Extracorporeal cardio-pulmonary resuscitation in a patient with missed diagnosis of sodium nitrite intoxication.

Introduction: Critical poisoning with sodium nitrite (NaNO₂) can present challenges in promptly identifying and managing acute methemoglobinemia.

Case report: We report the case of an overt self-intoxication by an initially unknown agent, leading to cardiac arrest. Despite prodromal signs of cyanosis, coma, desaturation, and hypotension, methemoglobinemia went unrecognized during extracorporeal cardiopulmonary resuscitation (ECPR) as the point-of-care test failed to provide methemoglobin levels, leading to untreated methemoglobinemia. The blood flowing through the oxygenator notably maintained the same brown colour. Return of spontaneous circulation was never achieved, and the patient was declared dead after 60 min of unsuccessful resuscitation. Cause of death by means of NaNO₂ voluntary ingestion was later clarified and confirmed by postmortem finding of elevated nitrite and nitrate concentration.

Conclusions: This case highlights the risk of failure of ECPR in the context of cardiac arrest due to methemoglobinemia, emphasizing the critical need for prompt recognition of the causative agent and early administration of antidotes.