See my post. Using a passive leg raise does shift venous blood from both the legs and the splanchnic bed toward the central circulation, but this was generally a thing for hypovolemic shock (hence the comparison to transfusion, which otherwise seems odd to measure for a non-traumatic cardiac arrest), but generally discredited, even for that, 20+ years ago.

Most arrest patients are primary arrhythmic or hypoxic - there's not a volume issue.

Defib. Compressions. 911. No more, no less.

Is your patient conscious, pulsatile with suspected non-traumatic hypovolemia or vasovagal syncope? Then try a PLR. If not, or you stare blankly at those words, don't.

(Retired paramedic of 14 years.)