(1490) Vasopressin Initiation as a Second-Line Vasopressor in Early Septic Shock

Introduction: Vasopressin is recommended as a second-line vasoactive agent for the management of septic shock; however, a paucity of data to guide its optimal use remains. The aim of this study was to evaluate the effect of time-to-vasopressin initiation and norepinephrine (NE) dose at vasopressin initiation on clinical outcomes in patients presenting with septic shock.

Methods: This was a multi-centered, retrospective, observational study conducted in patients with septic shock. Patients were divided into 2 groups: patients initiated on vasopressin when NE-equivalent dose (NEE) < 0.25 mcg/kg/min or ≥ 0.25 mcg/kg/min. The primary outcome was time-to-vasopressor discontinuation (hours). Secondary outcomes included 28-day in-hospital mortality, intensive care unit (ICU) length of stay (LOS), fluid balance after 72 hours, and the change in NEE at 12 hours. Propensity score matching was conducted to reduce confounding impact on the primary outcome. Furthermore, a multivariable linear regression was used to analyze the primary outcome.

Results: A total of 302 patients were included in this study. After propensity-score matching, 73 patients in each group were identified for analysis. There was no significant difference in the time-to-vasopressor discontinuation (hours) between the groups (88.8 [55-187.5] vs 86.7 [47-172]); p=0.7815). There were no differences in secondary outcomes except for fluid balance (mL) at 72 hours which was significantly lower when vasopressin was initiated at NEE < 0.25 mcg/kg/min (1769 [71-7287] vs 5762 [1463-8813]; p=0.0077). Furthermore, a multivariable linear regression showed shorter time to shock resolution with earlier vasopressin initiation, defined as within 4 hours (p < 0.05).

Conclusions: In this propensity-score matched cohort, vasopressin initiation at NEE < 0.25 mcg/kg/min was not associated with shorter vasopressor duration. There was a lower fluid balance at 72 hours when vasopressin was initiated at lower NE doses.