I'm not only a DM, I'm also an ER doc (mutch to my players annoyance when I have them theoretically treat tension pneumothoraxes after arrows and such) - so I can't avoid inventing some houserules regarding Hit Points for our next session to give it a more realistic feel, with only small changes to any rules. In short, we will use the 4th edition bloodied-rule in a new way.
A character can lose half of his Hit Points and recover them with just one turn (10 minutes) of rest. If a character loses more than half of his HP, he is Wounded.
The tresholds are:
Half HP left - Minor Wounds.
A quarter of HP left – Moderate Wounds
0 HP left – Critical Wounds and Unconscious.
Negative HP equivalent of level - the character dies (a lvl 3 character dies at -3 HP)
The effect of being Wounded is simply that you cannot heal any HP naturally until your wounds are healed. When they do, you get full HP instantly. Natural healing of Wounded status is:
Minor wounds – 7 days of rest, 3 days if you pay a medicus who uses herbs, surgery and stuff
Moderate wounds – 30 days of rest, 14 days with the medicus
Critical wounds – 6 months, 2 months with medicus
Clerical healing and magic potions work just as stated by the title in the rules, they cure Minor/Moderate/Critical wounds instantly – and therefore all HP if the character also rests for 10 minutes. If one uses a Cure minor wounds on a Moderately Wounded character, the character still heals HP and can be restored to full HP just as in the core rules. He is still Wounded though, and can't heal naturally until he has gotten the bed rest.
To be Wounded does not affect a character in any other way rules-wise, except if the DM wants to use rules for wound infections or other stuff (”the wolves don't notice you and pass, but wait! One of them sniffs in the air...”) It will be encouraged to roleplay wounds though (”I walk down the corridor, no, more shambling, holding my leg to keep the bleeding at bay”).
The philosophy of Hit Points would be that it simulates a characters combat readiness and not only wounds and stamina. Basically they are how far from receiving a killing or crippling blow the character is in a combat. A critically wounded character who has full HP from clerical healing is filled with positive energy and will parry and dodge without feeling his wounds for that actual battle. A lightly wounded brigand without no supernatural healing will probably have half his HP for a long time, being tired and feeling the cuts and bruises, not parrying and holding his guard as well as he did unwounded.
The conditions to describe (but not necessary to write down) for different wounded statuses would be:
Full HP: Ready and well.
HP below maximum but over half : Stress-induced tunnel-vision, excessive sweating and tremor, tiredness in sword-arm, numbness in shield-arm, headache from blows to the helmet, armor straps at loose, general tiredness and panting heavily, sweat and blood in eyes, pain from blows to armour, superficial cuts and bruises etc
Half HP or below (Minor Wounds): Cuts and wounds in need of suturing, bleeding inside big muscles from crushing blows or blows on armour resulting in general stiffness, mild concussions, severe tiredness on verge of collapsing etc
1/4 of HP or below (Moderate Wounds): Deep and large cuts and wounds exposing muscles and inner organs without damaging them too severely, arrows and smaller weapons stuck in body, broken ribs, compartment syndrome from bleeding in muscles resulting in horrible pain, broken bones in hands feet and face etc
0 HP or below (Critical Wounds): Cracked skulls, broken arm- and legbones, bowels hanging out, punctured lung etc. The character is unconscius or in other ways not able to do anything at all, not even speak (may be moaning incoherently and trashing about though).
Negative Lvl HP: Instant death.
The conditions described are supposed to treatable by medical care of fantasy standards without giving permanent injury. If the DM wants, it's free to add lost eyes and fingers, amputated limbs or whatever at the different tresholds.
We have also been thinking about rules for wound infections and death by critical hits.
Wound infecitions: Wounded characters must roll a save vs poison if they move through certain areas or otherwise are exposed to bacteria anf fungi, a fail means -4 to all rolls for 1D6 days, after that a new save vs poison to get well or die. Fever, ganrene etc.
Death by Critical Hits: No character shall be safe in combat with sharp blades, not even a lvl 10 fighter meeting one HD1 orc with a dagger. If an attack roll scores 20, a second attack roll is made. If the second roll also is higher than the AC (meaning attack table number) the character receiving the hit must make a save vs posion (in this case more general stamina) or die instantly. (”You walk up at the orc with your +4 magical golden plate and your sword of Orc Extinction, but the orc lunges at you just as you slip on a puddle and plunges down his rusty dagger through the gaps in your visor. You start to scream when you feel the dagger penetrating your eye-bulb, but your screams stop when he presses it through and into your brain").
We are not sure if we are going to use the last rule, LL is deadly enough at it is. However, it would go both ways, no dragon is safe from a lvl 1 adventurer either. (If AC is so good the attack roll has to be over 20, a double 20 and then roll over attack table number minus 20 might still make it to that save at least).