The Vasopressin Loading for Refractory septic shock (VALOR) study: a prospective observational study

Area of Science:

• Critical Care Medicine
• Pharmacology
• Hemodynamics

Background:

• Vasopressin is a second-line agent for refractory septic shock.
• Vasopressin loading is not routinely used due to limited evidence on its effects and safety.
• Previous research suggests potential benefits and safety of vasopressin loading.

Purpose of the Study:

• To prospectively examine the safety and efficacy of vasopressin loading in predicting response to continuous vasopressin infusion in septic shock.
• To establish vasopressin loading as a tool for patient stratification and treatment selection.

Main Methods:

• Vasopressin loading (1 U bolus followed by 1 U/h infusion) was administered to patients with septic shock receiving noradrenaline.
• Arterial pressure wave analysis and endocrinological tests were performed before loading.
• Patients were classified as responders or non-responders based on mean arterial pressure (MAP) changes post-loading.
• The primary outcome was the change in catecholamine index (CAI) after 6 hours; adverse events included ischemia.

Main Results:

• Ninety-two patients were included; 62 were responders (MAP change > 22 mmHg).
• Responders showed higher stroke volume variations pre-loading and higher stroke volume and dP/dtmax post-loading.
• Median CAI change was significantly lower in responders (-10) compared to non-responders (0) (p < 0.0001).
• MAP change after vasopressin loading predicted a CAI change < 0 with high accuracy (AUROC 0.843, sensitivity 0.92, specificity 0.77).
• Adverse ischemic events occurred in 5.4% of patients.

Conclusions:

• Vasopressin loading appears to be a safe and effective method in managing septic shock.
• This loading strategy can predict patient response to continuous vasopressin infusion.
• Vasopressin loading facilitates the selection of appropriate blood pressure management strategies.