Résumé
In case of refractory shock, high norepinephrine dose can be required. The maximal norepinephrine dose (ND) associated with mortality remains questioned. A norepinephrine dose > 1 µg/kg/min seems to be associated with mortality, but this critical threshold needs to be confirmed. The aim of the present study was to confirm if a norepinephrine dose > 1 µg/kg/min predicts mortality in intensive care unit (ICU) patients. Methods: retrospective analysis of ICU patient’s data receiving norepinephrine for circulatory shock in ICU (Nimes University Hospital, France from January 2016 to December 2019). The primary aim was to determine if a maximal ND > to 1 µg/kg/min during the 5-days following start of norepinephrine infusion predicts hospital mortality. The secondary aims were to assess relationship with maximal norepinephrine dose and mortality, norepinephrine kinetics and mortality and description of norepinephrine dose between survivors and non-survivors. Results: on 3 693 screened patients, 3 432 patients were analyzed. Norepinephrine infusion at a dose > 1 µg/kg/min was associated with mortality: Hazard Ratio = 7.46 [6.34 ; 8.81]. The area under the receiver operating characteristic (ROC) was 0,79 for the maximal ND [0.77 ; 0.81]. The calculated critical threshold of 1,13 µg/kg/min for the maximal ND was the best prognostic value. Among 1 079 patients with a ND > 1 µg/kg/min, the mortality rate was 69% at 5 days. Norepinephrine kinetics was different in survivors and non-survivors. A significant constant decrease of ND over the study period was observed in survivors (p < 0.0001). In non survivors, ND remains significantly high and constant during the first 4 days, with a significant decrease only observed at day 5 (p < 0.001). Conclusion: the infusion of norepinephrine dose greater than 1 µg/kg/min is associated with a 5-days ICU mortality in patients with circulatory shock.