u/I_DRINK_URINE

I'm not a pathologist or medical professional, but I'm hoping someone can answer a question for me.

I was reading a report on a plane crash that happened in Canada in 1978. It contains an unusual amount of detail on the autopsy findings for the pilots. One sentence stood out to me:

"The post mortem tissue lactate profile indicated that this pilot had an acute stress reaction for approximately the last 20 seconds before impact."

There's a similar statement about the other pilot, except it says "10 to 11 seconds". They're on pages 18-19 of the pdf.

I was surprised to see this since I had no idea it was possible to measure something like that. I tried googling and couldn't find any information about how this works, or any other mentions of it being used.

Is this something that really exists or is it some old, discredited technique? I find it hard to believe that it's possible to make determinations like that with that level of precision, especially since I can't find any other mention of it online.