Hemodynamic Response to Fluid Boluses in Patients with Single-Ventricle Parallel Circulation

The purpose of this study is to assess the effect of fluid bolus in response to a hypotensive episode by evaluating high-fidelity hemodynamic data obtained from children with single-ventricle anatomy and parallel circulation. Single center, retrospective analysis of hemodynamic and oximetric data after fluid bolus administrations within the first 2 weeks post-surgery. A baseline (- 60 to - 10 min), hypotensive episode (- 10 to 0 min), and response interval (0 to 60 min) were defined to quantify the dynamics of vital signs. The responses assessed include heart rate, blood pressure, oxygen saturation, oxygen extraction ratios, and pulmonary-to-systemic flow ratios. Mixed effects models were used to account for the repeated measures over the response interval. The analysis included 67 fluid boluses. There is a decrease in heart rate and an increase in blood pressure during the response in comparison to the hypotensive time. These vitals rapidly return to the baseline values. The boluses induced a significant decrease in renal and cerebral oxygen extraction ratios, with no significant change in arterial oxygen saturation or pulmonary-to-systemic flow ratio. The type of bolus (normal saline versus albumin) did not affect the response in blood pressure. However, in comparison with albumin, normal saline had a more favorable effect on the renal and cerebral oxygen extraction ratios. This study demonstrates that fluid boluses are an effective rescue medication for hypotensive episodes in children with parallel circulation by improving hemodynamics, as well as markers of oxygen delivery. The type of bolus (normal saline versus albumin) did not affect the blood pressure response. However, normal saline had a more pronounced effect on the renal and cerebral oxygen extraction ratios than albumin.