Sunday November 4, 2007
Do not treat acidosis aggressively in CO poisoning

Non-invasive Pulse-ox is not reliable in CO poisoing and 100% NRM should be applied ASAP in any suspected CO poisoning irrespective of pulse-ox on monitor. CO has high affinity for Hemoglobin (HB) - forming HbCO and it absorbs light almost identically to that of oxyhemoglobin, making pulse-ox very unreliable. 100% Oxygen delivery displaces CO from Hb and decrease its half life from 4.5 hours to 1 hour.

But the most unknown point in CO poisoning management is to not to treat acidosis very aggressively and PH of even 7.15 is acceptable for 2 reasons:

1. Acidosis is good in CO poisoning ! , as it causes rightward shift in the oxyhemoglobin dissociation curve, increasing tissue oxygen availability (Bohr effect).

2. Simultaneously, acidosis improves progressively by itself with 100% oxygen therapy and over treatment may push patient later into severe alkalosis.



Related previous pearl:

Hyperbaric oxygen in CO poisoning

The Bohr Effect and Permissive Hypercapnia