Ok so, take this with a BIG grain of salt, because I may be a medical doctor BUT you need to know how much wound care training we get in medical school: none. Zip. Zilch. There may be medical schools where you do, but mine wasn't a bozo factory and there was NO wound care training. Everything I know I learned from one of several sources: an intensive 2-day wound care course I did in residency (highly recommend), the local Home Health wound care nurse (highly recommend), a completely batshit insane old white male doctor who started our learning sessions by yelling Vietnam War stories at me (do not recommend), a hospital wound care nurse (highly recommend), and experience (oh god do not recommend).
The first thing you need to know is that wound healing varies dramatically across the course of a lifespan. Kids? Kids will heal. If they don't, get their ass to a pediatrician because there's something genetic going on. Young adults will heal. Middle-aged adults will heal. You know who doesn't heal for shit? The elderly, and people with severe illnesses, and people with uncontrolled type II diabetes.
Your body needs several things in order to heal. It needs macronutrients, so you need to be able to EAT protein, fat, and carbs. If you are on total parenteral nutrition, aka TPN, aka IV nutrition, you are going to be worse at healing. If you are starving yourself, you are going to be worse at healing. If your body is desperately funneling all the calories you take in to surviving your COPD or cancer, you are going to be worse at healing.
It also needs micronutrients. If your diet sucks, you won't heal. Take a multivitamin once in a while.
There are two CRITICAL skin components to healing: collagen and elastin. Guess what we stop making as we age. Promoting collagen isn't just good for "anti-aging," it's good for NOT ripping your skin apart. Taking oral collagen is probably bullshit because your body is going to have to disassemble it to get it across the intestinal membranes to absorb, but it's also harmless, and if your diet REALLY sucks, who knows. Give it a try. Collagen is made of amino acids; think protein.
Another absolutely crucial component is blood flow. As people age, they start to develop cholesterol plaques lining arteries that eventually pick up calcium deposits. This makes blood vessels less elastic, which is a problem, but eventually also blocks them off, which is a much bigger problem. If someone has the major blood flow to their feet decreased by 90% by arterial stenosis, they are not going to heal for shit AND their foot's gonna hurt.
One component of blood flow I hadn't thought about before going into medicine is fluid retention. The way your body works, blood exits the heart at a very high velocity, but slows to a crawl by the time it gets into capillaries, the smallest blood vessels in the body. Water is a very small molecule and can leave the blood vessel, especially if there aren't big, negatively-charged molecules like proteins like albumin in the blood vessels to hold the water there. And we're built for this--some water is supposed to leak out of our blood vessels when it gets to real little vessels. It gets taken back up by the lymphatic system and eventually dumped back into the bloodstream at the inferior vena cava. But if you aren't making albumin--for instance, in liver failure--you may leak a LOT of fluid into the tissue, so much that your legs get swollen, tight, the skin feeling woody and strange. This isn't fixable by drainage because the fluid is everywhere, not in a single pocket we can drain. And because it puts so much pressure on the tissues of the skin, it often results in ulcers. Congestive heart failure, liver failure, kidney failure--these are all common causes of severe edema, aka swelling due to fluid in the tissues. And they're a real bitch when it comes to wound care, because we have such limited resources for getting the fluid back out, which is a necessary first step to healing.
Pressure is another common cause of wounds. Pressure forces blood out of those little capillaries, so you starve the cells normally fed by those capillaries, and they die. It's called pressure necrosis. Very sick people who can't turn themselves over--people in the ICU, people in nursing homes--are especially prone to these wounds, as are people with limited sensation; pressure wounds are common in wheelchair users who have lost some feeling in the parts of their bodies that rub against those surfaces, or diabetics who don't notice a rock in their shoe.
So, if you're trying to treat wounds, the questions to ask are these:
Why did this wound happen?
-Was it pressure? If it's pressure, you have to offload the source of the pressure or else that wound will not heal. End of story. You can put the tears of a unicorn on that thing, if you don't offload the pressure it won't heal.
-Was it fluid? If it's fluid, you have get the fluid out of the issues or else it won't heal. You can sometimes do that with diuretics, medications that cause the body to dump water through the kidneys, but that's always threading a needle because you have to get someone to a state where they still have juuuuust enough fluid inside their blood vessels to keep their organs happy, while maintaining a very slight state of dehydration so the blood vessels suck water back in from the tissues. You can use compression stockings to squeeze fluid back into the vessels, but if they have arterial insufficiency and not just venous insufficiency, you can accidentally then cause pressure injury. The safest option is using gravity: prop the feet up above the level of the heart, wherever the heart is at, at that moment, and gravity will pull fluid back down out of the legs. Super boring though. Patients hate it. Not as much as they hate compression stockings.
-Was it a skin tear because the skin is very fragile? This is extremely common in the elderly, because they're not making collagen and elastin, necessary to repairing skin. If this is the case, make sure they're actually getting enough nutrition--as people get into their 80s and 90s, their appetites often change and diminish, especially if they're struggling with dementia. And think about just wrapping them in bubble wrap. Remove things with sharp edges from their environments. I have seen the WORST skin tears from solid wood or metal furniture with sharp edges. Get rid of throw rugs and other tripping hazards. I had somebody last week who tried to a clear a baby gate and damn near destroyed their artificial hip.
The next critical question: why isn't it healing?
-Are you getting enough nutrients? Both macro and micro?
-Do you have a genetic disorder of collagen formation?
Fix why it's not healing and almost anything will heal. If you're diabetic, find a medication regimen that improves your sugars and stick to it. If you're anorexic, get treatment for your eating disorder. If you have congestive heart failure, work with your doctor on your fluid balance. Wear the damn pressure stockings. Prop up your feet.
If, after those two unskippable questions are done, you want to do something to the wound--apply a dressing, do a treatment--that's a whole other kettle of fish. I'll write that later. The dryer just sang me its little song and I need to put away the laundry.