A0015 Assessment of Dynamic Predictors of Fluid Responsiveness in Patients Undergoing Supratentorial Neurosurgery Using Transesophageal Echocardiography

Background: Patients presenting for neurosurgery are at risk of hypovolemia due to ongoing osmotherapy, neuroendocrine responses, nausea, and vomiting. Fluid therapy is frequently used in neurosurgical patients to improve hemodynamics. Only 40 to 70% of patients respond to volume expansion. The aim of this study was to assess the utility of newer dynamic predictors of fluid responsiveness such as delta down (DD), superior vena cava collapsibility index (SVCCI), and aortic velocity time integral variability (VTIAoV) in patients undergoing neurosurgery.

Materials and Methods: Thirty patients undergoing neurosurgery for supratentorial craniotomy and excision were enrolled in this prospective study. Post-induction, vitals, anesthetic parameters, and study variables were recorded as the baseline. Following this, patients received a fluid bolus of 10 mL/kg of colloid over 20 minutes, and measurements were repeated post loading. Data were expressed as mean ± SD. Comparison of normally distributed continuous variables was evaluated with Student's t-test, and p < 0.05 was considered as statistically significant. The predictive ability of variables for fluid responsiveness was determined using Pearson's coefficient analysis (r).

Results: There were 22 volume responders and 8 non-responders. DD > 5 mm Hg was efficient in differentiating the responders from nonresponders (p < 0.05) with a sensitivity and specificity of 90% and 85%, respectively, with a predictive ability, r = 0.716. SVCCI of > 38% was 100% sensitive and 95% specific in detecting the volume status and in differentiating the responders from nonresponders (p < 0.05) with an excellent predictability, r = 0.906. VTIAoV > 20% too proved to be a good predictor, with a sensitivity and specificity of 100% and 90%, respectively, with a predictive power, r = 0.732.

Conclusions: Our study showed that 73.33% of patients presenting for intracranial surgeries were fluid responders despite static indices of hemodynamics like heart rate, blood pressure, and CVP being within the normal range. Among the variables, SVCCI > 38% is an excellent predictor followed by VTIAoV > 20% and DD > 5 mm Hg in assessing the fluid status in this population.