI (P = 0.027), with 7 out of 10 dogs achieving higher respiratory tract deposition with nebulisation over MDI. The mean deposition for nebulisation was 4.2% (SD, 1.4%) compared to 2.3% (SD, 1.4) for MDI.
After nebulisation, respiratory tract deposition was linearly correlated with dose administered, but this relationship was not present after treatment with the MDI.
Radiolabelled fluticasone was identified in both central and peripheral areas of the lung for both devices, but was reported to be subjectively more uniform throughout the lung after nebulisation.
Nebulisation also resulted in 44.7% greater deposition within the head and gastrointestinal tract when compared to MDI (P < 0.0001), which achieved 23% greater deposition within the equipment itself (P = 0.0002), potentially due to larger particles coming into contact with the walls of the spacer of the MDI. This may lead to increased systemic absorption of medications delivered via nebulisation compared to MDI, which could be a concern in patients susceptible to systemic side effects.
The subsequent study of 6 dogs without sedation revealed no significant difference between sedated and un-sedated values (P = 0.68).
Overall, respiratory tract deposition from both the nebuliser and MDI were low compared to similar studies in adult humans; however, drug delivery was similar to previous studies in infants and toddlers, likely due to pets’ and children’s reliance on tidal breathing rather than forceful or prolonged breaths during dosing.
The studies’ authors hypothesise that nebulisation may be more effective in dogs due to the continuous nature of the treatment, compared to MDI in which non-compliance during a pulse of treatment may significantly impact administration; this may also explain the correlation between administered dose and after nebulisation but not MDI.
Dog nebulisers: an effective method of respiratory drug delivery
While inhaled corticosteroid treatments have become more widely used due to their reduced side effect profile compared with oral medication, little previous research has compared the use of dog nebulisers and metered dose inhalers.
This pilot study suggests steroid nebulisation in dogs could be more effective than steroid MDI, offering increased drug delivery and subjectively more uniform distribution throughout the lungs. Systemic absorption may also be increased relative to MDI, so this should be kept in mind when treating particularly steroid sensitive patients.
Nebulisation may also be preferable to an MDI for patients that struggle with compliance, as the MDI is more reliant on a close mask seal and inhalation during the pulsatile release of medication, while nebulisation offers a more continuous aerosol flow.
The Flexineb C2 offers an effective and easy-to-use canine and feline nebulisation option for saline, corticosteroids, bronchodilators and other medications. Offering both cage or kennel mounting and a range of face masks, the nebuliser can be used for a wide range of patients and can improve compliance with long-term treatment plans by limiting systemic side effects and reducing the stress associated with inhalational treatments.
Find out more about the Flexineb C2 or read the Flexineb C2 FAQs.