Successful use of methylene blue following out of hospital cardiac arrest: a case report

Background: Cardiac arrest and cardiogenic shock are medical emergencies with poor survival rates despite improvements in advanced life support and resuscitation techniques. Case summary: We present the case of a 44-year-old woman with ischaemic cardiomyopathy who suffered a prolonged out-of-hospital cardiac arrest due to ventricular tachycardia. Despite high-dose catecholamines and vasopressin, the patient had persistent hypotension and elevated vasoactive-inotropic requirements. Haemodynamic monitoring revealed features consistent with post-arrest vasoplegia. Two low-dose boluses of methylene blue (0.25 mg/kg) were administered, resulting in a rapid and sustained improvement in cardiac output, index, and blood pressure, alongside a marked reduction in vasoactive support. The patient made a full neurological recovery and was discharged home. Discussion: While already established in vasopressor resistant septic shock and post-cardiopulmonary bypass vasoplegia, this case highlights the potential role of methylene blue as an adjunct therapy in post out of hospital cardiac arrest vasoplegia, particularly when conventional therapies fail. The dose of methylene blue used was substantially lower than that reported in prior studies of sepsis and cardiac surgery. Further studies are warranted to define the timing, dosing, and clinical impact of methylene blue in this setting.