First-Line Vasopressor Use in Septic Shock and Route of Administration: An Epidemiologic Study

Rationale: Norepinephrine is a first-line agent for the treatment of hypotension in septic shock. However, its frequency of use and potential barriers to its use are unclear. Objectives: To evaluate the frequency of use of norepinephrine in septic shock, to identify potential barriers to its use, and to evaluate trends in use of vasopressors over time. Methods: We conducted a retrospective population-based cohort study of patients with septic shock in Alberta, Canada, between July 1, 2012, and December 31, 2018. The primary outcome was receipt of a first-line vasopressor other than norepinephrine ("nonnorepinephrine vasopressor"). Predictors of receiving a nonnorepinephrine vasopressor were assessed using a multivariable-adjusted, multilevel logistic regression model with intensive care unit as a random effect. Results: Among 6,343 patients with septic shock, the proportion of patients receiving nonnorepinephrine vasopressors as first-line treatment decreased steadily from 11.5% in 2012 to 3.0% in 2018. Two factors most strongly associated with their receipt were having peripheral intravenous access only (adjusted odds ratio [aOR], 6.15; 95% confidence interval [CI], 4.58-8.26; P < 0.001) and year of admission (aOR, 0.74 per year after 2012; 95% CI, 0.69-0.80; P < 0.001). Other factors that had associations after adjustment included admission to a nonteaching hospital (aOR, 2.19; 95% CI, 1.23-3.89; P = 0.007), admission to a coronary care unit (aOR, 2.56; 95% CI, 1.001-6.54; P = 0.05), Sequential Organ Failure Assessment score (aOR, 0.92 per unit increase; 95% CI, 0.88-0.96; P < 0.001), and heart rate (aOR, 0.92 per 10-beat per minute increase; 95% CI, 0.87-0.97; P = 0.002). Conclusions: In a large cohort of patients in Alberta, Canada, we found a steady decrease in use of first-line vasopressors other than norepinephrine in septic shock. The strongest factor associated with their use was the presence of only peripheral venous access, suggesting that this may still be considered a barrier to administration of norepinephrine.