Green’s Dictionary of Slang

d.o.a. v.

[orig. police jargon d.o.a. adj., dead on arrival]

to die before one arrives at a hospital.

[[UK]C. Fluck ‘Bubbles’ of the Old Kent Road 25: Poor lass; D.O.A. – Dead on Arrival].
[US]N. De Mille Smack Man (1991) 109: If I had my way all you worthless hoors could DOA.