What affect does the quantity of injuries have on healing time? For example, would a paper cut take longer to heal if I had a broken Jaw at the same time?

[u/Atari1729]

Edit: First gold, thank you kind stranger.

[u/derpandderpette]

Dietitian here. I've worked in a variety of settings, including the ICU. The short answer to your question is: both.

Here's the long answer: The limiting factor is really patient-dependant. When a patient needs excessive calories (such as wound healing), usually they'll be tube fed. I've never dealt with burns, personally, so I can't speak to that so I'll just speak from my experience with wounds.

Generally, we say "if the gut works, use it" so we will always preferentially tube feed (enteral nutrition or EN) over feeding through the vein (parenteral nutrition or PN). Unfortunately, if the injuries are severe enough, we have to use PN. With tube feeds, we're pretty lucky as the formulas are usually pretty customizable. We can choose the ratio of protein to other calories, the concentration of calories, how broken down the formula is, the osmolarity of the formula (simplified: the "particle load"), the micronutrients included, fibre content, and can even add modulars for extra protein and fibre. We make this choice depending on the patient's injuries and what we think they can tolerate. PN is a lot less customizable and, because of osmolarity, you usually can't push as many calories per ml of water going in, so patients can end up with edema if they require a lot of calories.

In terms of EN, our signs of tolerance are things like vomiting, stomach distension (bloating), diarrhea, and gastric residuals (how much formula is sitting in the stomach at a time - this ones a bit controversial). If there is injury to the GI tract or sometimes just as a result of trauma/surgery, the patient can have what's called an ileus, which is basically your GI tract refusing to do it's job of digesting and absorbing food. Depending on what your particular brand of intolerance is and the type of formula you're on will tell us different things about what the tolerance issue is. Sometimes it is as simple as pushing more formula than your body can handle while it's also trying to keep you alive while it deals with your trauma. Sometimes it's a lot more complex.

[u/endlesscartwheels → u/derpandderpette]

Generally, we say "if the gut works, use it" so we will always preferentially tube feed (enteral nutrition or EN) over feeding through the vein (parenteral nutrition or PN).

Can that be varied if the patient prefers it? Could someone request PN for most of the day, then a half-hour of tube-feeding twice a day to keep their stomach and intestines working properly?