Intravenous arginine vasopressin infusion in refractory vasodilatory shock: a clinical study.

OBJECTIVE: To assess the efficacy of arginine vasopressin (AVP) as a rescue therapy in children with catecholamine refractory vasodilatory shock and its effect on various hemodynamic, clinical, and laboratory variables.

METHODS: This prospective hospital based study was conducted from January 2008 through July 2008 at a tertiary pediatric cardiac critical care unit. Twelve post cardiac surgery patients with advanced vasodilatory shock requiring intravenous vasopressin infusion longer than 60 min were included and continuous vasopressin infusion was given. The primary outcome measures were restoration of Mean arterial blood pressure (MAP) after starting AVP infusion and decrease in other concurrent catecholamines requirement. The secondary outcome measures were survival to hospital discharge, adverse effects, and laboratory variables.

RESULTS: Vasopressin was infused in the dose range of 0.0005 to 0.003 units/kg/min for a mean duration of 55.6 h. MAP improved from 41.08  ±  6.15 mmHg at baseline to 48.92  ±  10.05 mmHg after 1 h (P < 0.05), to 57.01  ±  8.30 mmHg after 4 h of AVP infusion (P < 0.001), and to 62.33  ±  8.55 mmHg after 12 h (P < 0.001), which further increased to 71.75  ±  9.55 mmHg after 24 h (P < 0.001). Inotrope score and requirement of other concurrent inotropes declined significantly in all patients after starting AVP infusion (P < 0.001). Lactate levels also declined significantly (P < 0.0001). No significant adverse effect due to end organ ischemia was observed. Only one patient expired while on vasopressin infusion due to refractory hypotension.

CONCLUSIONS: Concurrent addition of vasopressin at an appropriate stage help improving MAP significantly with decreased dependence on high dose catecholamines without any significant adverse effects.