Many years ago, back in the 90s, I melded Wound levels and Health Points together. I used it in my fantasy game long before D6 Fantasy ever came out. I got the idea from the "D6 System" cookbook. Worked like a charm for years of playing with multiple people!
Basically the Health Points were calculated and kept track of. When a character was hit, they roll Constitution+armor to resist the damage. If any damage exceeded the resistance, the difference was subtracted from the Health Point total.
If the character lost from 1 to 10% of their Health, they were considered "Scratched", meaning they suffered -1D penalty for the rest of the round and the next round, then back to normal results.
From 11% to 25% of Health lost, the character was "Wounded". -1D to all but resistance rolls until healed.
From 26% to 50% of Health lost was "Wounded Twice". -2D to all rolls but resistance until healed.
From 51- 75% of Health lost was "Incapacitated". Person had to make a roll to avoid being knocked unconscious, was certainly knocked prone, and was at -3D to all rolls until healed
From 76 to 100% of Health lost was "Mortally Wounded". Character was knocked unconscious for amount of time, and when regain consciousness, was at -4D to all rolls until healed and would lose 1 Health point each round until either they passed away or were healed enough to be out of "Mortally Wounded" category.
More than 100% of Health lost and the character was Dead.