Recognizing and treating methemoglobinemia: a rare but dangerous complication of topical anesthetic or nitrate overdose.

Methemoglobinemia is a rare but dangerous complication of topical anesthetic overdose administration or exposure to nitrate-containing substances in the hospital or community. Paradoxically, although the patient may present with cyanosis with low oxygen saturation levels, they will not respond to oxygen therapy. Treatment is slow intravenous administration of a titrated dose of methylene blue. Adult and pediatric critical care nurses and respiratory therapists, operating room and procedure/diagnostic center nurses, short-stay or outpatient surgery center staff, and adult and pediatric emergency department nurses and respiratory therapists need to be aware of this potentially fatal condition.