After looking over the rules for Medicae, both my GMs (yes, plural) and I decided that the system was very unclear and binary, and I came up with the system which we are now using. I'm currently a 60 intellect adept with Medicae of dafuq, so needless to say figuring this system out was important to me. We haven't run into an instance with Unnatural Intelligence being a factor, so we were planning to leave that up to GM's discretion to work that out.
First Aid Medicae Rules:
Using the Medicae skill to perform First Aid offers a quick fix for injured or dying characters. A successful Medicae Test removes Damage based on a combination of you Intelligence Bonus and degrees of success as describe below to Lightly Wounded characters, 1 Damage from Heavily Wounded characters and 1 point of Critical Damage from Critically Wounded characters. 2 Damage is removed if the character using the skill is a Master Churigeon. Characters with Hardy or Autosanguine are always considered Lightly Wounded for the purpose of Medicae. On a failure, the patient is not adversely affected and simply removes Damage at the natural healing rate. However, a failure by three or more degrees indicates that Lightly or Heavily Wounded take a point of Damage, whilst a character on 0 Wounds must make a Toughness Test or die.
The Damage removed from lightly wounded characters follows this formula rounded up:
0 Degrees of Success: 1/3 * Intelligence Bonus.
1 Degrees of Success: .5 * Intelligence Bonus.
2 Degrees of Success: 1 * Intelligence Bonus.
3+ Degrees of Success: 1.5 * Intelligence Bonus.
First Aid may only be applied to each targetable body part once and is a Full Action by you and your patient. It also can only remove damage up to the amount of Damage that body part has taken. Future damage to healed body parts in different combat situations are considered completely seperate, and therefore you can remove damage (remembering that only damage taken that combat to that body part can be removed).
Note: You may only administer first aid to exposed flesh. Damage that is taken to a body part where armor is still full intact and covering the wound may only be administered first aid if the armor is removed. You may also not remove damage for bionic or mechanical body parts.
Example (From Actual Battle):
Arbitrator w/ TB of 4
4 Right Arm
1 Body
After the battle, the Arbitrator is considered lightly wounded as his total wounds are less than double his TB. The Medicae may test for both the Arm and Body, and, if sucessful, may remove damage equal to his Int Bonus from each part up to the damage.
Arbitrator w/ TB of 4
4 Right Arm
5 Body
After the battle, the Arbitrator is considered heavily wounded as his total wounds are greater than double his TB. The Medicae may still test for both the Arm and Body, but only may remove 1 Damage (or 2 Damage for Churigeons) from each.
Notes: For extended care, damage healed is considered to apply to total wounds and not indivual body parts, and broken bones or teared muscles are healed faster as determined by the GM.