Top Tip 1 - Cardiology - Using Sleeping Respiratory Rate in Animals with Cardiac Disease

In the Cardiorespiratory Department at SARC we regularly ask owners of animals with cardiac disease to monitor their pet’s Sleeping Respiratory Rate (SRR). This is a simple tool your clients can use at home as an indicator of developing pulmonary oedema or pleural effusion in dogs and cats.

In addition to being a great home monitoring aid, involving the owner in this process helps overcome the "need to do something" that many owners and veterinarians exhibit when dealing with heart disease.

Download your own copy of the SRR Monitoring Sheet for your clients

Why monitor Sleeping Respiratory Rate (SRR)?

Owner participation in assessing and recording of Sleeping Respiratory Rate is:

* Probably the most sensitive indicator of developing pulmonary oedema or pleural effusion in dogs and cats.

* A very useful home-monitoring technique for owners to perform

* Useful once a diagnosis of CHF has been made (and is now controlled with frusemide), or where substantial heart disease exists and is likely to result in CHF at some future stage.

How is it done?

Have the owner record the sleeping respiratory rate of their pet (number of breaths/min). The recording should be done when the animal is asleep in a thermo-neutral environment (ie, not too cold, not too hot) and not if the animal is dreaming. This should be repeated daily for 2-3 days (to get a baseline variation), and then once or twice weekly.

If the SRR changes substantially between measurements, the owner should then measure daily to confirm the change, or to document a trend. If a trend is documented, the owner should contact the veterinarian for further evaluation.

What is the normal SRR?

Normal SRR in dogs and cats is <30 breaths/min, often in the high-teens or low 20s.

Consistent SRR >30 breaths/min in patients with underlying heart disease is strongly suggestive of developing CHF. However, primary respiratory disease with concurrent subclinical heart disease needs to be ruled out.

If the dog or cat is currently receiving frusemide for congestive heart failure and the respiratory rate is consistently >30breaths/min this would suggest a reoccurrence of the pulmonary oedema of pleural effusion.

What do I do if SRR is high?

If SRR is elevated, thoracic radiographs and physical examination should be performed. If there is no clear evidence of CHF, a short diuretic trial can be employed (frusemide @ 2mg/kg BID for 3-4 days). A reduction in the SRR to baseline with therapy further supports mild CHF.

If the animal is already receiving frusemide for confirmed congestive heart failure then an increase in the frusemide dose can be trialed. If there is no improvement on an increased dose then thoracic radiographs should be performed to assess for pleural effusion that may need to be drained or another cause for the increased respiratory rate.

Low normal SSR after treatment with frusemide

If the dog or cats respiratory rate is <25breaths/min after receiving therapy for congestive heart failure then the frusemide dose could potentially be reduced, especially if there are problems regarding renal insufficiency, but if the SSR increases to consistently >30breaths/min then the frusemide dose will need to be increased again.

Disclaimer for non-veterinarians: This information is of a general nature only and is intended to be used as part of overall case management for a condition diagnosed and managed by a qualified veterinarian. Always consult a qualified veterinarian for advice specific to your own pet.

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