EN
The objective of these studies was to introduce the Stewart approach to analyses of acid-base changes in dogs with the chronic renal failure (CRF). The acid-base status was investigated in 12 healthy dogs and 20 dogs with CRF. In the CRF affected dogs the level of urea and creatinin rose to 350 mg/dl and 394.8 µmol/l respectively. The three independence variables (Pсо₂, SID-strog ion difference, and the Atot-sum of net charges of nonvolatile plasma buffers (albumin + inorganic phosphate) together with the strong ion gap (SIG) were calculated by a method adopted from articles employing Stewart’s approach. The SID averaged 41.85 mEq/l and 48.81 mEq/l in normal and diseased dogs respectively. Nonvolatile plasma buffers (Atot) were higher especially in more severely diseased dogs. The most considerable changes in affected dogs have been observed in SIG where, together with the increasing values of urea, the quantity of SIG successively dropped, attaining negative values (-28.03 mEq/l). The albumin values were significantly associated with the SID values. All affected dogs have metabolic acidosis partly compensated by respiratory alkalosis. As has been clearly observed the estimation of SIG may be used as an accurate marker of CRF in dogs.