(1493) Comparison of Early Versus Late Vasopressin Initiation in Septic Shock

Introduction: Surviving Sepsis 2021 guidelines recommend norepinephrine (NE) as first line and vasopressin (AVP) as a second-line adjunct to improve organ perfusion. Earlier initiation of AVP to NE may increase efficacy and effect of NE.

Methods: A single center, retrospective observational study evaluating AVP on NE efficacy and titration. Patients aged 18 and above with ICD diagnosis of septic shock admitted to the ICU between 2021 and 2022 were screened. Patients who were pregnant or died within 48 hours of ICU admission were excluded. Patients were split into two groups based on NE dose when AVP was initiated: NE < 20 mcg/min (early vasopressin) versus > 20 mcg/min (late vasopressin). Medical records were reviewed for the range of NE dose reduction, categorized in increments of 1-4 mcg/min versus 5-10 mcg/min, within 6 hours of AVP initiation. Hemodynamic response to AVP was defined as reduction in NE dose and MAP > 65 mmHg 6 hours after AVP initiation. Charts were also reviewed for administration of concomitant medications (steroids, midodrine, angiotensin II) and average ICU and hospital lengths of stay (LOS).

Results: A total of 100 patients from 2021 to 2022 met inclusion criteria. Patients in the early and late vasopressin groups had similar levels of disease severity, based on APACHE II (25.4 and 26.7, respectively) and SOFA (8.1 and 8.9, respectively) scores, with similar lactate level elevations (4.17 and 5.0 mmol/L, respectively). The mean NE dose was 12.8 mcg/min in the early vasopressin group versus a mean of 26.5 mcg/min in the late vasopressin group. In the late vasopressin group, 47.4% of patients required NE titration up to or above original starting dose within 6 hours of AVP initiation. In contrast, 34.9% patients required up-titration of NE in the early vasopressin group. The average ICU and hospital LOS were 7.7 and 16.5 days in the early group versus 8.6 and 18.6 days in the late group.

Conclusions: This data suggests that early initiation of AVP at NE doses < 20 mcg/min is associated with reduced incidence of NE up-titration while maintaining similar hemodynamic response, as well as shorter ICU and hospital LOS. Large, prospective, randomized trials are needed to identify specific doses of NE at which AVP initiation is most optimal.