TDK conference 2022

Several theoretical models are available for the assessment of Acid Base Balance (ABB), of which the Henderson-Hasselbach equation is the most widely used in veterinary clinical practice. Although the limitations of the classical approach are well known, its rapid, simple and transparent applicability makes it superior to other models. Compared to the traditional model, physicochemical and semi-quantitative methods can provide a wealth of valuable information that can offset the complexity and difficulty of these methods.

The aim of this retrospective study was to compare the diagnostic applicability of different theoretical models used to assess ABB.

A total of 51 animals, of which 37 (72.55%) dogs and 14 (27.45%) cats, were analysed between December 28. 2019. and March 31. 2022. They were patients of the Small Animal Clinic of the University of Veterinary Medicine Budapest, and were subjected to simultaneous acid-base and biochemical blood examinations.

Blood was collected in a standardized manner, after hair removal and disinfection with ethyl alcohol, in case of acid-base testing, in a BGS (Blood Gas Sampling System) syringe with closed technique. The blood taken for acid-base testing was analyzed immediately after blood was collected using an EPOC analyzer. For biochemical testing, blood samples were taken from the same puncture, either closed or open; these were sent on to the University's Department of Pathophysiology and Oncology Laboratory. The results of the blood tests were searched from the university database, with the requirement that the time between the two tests should not exceed 4 hours.

The Henderson-Hasselbach approach identified 17 (33.33%) cases of simple acid-base disturbance, of which 8 (15.69%) were respiratory acidosis, 2 (3.92%) respiratory alkalosis, 5 (9.80%) metabolic acidosis with normal anion gap (AG), 1 (1.96%) metabolic acidosis with increased AG, 1 (1.96%) metabolic alkalosis. 16 cases of mixed acid-base disturbances were identified, of which 1 (1.96%) was metabolic acidosis with respiratory acidosis, 6 (11.76%) was metabolic acidosis with respiratory alkalosis, 9 (17.65%) was metabolic alkalosis with respiratory acidosis. The Stewart physicochemical and Fencl-Stewart base excess (BE) models identified more cases of metabolic acid-base abnormalities and increased presence of unmeasured anions (UA-) than the conventional approach.