Norepinephrine Load and Relationship With Prognosis in Critically Patients With Circulatory Shock

Norepinephrine is recommended as first-line vasopressor in critically ill patients, regardless of shock etiology. Its advantages over dopamine and/or epinephrine have been demonstrated, especially by reducing tachycardia events. The current guidelines recommend a mean arterial pressure of at least 65 mmHg that in the resuscitation from sepsis-induced hypoperfusion. Some study reported that delay in initiation of vasopressor therapy was associated with an increase mortality risk in patient with septic shock .The recent experts' opinion suggest that " vasopressors should be started early, before (complete) completion of fluid ressuscitation ".

In the event of refractory septic shock, high-dose vasopressors may be used. The precise maximal dose of norepinephrine associated with mortality excess has been poorly studied. High doses have been defined by a cutoff value ranging from 0.5 μg/kg/min to 2 μg/kg/min and recently by 1 μg/kg/min for mortality at 90% and by 0,75 μg/kg/min for mortality at 60%. Furthermore, an increasing vasopressor dosing intensity during the first 24 hours after shock septic was associated with increased mortality depending of fluid administration. If a threshold value of norepinephrine score can be obtained, it could indicate the association with another vasopressor such as vasopressin or surrogates.

The primary aim of the present study aimed to confirm if a given norepinephrine dose is associated with mortality. The secondary aims were the link between mortality and norepinephrine duration, cumulative dose in order to build a score that predicts a futility of increasing norepinephrine dose.