Évaluation de l’Élastance Artérielle Dynamique (Eadyn) comme marqueur prédictif d’augmentation de la Pression Artérielle Moyenne en réponse à une épreuve de remplissage vasculaire au bloc opératoire

Background: Intraoperative hemodynamic optimization strategy is based on cardiac output (CO) maximization using volume expansion (VE). Dynamic parameters such as stroke volume variation (SVV) and pulse pressure variation (PPV) may be used as therapeutic goal. However, treatments of perioperative hypotension are unclear and poorly defined. Recently, a new index, dynamic arterial elastance (Eadyn), defined as the PPV to SVV ratio, was validated to predict an increase in mean arterial pressure (MAP) following VE in hypotensive (MAP < 65 mmHg) preload dependent patients. This index has never been studied during surgery. Main objective: To assess the ability of Eadyn to predict the increase in MAP following a fluid challenge during surgery. Methods: Patients undergoing major surgery (vascular, orthopedic, neurosurgery) with invasive hemodynamic monitoring (FloTracTM / VigileoTM). Measurements of HR, MAP, SV, CO, PPV, SVV and Eadyn were made before and after a volume expansion using hydroxyethylstarch 500cc 130/0.4 at 6% (Voluven®). Patients were defined as responders if MAP increased by ≥ 15% and non-responders otherwise. Results: 112 patients were enrolled. 27 patients (24%) were responders and 85 (76%) were not. The values of PPV, SVV and Eadyn before the VE were not different between the 2 groups. The value of Eadyn before the VE was not correlated to the percentage increase in MAP. The area under the ROC curve of Eadyn before VE was not significantly different from 0.5 (0.55 ± 0.06, 95%Confidence Interval [0.46 to 0.65], p = 0.39). Conclusion: Our study suggests that Eadyn is not able to predict an increase in MAP in response to VE in unselected patients during surgery.