Outcomes Associated With Norepinephrine Use Among Cardiac Intensive Care Unit Patients with Severe Shock

Background: Recent data suggests improved outcomes among cardiac intensive care unit (CICU) patients treated with norepinephrine, especially patients with severe shock. We aimed to describe the association between norepinephrine and mortality in CICU patients with severe shock, defined as those requiring high-dose vasopressors (HDV).Materials and Results: We retrospectively evaluated Mayo Clinic CICU patients treated with vasopressors from 2007 to 2015. HDV was defined as a peak Cumulative Vasopressor Index of four for any vasopressor. Peak norepinephrine equivalent (NEE) dose was used to compare vasopressor doses. Multivariable logistic regression was used to determine predictors of hospital mortality. Results: We included 2,090 patients with a median age of 69years (IQR 59-78), including 35% females; 44% of patients received HDV. Hospital mortality was higher among patients receiving HDV (42% vs. 16%, unadjusted OR 3.87, 95% CI 3.16-4.75, P<0.01). On multivariable analysis in HDV patients, hospital mortality increased with rising peak NEE (adjusted OR 1.02 per 0.01mcg/kg/min, 95% CI 1.01-1.02, P<0.01) and the use of NE was associated with lower hospital mortality (adjusted OR 0.46, 95% CI 0.31-0.72, P<0.01). After adjustment for illness severity, peak NEE and norepinephrine use were not associated with mortality among patients who did not require HDV. Conclusions: Mortality is high among CICU patients requiring HDV, and rises with increasing vasopressor requirements. Use of NE was associated with lower mortality among patients requiring HDV, but not among those without HDV, implying that patients with more severe shock may benefit from preferential use of NE.