Carbon monoxide
gas transfer
- high affinity for Hb
- transfer is diffusion limited
Toxicity
| Think about co-habitants | |
|---|---|
| Etiology | Common history: car exhaust, incomplete combustion in charcoal burners, faulty heaters, fires, industrial accidents, methylene chloride Chronic exposure can look like dementia, psychosis, ataxia, Parkinsonism |
| Clinical presentation | Non-specific - headache, confusion, weakness... WITHOUT fever Cohabitants (including animals!) simultaneously unwell COHb >50% → ECG changes, seizures, coma |
| Toxokinetics | t½ 4-5h - eliminated from lungs |
| Pathogenesis | ↓ availability of Hb (see above); direct effect on cytochrome oxidase |
| Diagnostic investigations | Smokers may have COHb up to 10% ABG: metab acidosis, ↑ lactate |
| Management | fiO2 100%, hyperbaric oxygen - ↓ t½ to 30 min Check for and treat cyanide toxicity e.g. housefire In pregnancy - often causes foetal death |
sources/links
https://litfl.com/carbon-monoxide-poisoning/
https://emcrit.org/ibcc/co/
https://derangedphysiology.com/main/cicm-primary-exam/acid-base-physiology/Chapter-814/lactic-acidosis-due-carbon-monoxide-poisoning
https://derangedphysiology.com/main/cicm-primary-exam/respiratory-system/Chapter-126/spectrophotometry-carboxyhaemoglobin