In the B/X Moldvay rules reaching 0 hit points means your character died. For our B/X campaign on Twitch and YouTube, we wanted a little extra survivability. For the sake of the stream, so we were not constantly rerolling characters. The game is played on Roll20 so we created a table by modifying the Lingering Injuries table in the D&D 5E Dungeon Master’s Guide.
If a PC is reduced to zero hit points we now roll on the table below for the effect. Roll20 allows us to weight outcomes more than others. For example, we weighted the Minor Scar effect and the Mortal Wound effect by 5. This means these items appear 5 times on the table where the others appear once.