%0 Journal Article %A Rob Hallifax %A Tina O'Hara %A Amulya Misra %T Hypoxic? Don't “pop” to the shops %D 2015 %R 10.1183/13993003.congress-2015.PA3681 %J European Respiratory Journal %P PA3681 %V 46 %N suppl 59 %X Background: Acquired methaemoglobinaemia can be a serious complication of the use of recreational and pharmaceutical drugs. Oxidisation of haemoglobin from ferrous to ferric state results in an inability to bind oxygen. High levels of methaemoglobinaemia can cause significant tissue hypoxia with symptoms: from headache, nausea, tachycardia, to profound hypotension and cardiac arrest.Case Report: This report describes a young man presenting with headache, cyanosis and oxygen saturations of 86% on high flow O2. On blood gas analysis, his methamoglobin level was 66% (normal 0-2%). The patient denied taking regular medications or recreational drugs use. Detective work by the medical team revealed that the patient had mistakenly ingested an isopropyl nitrite (colloquially known as “poppers”) thinking that it was caffeinated “energy drink”. The nitrite ingestion had induced a significant methaemoglobinaemia, which was successfully treated with intravenous methylene blue – reducing the methamoglobin level to 2% within two hours.Discussion: Pulse oximetry is inaccurate in patients with methaemoglobinaemia, as the readings is based on the assumption that only two varieties of haemoglobin are present (oxyhaemoglobin and deoxyhaemoglobin). Commonly, pulse oximetry will give readings of approximately 85%. Previous case reports describe methaemoglobinaemia as a result of intentional inhalation of volatile nitrites or cocaine usage. In this case, a young man inadvertently ingested a toxic substance, inducing methaemoglobinaemia, which was successfully treated. Physicians should be aware of this uncommon clinical scenario in patients presenting with cyanosis or unexplained low oxygen saturations on pulse oximetry, even in the absence of overt recreational drug use. %U