A103-08 Dynamic Arterial Elastance as a Predictor of Mean Arterial Pressure Increase After Fluid Challenge in Patients With Acute Brain Injury: A Pilot Study

Rationale Dynamic arterial elastance (EaDyn), defined as the ratio of pulse pressure variation (PPV) to stroke volume variation (SVV), reflects arterial tone and ventriculo-arterial coupling. In patients with acute brain injury, maintaining cerebral perfusion pressure is crucial, yet predicting hemodynamic response to fluids remains difficult. Among preload-dependent patients—those who increase cardiac output (CO) after a fluid challenge—it is unclear whether EaDyn can identify those who will also exhibit a significant rise in mean arterial pressure (MAP). This pilot study evaluated the ability of EaDyn to predict MAP increase following a fluid challenge in preload-dependent patients with acute cerebrovascular lesions. Methods A prospective observational study was performed in intensive care patients with acute brain injury due to ischemic or hemorrhagic stroke (ACV), subarachnoid hemorrhage (HSA), or traumatic brain injury (TBI). Demographic, clinical, and ventilatory data were recorded before a 4 mL/kg crystalloid bolus over 10 minutes. EaDyn was calculated as PPV/SVV before (T1) and after (T2) fluid administration. Patients were classified as fluid responders if CO increased ≥10%. The predictive ability of baseline EaDyn for a ≥ 10% MAP rise was analyzed among these preload-dependent patients. Continuous variables were summarized as medians (IQR) and compared with the Wilcoxon rank-sum test. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis, sensitivity, specificity, and the Youden index. Results Twenty-four patients were included (median age 56 years [37.8-66.0], 75% female, BMI 24.2 kg/m² [22.7-28.1]). All were mechanically ventilated. Etiologies included stroke (42%), subarachnoid hemorrhage (29%), and TBI (29%). Median driving pressure was 8.5 cmH2O [7.7-11.3], compliance 45.0 mL/cmH2O [37.3-63.5], and PaO2/FiO2 ratio 257.5 [180.0-305.3]. Eight patients were fluid responders (CO ≥ 10%); among these, six showed a MAP increase ≥ 10%. Baseline EaDyn was lower in non-responders (0.56 [0.47-0.66]) than in responders (1.00 [0.94-1.06]) (p = 0.05). The optimal cutoff (Youden index) was EaDyn ≥ 0.875, with 100% sensitivity and specificity. Due to the small sample size, AUC estimation was not feasible, and findings may reflect overfitting. Conclusions In this pilot cohort, higher baseline EaDyn was associated with MAP increase after fluid loading among preload-dependent patients with acute brain injury. Although diagnostic performance appeared optimal, these results are exploratory and require confirmation in larger studies to establish EaDyn’s predictive role in this context. This abstract is funded by: None