Phenotype-driven use of vasopressin in distributive shock: results of a national consensus

Distributive shock is a major cause of haemodynamic instability in critically ill and perioperative patients. Despite norepinephrine being the recommended primary treatment, its adverse effects, which are dose-dependent and include arrhythmias and myocardial ischaemia, along with catecholamine resistance, support the consideration of additional non-adrenergic approaches. Growing evidence suggests that vasopressin can restore vascular tone through non-adrenergic pathways, reduce catecholamine exposure, and potentially enhance organ function, although uncertainties remain regarding optimal timing, patient selection, and practical implementation. This Italian national consensus aimed to provide phenotype-driven, bedside-applicable guidance on the practical use of vasopressin in vasodilatory shock, with an emphasis on haemodynamic stabilisation, catecholamine sparing, and organ protection. Using a modified RAND/UCLA appropriateness method, a multidisciplinary panel of intensivists and anaesthesiologists evaluated six clinical phenotypes: overwhelming septic shock, septic shock with tachycardia/tachyarrhythmia, septic shock with acute kidney injury, post-cardiac surgery refractory vasoplegia, persistent post-reperfusion shock during liver transplantation, and shock in severe ARDS with right ventricular dysfunction. Each scenario was explored using real-world composite vignettes to enhance bedside applicability. Across phenotypes, early adjunctive low-dose vasopressin was rated as appropriate, often at norepinephrine base doses of approximately 0.2 μg/kg/min, and as early as 0.1–0.2 μg/kg/min when tachyarrhythmia risk is prominent. In post-cardiac surgery refractory vasoplegia, vasopressin was rated as appropriate to restore vascular tone and reduce catecholamine toxicity, whereas the strategy of tapering vasopressin before norepinephrine was uncertain due to disagreement. Vasopressin was also rated as first-line support in severe ARDS to maintain vascular tone without increasing pulmonary vascular resistance. The consensus integrates evidence suggesting catecholamine-sparing effects, lower atrial fibrillation risk, and possible reductions in renal replacement therapy, while highlighting safety considerations and key evidence gaps regarding the optimal triggers, phenotype-specific effects, and long-term outcomes. This study offers practical guidance for integrating vasopressin into a customised vasopressor strategy and outlines the priorities for future research in precision haemodynamic management.