de Courson H, Boyer P, Grobost R, et al. - In hypotensive and preload-responsive patients, researchers assessed the evolution of dynamic arterial elastance (Eadyn; defined as the ratio between pulse pressure variations and stroke volume variations) during volume expansion and the impacts of neosynephrine infusion. The study population included 56 mechanically ventilated patients in the operating room. According to this prospective bicentre study, 21 patients were pressure responders to volume expansion. Neosynephrine infusion caused a reduction in Eadyn related to a decrease in pulse pressure variations more pronounced than the reduction in stroke volume variations. Baseline and changes in Eadyn after neosynephrine infusion were only associated with heart rate. Overall, the authors concluded that Eadyn is a potential sensitive marker of arterial tone changes after vasopressor infusion.