Maximum Norepinephrine Dosage Within 24 Hours as an Indicator of Refractory Septic Shock: A Retrospective Study

Abstract

Background: The management of refractory septic shock remains a major challenge in critical care and its early indicators are not fully understood. We hypothesized that the maximum norepinephrine dosage within 24 hours of intensive care unit (ICU) admission may be a useful indicator of early mortality in patients with septic shock. Methods: In this retrospective single-center observational study, patients with septic shock admitted to the emergency ICU of an academic medical center between April 2011 and March 2017 were included. Individuals with cardiac arrest and those with do-not-resuscitate orders before admission were excluded. We analyzed if the maximum norepinephrine dosage within 24 hours of ICU admission (MD24) was associated with 7-day mortality. Results: Among 152 patients with septic shock, 20 (15%) did not survive by day 7. The receiver operating characteristic curve analysis for predicting 7-day mortality revealed a cutoff of MD24 of 0.6 μg/kg/min (sensitivity 47%, specificity 93%). In the multivariable regression analysis, a higher MD24 was significantly associated with 7-day mortality (odds ratio: 7.20; 95% confidence interval [CI]: 2.02-25.7; P = .002) but not with 30-day mortality. Using the inverse probability of treatment weighting method in a propensity scoring analysis, a higher MD24 was significantly associated with 7-day (hazard ratio [HR]: 8.9; 95% CI: 3.2-25.0; P < .001) and 30-day mortality (HR: 2.7; 95% CI: 1.2-5.8; P = .012). Conclusions: An MD24 ≥0.6 μg/kg/min was significantly associated with 7-day mortality in patients with septic shock and may therefore be a useful indicator of refractory septic shock.