A couple posts back Erik Tenkar asked how people would deal with death spirals (assuming they wanted one) in S&W along with other games in comparison to how they happen in Tunnels and Trolls. I commented:
"If you have a death spiral is S&W (and similar games), the monsters
thatbkeep onn fighting into negative HP or berserker like foes shouldn't
have a death spiral, undead shoudn't have one either (as they are dead
already) unless being attacked by holy weapons. Regenerating creatures
shouldn't have one either unless a DM wants to go insane."
Of course about 10 seconds after I hit send I thought some more on the topic and instead of posting more there I figured this was a good place to put the options.
The tunnels and trolls death spiral for monsters is an easy mechanic to track in that game as fighting ability and HP are the same thing really; there are a number of minor variations but essentially when a monster attacks yuo take it's current MR (monster rank which is usually 5 or more points per dungoen level) divide that by 10 and roll as many d10's as you have and add the MR to determine how effective the monster's attacks are. As a fight goes on in T&T the monsters get weaker. Character types suffer damage to their CON stat and as such don't really get weaker until they flop over dead.
Option1, new combat charts: In D&D monsters and player characters have the same mechanics in regard to durability (those good old HP) and how well a character or monster fights is keyed to their level or HD not the HP total. One could of course redo the combat tables to reflect HP totals and that really isn't very hard to track at all and requires no additional record keeping or math than is already used in the game.
Option 2, wound tally: Another way that does require some a little more record keeping but instead of really worrying about HP scores is based on wounds suffered while keeping some significance to level and hit dice. I'd do so by scoring a hit as a wound if it does more damage then the target's level/hitdice and each such wound inflicts a -1 penalty to attack rolls (and possibly saving throws and movement rate). I'd recommend this be a fate suffered by PCs as well with each such wound is removed by an application of healing magic (don't worry about hp per wound afterward, too much to worry about). PCs and monsters could (if they survive a fight) take the time to tend to their wounds, nullifying each one with a full 10 minute turn of nursing their wounds. The ability to nurse wounds gives the PCs a chance at a longer life as they are typically often hit and have a longer table-life than most monsters. I'd likely keep in mind berserkers, undead, and regenerating monsters as in my original comment copied above.