Correlation of values of central venous oxygen saturation, lactate and hematocrit in responsive and unresponsive dogs to fluid therapy during abdominal surgical procedures associated with hypovolemia

Abstract

Studies in humans have been demonstrating the importance in early recognition of tissue hypoxia in serious patients through variables of tissue oxygenation and perfusion, such as central venous oxygen saturation (ScvO2) and serum lactate. The ScvO2 and the lactate values conjunctly with others clinical and vital parameters have increased the detection accuracy of tissue hypoxia in serious patients, increasing your survival. In Veterinaty Medicine there are a few studies involving the ScvO2 in dogs, specially in responsive and non-responsive animals to fluid therapy. Therefore, the present study intends to evaluate the hemodynamics parameters and perfusion and tissue oxygenation indicators, such as ScvO2, serum lactate and hematocrit (Ht), after the volemic expansion in dogs, focusing on the roles of these variables as prognostic markers in animals considered responsive and non-resposive to the hydric challenge.For that, 20 adult animals submitted to abdominal surgeries will be selected. The animals presenting hypotension (MAP < 75mmHg) will be submitted to initial volemic expansion with lactated Ringer solution (20ml/kg during 20 minutes). All hemodynamic, metabolic and oxygenic parameters will be measured before and after the volemic expansion. The animals will be evaluated through the transesophageal echocardiogram to determine the responsivity to fluid therapy. The animal division will be held in two groups: the responsive and non-responsive to volemic expansion. The ones who present a cardiac index increase of 15% after the volemic expansion will be placed in the first group and those who don't show a response on this magnitude, in the second. The values of Ht, ScvO2 and lactate serum will be analyzed e correlated pair to pair, aiming to demonstrate a relation between the parameters in each group and between the two groups of animals. Linear correlations will be held through the Spearman test. P values < 0.05 will be considered statistically significant.