I suspect it will take a while for the wilderness medicine and other civilian first aid protocols to catch up to the military protocol described by Dean. Dean, thank you! You sure make me feel better about not carrying a syringe! I figured that I could put a sewing needle hole in a plastic bag if needed (in fact, the WFA class I took two of years ago suggested this and that the syringe's place is primarily in a group kit). But if low pressure irrigation is preferred, I don't even need to do that!
The one time (in my 70-year backpacking career plus raising 4 kids) that I encountered a really contaminated wound was in a car campground. My kids were playing baseball (one-old-cat) with the kids in the campsite next door. One of the neighbor boys slid into home base (a good-sized rock) on one knee. Of course my kids called me over, telling the neighbor parents that I had just finished a mountaineering first aid class and could take care of it. Ha! I took one look at the knee--a big flap of skin peeled back with a lot of dirt imbedded in the tissue underneath--and strongly advised the parents that the two hour drive to the nearest ER was a really good idea. I pointed out that I could get the wound clean, but that the pain would be excruciating! In any case, a tetanus shot would be needed and stitches were probably indicated. I even offered to take care of the other kids, but they decided they might as well take the others since they'd have to eat dinner out anyway. They came back six hours later with a much happier boy, all cleaned and patched up (under local anesthesia) and ready to play ball again (although far more cautiously, with a substitute base runner) the next day! If we'd been 15 miles' hike from the nearest trailhead, of course, I'd have had to do the cleanup job.
It's really great to have a physician with so much trauma experience in the BPL community!