Acid-base balance is one the most important mechanism implied in the internal homeostasis of the organism. Acid-base balance is normally in a steady state because of constant production of carbon dioxide and fixed acids and their continuous removal by the respiratory system, metabolism and renal excretion. This equilibrium is fundamental especially in critical situation. However, it is so frequent that the acid-base balance screening will not carried out by default. The aim of the present work is to study the incidence of acid-basic disorders and its association with the severity of symptoms and the clinical diagnosis
Subjects were 200 patients (181 dogs and 19 cats). They were admitted in the ICU of our hospital. The assessment of the acid-base balance was justified by the severity of the illness. Blood samples were obtained from the jugular vein or from the femoral artery and they were collected in heparinized syringes. The samples were immediately submitted for analysis. The analyses were performed by a portable clinical analyzer (I-STAT,I-statâcorporation, East Windsor, NJ-USA). The parameters evaluated were: pH, PCO2, HCO3, TCO2, AGAP, BEXCS, Na, K, Cl, glucose, BUN, Hematocrit, Total proteins, PO2, SO2%, and PA-aO2. The SATISTICA package (StatSoft, Tulsa, USA) was used for the data analyses.
The data from the dogs and the cats were analyzed separately. Metabolic acidosis was found in 59 dogs, 41 of them compensated properly. Moreover, the dogs with metabolic acidosis which we have AGAP data, 20 showed a low AGAP and the rest showed normal values and only the 59.4% of them had hyperchloremia. Respiratory acidosis was found in 16 dogs. On the other hand, 2 dogs presented metabolic alkalosis and 22 dogs showed respiratory alkalosis, 31.8 % of them compensated properly. All of the cases with compensated respiratory alkalosis were classified as acute disorders. Mixed disorders (mainly respiratory alkalosis plus metabolic acidosis) were found in 41 dogs. And normal values in acid-base balance were only observed in 21 dogs. Regarding to the cats, metabolic acidosis was found in 4 cats, 3 of them compensated properly, and showed a low AGAP. Neither respiratory acidosis nor metabolic alkalosis were not observed in cats. On the other hand, respiratory alkalosis was found in 4 cats. Mixed disorders were found in 7 cats and, contrary to data from the dogs, only respiratory alkalosis plus metabolic acidosis was observed. Normal values in acid-base balance were only observed in 2 cats.
88% of the dogs and 89.5 % of the cats showed acid-base imbalance. Thus, most of patients that are admitted in the ICU showed acid-base disturbances. The most common problem in both species is the metabolic acidosis, and in a lower percentage the respiratory alkalosis and the mixed disorders. By contrast, metabolic alkalosis is found in rare cases. From our data no significant differences between dogs and cats were observed in the incidence of the acid-base imbalances. In our experience, besides the treatment of the primary problem, the recognition and properly treatment of the acid-base disorders are crucial in order to obtain successful results.