(1038) Impact of Norepinephrine Dose at Time of Vasopressin Initiation in Clinical Outcomes of Septic Shock

Introduction: The 2021 update of the Surviving Sepsis Campaign Guidelines continues to recommend norepinephrine as the first-line agent for septic shock. However, vasopressin has emerged as the preferred adjunctive agent over other vasopressors, supported by moderate quality evidence and a weak recommendation. The updated guidelines suggest considering vasopressin when norepinephrine dosing reaches 0.25mcg/kg/minute to 0.5mcg/kg/minute, although this recommendation is weak due to inconclusive literature regarding mortality differences based on vasopressin timing.

Methods: This single-centered study was a retrospective chart review conducted at a level-1 trauma community teaching hospital. The study evaluated adult patients admitted to the intensive care unit (ICU) and screened for the presence of septic shock between January 1st, 2019 to July 1st, 2023. Patients within the study were classified as either “early initiation” (≤0.25 mcg/kg/minute ) or “late initiation” (>0.25 mcg/kg/minute) of vasopressin with respect to norepinephrine dosing. The primary endpoint was mortality rate 28-days following vasopressin initiation.

Results: 245 patients were included in the study, with 190 patients receiving late vasopressin initiation. There was no statistically significant difference in the primary outcome when assessing for 28-day mortality between patients who received early versus late vasopressin initiation (49.3% vs. 59.8% respectively, p=0.21). Patients who received early vasopressin initiation were less likely to require renal replacement therapy (40.0% vs. 49.4%, p=0.11) alongside additional vasopressors (38.1% vs. 47.3%, p=0.09). There was no statistically significant difference observed in ICU length of stay, alongside duration on mechanical ventilation.

Conclusions: There was no statistically significant difference found in mortality between those who received early versus late initiation of vasopressin. However, this may be limited to small population size in the early initiation group. There may be a benefit in renal outcomes, alongside the requirement for additional vasopressors in those who receive early-timing vasopressin. Further literature should be conducted with greater population sizes to determine if there is a true benefit in mortality with early timing of vasopressin.