Lactate is produced in the organism in a big or small scale, depending on the presence or absence of oxygen for ATP generation. Situations of tissue hypoxemia raise its plasmatic levels, which should stay, in the dog, between 0.3 and 2.5mmol L-1. This study aimed to evaluate the tissue perfusion through blood lactate in dogs submitted to thoracic peridural anesthesia. For such, eight dogs with MAC previously determined for isoflurano, were divided into two experimental groups and were induced and maintained with isofluorane. The dogs had their spinal low lumbar space reached with an epidural catheter, inserted to the T1-T2 interval, with later application of ropivacaine in two different volumes, one for each group: 0.25ml kg-1 (GR1) and 0.33ml kg-1 (GR2). The animals were monitored at nine total moments of anesthesia and electrostimulation in the radio-ulnar region was made to detect the presence of the local block, with evaluation of the following parameters: lactate levels, mean arterial pressure, hemogasometric variables, heart rate and respiratory rate. Respiratory depression was observed, caused by the block, as well as an increase on the pH and slight reduction of HR and MAP. There was a significant decrease in lactate levels after anesthetic induction and a return to its basal levels after recovery, on both groups. There was no correlation between lactate and other evaluated parameters. The changes in lactate levels are probably related to the inhalant anesthesia, assuming an influence of isofluorane on this parameter. There was no influence of the local block on tissue perfusion, analized through blood lactate measures.
tissue perfusion; isoflurane; ropivacaine; hypoxemia
