Methylene blue for the management of pediatric patients with vasoplegic syndrome

Background Vasoplegic syndrome is a form of vasodilatory shock that can occur after cardiopulmonary bypass. Although norepinephrine is sufficient in most cases to restore adequate systemic vascular resistance and support systemic pressures, vasoplegia refractory to norepinephrine has been reported and is associated with high morbidity and mortality, especially in pediatric patients. The guanylate cyclase inhibitor methylene blue infusion could be a promising therapy for such cases. We reported in this study the response of pediatric cardiac patients with norepinephrine-refractory vasoplegic syndrome to methylene blue infusion. Patient and methods A total of 20 pediatric patients mean age 21.60 ± 9.88 months and mean weight 11.70 ± 3.63 kg, with norepinephrine-refractory vasoplegia after cardiopulmonary bypass were treated with an intravenous infusion of methylene blue (1.5 mg/kg) over 20 min. The effects on hemodynamic parameters, cardiac index, systemic vascular resistance index, and norepinephrine dosage were assessed 1 h after infusion. Results The mean arterial pressure increased significantly, with a mean difference of 16.70 ± 4.88 mmHg; also, a significant increase in systemic vascular resistance (P < 0.001), normalization of cardiac output, and a significant decrease in norepinephrine dosage (from 0.57 ± 0.05 to 0.11 ± 0.13 μg/kg/min) were observed in all patients within 1 h. No adverse effects related to methylene blue infusion were observed. ConclusionA single-dose methylene blue infusion appears to be a promising treatment for norepinepherine-refractory vasoplegia after cardiopulmonary bypass during pediatric cardiac surgery.