Methaemoglobin is a form of haemoglobin with oxidised ferric (+3) iron rather than ferrous (+2) iron, which causes a leftward shift in the oxyhaemoglobin dissociation curve and prevents oxygen delivery. Anaesthesiologists need to be familiar with this differential diagnosis for hypoxia given the use of drugs in the perioperative setting known to induce methaemoglobinaemia, including benzocaine and lidocaine, antibiotics such as dapsone and anaesthetic gases, including nitric oxide. This case report details an interesting case of symptomatic methaemoglobinaemia in the perioperative period in the setting of dapsone use and an erector spinae block performed with ropivacaine.
- haematology (drugs and medicines)
- unwanted effects / adverse reactions
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Contributors AC: wrote the initial draft of the patient presentation, edited and submitted the final draft. SG, SK and PS: served as the mentor for this project and helped with draft editing.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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