Acid-base disorders are commonly identified in critically ill patients and evaluation of acid-base status has therefore become a common part of the clinical workup in such cases. It is suspected, based on sparse existing literature, that cats do not develop the respiratory compensation to a metabolic acid-base disturbance that is normal in humans and dogs. To diagnose and treat cats with metabolic acid-base disturbances correctly, it is important to establish if and to what degree respiratory compensation should be expected.

The objective of this study was to examine whether respiratory compensation can be detected by blood gas analysis in cats with metabolic acid-base disorders. This was carried out by evaluating blood gas analyses collected from cats during the last 15 years at the University Hospital for Companion Animals at the University of Copenhagen, Denmark. Each acid-base disturbance was classified by the use of pH, Pco2 and HCO3-. For metabolic disorders, respiratory compensation was evaluated by calculating the difference between the patient’s measured and expected Pco2 . A significant difference between the measured and expected Pco2 was found for this population of cats. Based on these findings, cats do not develop detectable respiratory compensation based on blood gas criteria established in dogs and humans.