Predictors of response to fixed-dose vasopressin in adult patients with septic shock

Background: Vasopressin is often utilized for hemodynamic support in patients with septic shock. However, the most appropriate patient to initiate therapy in is unknown. This study was conducted to determine factors associated with hemodynamic response to fixed-dose vasopressin in patients with septic shock.

Methods: Single-center, retrospective cohort of patients receiving fixed-dose vasopressin for septic shock for at least 6 h with concomitant catecholamines in the medical, surgical, or neurosciences intensive care unit (ICU) at a tertiary care center. Patients were classified as responders or non-responders to fixed-dose vasopressin. Response was defined as a decrease in catecholamine dose requirements and achievement of mean arterial pressure ≥ 65 mmHg at 6 h after initiation of vasopressin.

Results: A total of 938 patients were included: 426 responders (45%), 512 non-responders (55%). Responders had lower rates of in-hospital (57 vs. 72%; P < 0.001) and ICU mortality (50 vs. 68%; P < 0.001), and increased ICU-free days at day 14 and hospital-free days at day 28 (2.3 ± 3.8 vs. 1.6 ± 3.3; P < 0.001 and 4.2 ± 7.2 vs. 2.8 ± 6.0; P < 0.001, respectively). On multivariable analysis, non-medical ICU location was associated with increased response odds (OR 1.70; P = 0.0049) and lactate at vasopressin initiation was associated with decreased response odds (OR 0.93; P = 0.0003). Factors not associated with response included APACHE III score, SOFA score, corticosteroid use, and catecholamine dose.

Conclusion: In this evaluation, 45% responded to the addition of vasopressin with improved outcomes compared to non-responders. The only factors found to be associated with vasopressin response were ICU location and lactate concentration.