The Drug-Induced Respiratory Disease Website
See also under XIVa-b-e. Cyanosis is slate-greay rather that purple. SpO2 is low or spurious/erratic. Cyanosis is resistant to oxygen therapy. SpO2 low or spurious. PaO2 measured by the Clarke electrode is normal. The hallmarks of methemoglobinemia. Diagnosis is confirmed by chocolate-brown color of blood; which does not turn bright red when bubbled with O2 and/or by spectrophotometric measurement of blood methemoglobin (normally <2%). Four-wavelength pulse CO-oxymetry can also measure methemoglobin and COHb. Methemoglobinemia can be life-threatening or fatal if >40%. Treatment is with oxygen and methylene blue. Severe cases may require HBO or exchange transfusion. Oxidant-induced hemolytic anemia can be found in association
Publications
An Uncommon Complication With Use of Topical Local Anesthetic Agents: Methemoglobinemia.
American journal of therapeutics 2016 Nov/Dec;23;e1968-e1969 — 2016 Nov/Dec — e1968-e1969
Benzocaine and lidocaine induced methemoglobinemia after bronchoscopy: a case report.
Journal of medical case reports 2008 Jan 23;2;16 — 2008 Jan 23 — 16
Benzocaine-induced methemoglobinemia based on the Mayo Clinic experience from 28 478 transesophageal echocardiograms: incidence, outcomes, and predisposing factors.
Archives of internal medicine 2007 Oct 08;167;1977-82 — 2007 Oct 08 — 1977-82
Topical benzocaine (Hurricaine) induced methemoglobinemia during endoscopic procedures in gastric bypass patients.
Obesity surgery 2005 Apr;15;584-90 — 2005 Apr — 584-90
Severe methemoglobinemia after transesophageal echocardiography.
American journal of therapeutics 2003 May-Jun;10;225-7 — 2003 May-Jun — 225-7