Expert: Floyd's carbon monoxide was in normal range

The prosecution in the Derek Chauvin trial recalled Dr. Martin Tobin, a lung and critical care expert to knock down a defense theory that carbon monoxide poisoning from a squad car's exhaust might have contributed to George Floyd's death. (Apr. 15)

Video Transcript

ERIC NELSON: You're not suggesting to the jury that Mr Floyd died of carbon monoxide poisoning.

DAVID FOWLER: Not exclusively, no.

ERIC NELSON: If you're not saying that carbon monoxide caused Mr Floyd's death, can you likewise eliminate it as a contributing factor?

DAVID FOWLER: The only way to eliminate carbon monoxide as a contributing factor would be to ensure that there was none in his blood, or a very, very low level in his blood, so, in Mr Floyd, it robs him of an additional percentage of oxygen-carrying capacity.

JERRY BLACKWELL: So if we know that there is an oxygen saturation of 98%, does that tell us anything whatsoever--

MARTIN TOBIN: Yes, it can.

JERRY BLACKWELL: --about what--

MARTIN TOBIN: I'm sorry. I interrupted. I apologize.

JERRY BLACKWELL: Does that tell us anything whatsoever about what the carbon monoxide content could have been at a maximum in [INAUDIBLE]?

MARTIN TOBIN: Yes. Yes, it does. It tells us that if-- if the hemoglobin is saturated at 98%, it tells you all there was for everything else is 2%, and so the maximum amount of carbon-- carbon monoxide would be 2%. It tells you the maximum amount of carboxyhemoglobin. That was what was mentioned yesterday. The maximum amount is 2%.

JERRY BLACKWELL: And so in other words as to the statement that his carboxyhemoglobin could have increased by 10 to 18%, in your view, that's not possible.

MARTIN TOBIN: It's simply wrong.

JERRY BLACKWELL: And it was at most 2%.

MARTIN TOBIN: At-- at most 2%.

JERRY BLACKWELL: Normal. Very-- I mean, which is normal.