CO poisoning Flashcards
Describe CO.
odorless, tasteless, colorless, nonirritating gas formed by hydrocarbon combustion
atmospheric CO is < 0.001%
What is the physiology with CO inhalation?
CO binds to Hb with much greater affinity than O2, forming carboxyhemoglobin (COHb) –> impaired oxygen transport and utilization
What are the sources of CO poisoning?
- Smoke from fires
- Faulty heating system
- Poor ventilation for heating devices
- Cars operating in poorly ventilated areas
How does the oxygenation curve shift with CO poisoning?
Left - diminished ability of the other 3 oxygen sites in Hb to offload oxygen to tissues
What are the clinical features of CO poisoning?
- Headache
- Dizziness
- Malaise
- Nausea
- Confusion
- SOB
- Visual changes
How do you diagnose CO poisoning?
- May be informed of high CO levels by fire department at site of fire
OR - COHb blood levels (venous) - >3% in non-smokers, >10% in smokers
What other investigations should be done in CO poisoning?
- ECG
- Troponin/BNP
- ABG/VBG
- FBS
- Urinalysis
- CXR
What is the management of CO poisoning?
- ABCDE approach
- High flow oxygen via nonrebreathing mask
- +/- hydroxycobalamin - to treat co-existent cyanide poisoning
- +/- hyperbaric oxygen therapy - if very high COHb or LOC, severe metabolic acidosis
What are the long term complications of CO poisoning?
- neurocognitive impairment from hypoxic-ischaemic brain injury
- myocardial injury may predispose to CVD mortality