Comparative Effectiveness of Second Vasoactive Agents in Septic Shock Refractory to Norepinephrine

Objective: We aim to identify the appropriate vasoactive agent in patients with septic shock who are refractory to optimal doses of norepinephrine. Methods: In this retrospective observational cohort study over a 4-year period, patients who received norepinephrine within 24 hours of ICU admission and a second agent within 48 hours were enrolled. Results: Among 2640 patients screened, 234 patients were enrolled, aged 60.8 ± 17.8 years, Acute Physiology and Chronic Health Evaluation IV 98.3 ± 27.5, 81.6% mechanically ventilated, and 65.8% in-hospital mortality. Within 96 hours, 2.8 ± 1.0 vasoactive agents were administered. Fifty, 50, 66, and 68 patients received dobutamine, dopamine, phenylephrine, and vasopressin as the second agent, with crude in-hospital mortality 40.0%, 66.0%, 74.2%, and 76.5%, respectively, P <.001. Survival analysis showed a statistically significant difference in survival time by second vasoactive agent, P <.001. After adjusting for confounding variables, dobutamine showed significant decreased odds ratio (OR) for mortality compared to vasopressin: OR 0.34 (95% confidence interval 0.14-0.84, P =.04). The relative risk of dying was 55.8% lower in patients receiving dobutamine versus vasopressin, P <.01. Conclusion: Dobutamine is associated with decreased mortality compared to other second vasoactive agents in septic shock when norepinephrine is not sufficient. A prospective randomized trial examining the outcome impact of the second vasoactive agent is needed.