ICU

Question 1

Features of carbon monoxide poisoning?

Answer 1

CO poisoning:

Headache (most common Sx)
Malaise, nausea, and dizziness.
Loss of consciousness (Hx)
Altered mental status

Acute myocardial injury common.

Delayed neurological sequelae (delayed neuropsychiatric syndrome) feared outcome.

Question 2

Dx of CO poisoning:

Answer 2

Note caveats:

• Sats will be normal (probe measures oxyHb and carboxyHb).
• PaO2 will be normal - CO poisoning is a problem with Hb (high affinity for CO > O2).

ABG:

• Respiratory acidosis
• Often profound metabolic acidosis
• p50 low (ie. LEFT shift in Hb-O2 curve due to Hb’s high affinity for CO).
• CarboxyHb high (definitive).

Note: these ABG findings can be altered by hydroxycobalamin administered for suspected cyanide poisoning after smoke inhalation.

Question 3

Management of CO poisoning?

Answer 3

Management is supportive.

1. High flow oxygen (accelerates displacement of CO from Hb).
2. Hyperbaric oxygen therapy accelerated this process further - therefore used in severe / high risk cases.
3. Isocapnic hyperpnoea if ventilated.