I think the "near-future" future requirement hurts this possibility. We don't know how to treat a lot of the things the bacta tank addresses to begin with even using the full extent of modern medicine.
Here are some techniques that at least have a basis in current research (ie no super nanobots):
* There are a few proteins that aid the body's natural tissue healing process in mammals: for instance MG53 and thrombospondin 2. The tank could contain bacteria that produce versions of these proteins altered to be more effective, as well as a soup of simple sugars to fuel the bacteria's production. Proteins that require energized ATP to function could be supplied by a different strain of bacteria. These proteins have been shown to accelerate healing and remove scars in mice; there's probably a good analog in humans.
* The mixture could be programmed to the genotype of the person submerged in it by a medical technician. 225
Engineered stem cells float in the fluid until they find a spot including inflammation. They then specialize to become skin cells or immune system T-cells, aiding in closing wounds and fighting infection.
* The mixture could contain topical antibiotics (if there are bacteria in it as well they need to have antibiotic resistance)
* The mixture contain cells that produce bacteriophages to target foreign bacteria that they find. This is more precise than antibiotics and has fewer side effects
* The temperature of the fluid can be controlled to help the body regulate internal temperature, and the fluid can be made to conduct heat very well to speed up this process.
* The fluid can contain Chemical Permeation Enhancers to make the skin more permeable, allowing introduction of water and various anti-inflammatory or analgesic drugs.
* The fluid can contain topical antivenins to counteract snake/insect bites, poison ivy/nettle burns, or even biological/chemical weapons.
* You can breathe a higher concentration or pressure of oxygen through a tube, allowing for accelerated healing and reduction of pain, inflammation and headaches.
The main thing with these though is that they only target the outside of the body. What if you have internal bleeding or broken bones?
The fundamental problem here is that if you have a fluid that can fix internal damage, the ideal method of delivery for it is not "dunk the patient in a big vat full of medicine until they get better." The fluid would have to enter the body at some point in order to function, and I don't see how it's going to do that.
You could probably treat a good number of conditions with a relatively near-future bacta tank:
* Burns
* Scarring
* Cuts & abrasions
* Topical infections
* Skin fungus
* Hypothermia
* Hyperthermia (overheating, usually due to fever)
* Rash or inflammation
* Snakebites/insect bites/poisonous space monster bites
* Dehydration
* Headaches
* Sleep deprivation (because hey, you're floating in a tank for hours)
Things it won't treat (not a complete list for obvious reasons):
* Broken bones
* Ruptured organs
* Brain damage
* Cancer
* Pneumonia (if you're having lung trouble breathing through a tube could cause problems)
* Radiation poisoning
* Food poisoning
* Pretty much any other type of poisoning
* Genetic diseases
* Psychological conditions
* Claustrophobia (duh)
* Fear of drowning (duh)
* Anaphylactic shock
* Ordinary shock
* Blood loss (it won't treat this without some other equipment providing blood)
* Hair loss
* Heart disease
* Diabetes
* Obesity
* Bruises or internal bleeding
* Shrapnel damage
* Missing limbs
* Missing organs
* Blindness
* Deafness
...You get the picture. It's not a panacea, but it is a valuable piece of medical equipment. 225