Methemoglobinemia: Difference between revisions
(Created page with "==Background== *Methemoglobin refers to ferric form of Hb (Fe3+) that is unable to bind O2 *Caused by exposure to oxidizing agent (benzocaine, CN kit,antimalarials) *Suspect in ...") |
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**1-2mg/kg (approx 7mL) IV over 15min; repeat dose if needed | **1-2mg/kg (approx 7mL) IV over 15min; repeat dose if needed | ||
**Improvement seen w/in 20min | **Improvement seen w/in 20min | ||
==See Also== | |||
[[Toxidromes]] | |||
==Source== | ==Source== |
Revision as of 07:15, 25 February 2012
Background
- Methemoglobin refers to ferric form of Hb (Fe3+) that is unable to bind O2
- Caused by exposure to oxidizing agent (benzocaine, CN kit,antimalarials)
- Suspect in any pt whose cyanosis does not respond to supplemental O2
Clinical Features
- Levels
- Pts with anemia or preexisting cardiopulmonary disease will show symptoms sooner
- <20%: asymptomatic, gray-blue cyanosis
- 20-30%: anxiety, HA, weakness, light-headedness, tachycardia
- 50-60%: myocardial ischemia, dysrhythmias, depressed mental status, seizure
- >70%: incompatible w/ life
Diagnosis
- Co-oximetry
- SpO2 will initially be falsely elevated until MetHb >30% (SpO2 will then fall to 80-85%)
- "Chocolate brown" color of blood
Treatment
- Methylene Blue
- Reserved for symptomatic pts or asymptomatic pts w/ MetHb >25%
- 1-2mg/kg (approx 7mL) IV over 15min; repeat dose if needed
- Improvement seen w/in 20min
See Also
Source
- Tintinalli