Echocardiographic measure of dynamic arterial elastance predict pressure response during norepinephrine weaning: an observational study

The purpose of this study was to determine whether dynamic elastance E-Adyn derived from echocardiographic measurements of stroke volume variations can predict the success of a one-step decrease of norepinephrine dose. In this prospective single-center study, 39 patients with vasoplegic syndrome treated with norepinephrine and for whom the attending physician had decided to decrease norepinephrine dose and monitored by thermodilution were analyzed. E-Adyn is the ratio of pulse pressure variation to stroke volume variation and was calculated from echocardiography stroke volume variations and from transpulmonary thermodilution. Pulse pressure variation was obtained from invasive arterial monitoring. Responders were defined by a decrease in mean arterial pressure (MAP)>10% following norepinephrine decrease. The median decrease in norepinephrine was of 0.04 [0.03-0.05] mu g kg(-1) min(-1). Twelve patients (31%) were classified as pressure responders with a median decrease in MAP of 13% [12-15%]. E-Adyn was lower in pressure responders (0.40 [0.24-0.57] vs 0.95 [0.77-1.09], p<0.01). E-Adyn was able to discriminate between pressure responders and non-responders with an area under the curve of 0.86 (CI95% [0.71 to1.0], p<0.05). The optimal cut-off was 0.8. E-Adyn calculated from the echocardiographic estimation of the stroke volume variation and the invasive arterial pulse pressure variation can be used to discriminate pressure response to norepinephrine weaning. Agreement between E-Adyn calculated from echocardiography and thermodilution was poor. Echocardiographic E-Adyn might be used at bedside to optimize hemodynamic treatment.