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Monitoring Dynamic Arterial Elastance as a Means of Decreasing the Duration of Norepinephrine Treatment in Vasoplegic Syndrome Following Cardiac Surgery: A Prospective, Randomized Trial
Guinot PG, Abou-Arab O, Guilbart M, et al. Intensive Care Med. 2017; 43: 643-51.
Study Question: Will the use of an algorithm based on dynamic arterial elastance (Eadyn) (a functional index of arterial tone) decrease the duration of norepinephrine infusion in patients following cardiopulmonary bypass?
Study Description: This was a randomized, single-center, open-label clinical trial conducted in a tertiary university hospital between October 2014 and August 2016. Adult cardiac surgery patients demonstrating post-surgical vasoplegic syndrome following cardiopulmonary bypass were included. Patients who had a mean arterial pressure (MAP) > 70 mmHg and had received more than 4 h of norepinephrine therapy were included. Norepinephrine was weaned according to an algorithm based on the Eadyn (measured via femoral arterial catheter) and MAP in the intervention and control groups, respectively. The primary outcome was duration of norepinephrine infusion. Secondary outcomes included cumulative dose of norepinephrine, diuresis and total fluids infused, arterial lactate levels, ScvO2, arrhythmia, death and ICU LOS.
Results: There were 118 patients in the intention-to-treat analysis (n=59 in each group). There was no difference in baseline characteristics between groups. Patients in the intervention group received norepinephrine infusions for a shorter duration (17 h vs. 39 h; p<0.001) as well as less cumulative total norepinephrine (4.96 mg vs. 11.4 mg; p=0.015) than the control group. A shorter ICU LOS was demonstrated in the intervention group (2 d vs. 3 d; p=0.021). No differences were noted between groups in perfusion parameters or volume of infused fluid.
Conclusion(s): In cardiac surgery patients with vasoplegic syndrome, use of an Eadyn-based algorithm was associated with shorter duration of norepinephrine infusion and shorter ICU LOS than patients receiving norepinephrine titration based on MAP.
Perspective: Vasoplegic syndrome following cardiopulmonary bypass is characterized by severe hypotension with low systemic vascular resistance and normal or high cardiac output. Eadyn, defined as the ratio of pulse pressure variation to stroke volume variation, has been proposed as a functional assessment of arterial tone. Previous clinical trials have demonstrated the ability of Eadyn to predict arterial pressure response to fluid expansion as well as decreases in blood pressure in septic patients undergoing norepinephrine weaning. Based on the results of this study, Eadyn can be considered to provide an individualized approach to norepinephrine management in patients with vasoplegic syndrome following cardiopulmonary bypass.