The effect of fluid challenge on ventriculo-arterial coupling in an endotoxic shock swine bio-model Efectos del reto de líquidos sobre el acople ventrículo arterial en un biomodelo porcino de choque endotóxico

Abstract

Introduction: fluid challenges (FCs) consist of measuring hemodynamic response through changes in cardiac output (CO) after fluid administration, although only measuring CO proves insufficient. Ventriculo-arterial coupling (V-A) (effective arterial elastance / tele-systolic elastance: E(a)/Ets) are variables used for a comprehensive cardiac and circulatory status appraisal. Objective: to evaluate V-A in an endotoxic shock bio-model by FCs. Materials and methods: an endotoxic shock bio-model (9 pigs). Hemodynamic variables were measured every hour from time 0 (T0) to T6. Five FCs were performed between T0 and T4. Hypotension time was referred to as HT. The median differences in variables between T0-T4 were calculated. Challenges were classified into two groups according to V-A delta (post-challenge V-A - pre-challenge V-A). In ΔV-A≤0 o>0, variables were measured before and after each FC.  The lactate to pyruvate (L/P) ratio was determined at T0, T3 and T6. Correlations between the LP T6-T0 difference and hemodynamic variables, were established. Results: V-A increased (1.58 to 2,02, p=0.042) as Eae increased (1.74 to 2.55; p=0.017). CO (4.32 to 5.46, p=0.032) and cardiac power (CP) (0.61 to 0.77, p=0,028) increased, in the ΔV-AC≤0 group. The ΔLP correlated with the systolic and diastolic shock index (r=0.73), but not with V-A. Conclusion: V-A increased significantly during endotoxic shock. The ΔAVA≤0 group, showed elevated CO and CP during FC. ΔLP did not correlate with any of the V-A variables.