The following is excerpted from Dr. Jefferey Hill’s “Workshop Wound Care.” The book – the newest offering in our pocket book series – delves right to the heart of what you need to know when faced with common workshop injuries, from lacerations, to puncture wounds to material in the eye. Dr. Hill is an emergency room physician and an active woodworker. So he knows exactly the information a woodworker needs to know when it comes to injuries. And he presents information in a way that a non-medical professional can easily understand it.
The initial steps of wound care are critically important to creating an environment that promotes healing with a quick return to normal function and (if it’s a concern of yours) good cosmetic outcomes. As we covered in Chapter 4, Wound Healing Primer, there are a number of factors that can affect the healing process.
Wounds that heal well have minimal tissue damage, don’t get infected and have tissue layers that line up well. The amount of tissue damage is, generally speaking, a function of the way the injury occurred (crush injuries mean more tissue destruction as opposed to lacerations, which have minimal destruction apart from the severed tissue layers). Sometimes, however, actions taken early in the wound care process can worsen some of the existing tissue damage, or, in the very least, can fight against creating the optimal healing environment.
Stopping ongoing bleeding is clearly the first step in addressing a fresh wound. But assuming the wound is small-ish and the bleeding is not severe enough to prompt you to seek care at your local urgent care or emergency department, your next steps should be focused on cleaning the wound to prevent infection.
In preventing wound infections, the single-most important step is thorough irrigation of the wound. Even a dump truck full of antibiotics won’t prevent an infection in a contaminated wound that wasn’t cleaned. Why? Exponential growth is the reason. A characteristic of exponential growth is that things seem fine until they aren’t and when things get bad, they get bad quickly (see the global COVID-19 pandemic).
Staphylococcus aureus, one of the more common bacteria on your skin and a frequent cause of wound infections, has a doubling time of about 90 minutes. So two bacteria become four in 90 minutes, four becomes eight in three hours, eight becomes 16 in four-and-a-half hours, 16 becomes 256 in six hours. Not too bad, honestly. By 24 hours you’re up to more than 130,000 bacteria in the wound. But, let’s say instead of starting with a wound with only two bacteria, you start in a wound that has 100 bacteria. This time, by 6 hours you’re at 1,600 bacteria. By 12 hours, 25,600. And by 24 hours, more than 6.5 million bacteria are in the wound.
Antibiotics are great and all, but by the time you get them prescribed, filled at the pharmacy, into your stomach, to the bloodstream and out to the wound, they would be greeted by a mass of hundreds of thousands to millions of bacteria.
This isn’t to say that antibiotics don’t have a role in preventing wound infections. They do, and are prescribed in certain circumstances based on the types of tissues injured, risk of infection and ability of the patient to fight off infections. But, the single-most important thing you can do to prevent a wound infection is to clean the wound thoroughly and decrease the bacteria cell counts in the wound. Get that number small enough, and the roving white blood cells that come to a healing wound will usually be able to take care of things.
‘Dilution is the Solution to Pollution’
Bacteria find their way into wounds in a number of ways. First, understand that bacteria are literally everywhere. They are on you, your skin, your chisel, your table saw blade, that nice piece of white oak that gave you a splinter while you were trying to rive out some leg stock. Everywhere. Bacteria can be forced from your skin into a wound by the chisel or whatever else caused your injury. They can catch a ride on a tiny sliver of wood or metal. Or they could be pressed into the wound as you try to hold a grimy rag to it attempting to stanch bleeding.
The goal of irrigation is to rid the wound of as many bacteria and as much bacteria-laden detritus as possible. As the old surgical maxim “dilution is the solution to pollution” suggests, the prime way that this is accomplished is through flowing a large volume of water over and through the wound. The surest way to clean the wound of bacteria and any foreign bodies is through a combination of volume and pressure.
The setup for this irrigation is shown in the photo [Above]. The splash guard is basically a fancy 19-gauge blunt plastic needle with a shield to keep water from spraying everywhere while you irrigate the wound. The combination of the syringe and this splash guard results in a flow of saline/water with pressures around 25 to 35 psi.
What About Tap Water?
How much volume is enough volume? The general rule of thumb is that wounds should be irrigated with 500ml to 1L of fluid. But in practice, the real goal is to make sure the wounds are completely free of foreign bodies. Wounds that are clean in appearance to begin with might get away with smaller volumes of irrigation depending on location, depth of the wound and mechanism of injury.What About Tap Water?The type of irrigation just described is important for wounds that are relatively deep or fairly contaminated. Most of the wounds you’ll sustain in the workshop will be relatively small nicks, cuts and skin tears. For these minor wounds, thorough irrigation with tap water will do. In fact, there are a number of studies that show no difference in infection rates for wounds cleansed with tap water vs. saline, even for larger wounds. This of course assumes that the source of the tap water is clean – not really a concern for most municipal water sources, but could be a concern in developing nations or in underdeveloped and under-resourced pockets of the United States.
The process for irrigating a wound with tap water is quite simple (if a bit painful). Turn the tap to lukewarm/body temperature water (those newly exposed nerve fibers will be exceedingly sensitive to any stimuli). Let the water run over the wound for several minutes. Re-examine the wound to see if there is any debris remaining. If there is, you can try to irrigate again, or try to irrigate with the pressure irrigation setup described above, if you have a syringe with a splash guard. However, if the wound is that dirty you might need a more thorough irrigation in a healthcare setting.
Why not Hydrogen Peroxide, Iodine etc.
Apart from water or saline, the only other thing that should be used to clean a wound is a mild soap and maybe a dilute iodine solution.
My experience while growing up in the United States Midwest was that every scrape, nick or cut should be cleaned out with hydrogen peroxide every day until the wound healed. And why not? It bubbles like mad, stings a bit and the wound looks a good deal cleaner afterward.
There are a number of problems with using hydrogen peroxide to clean wounds. For starters, it does a much better job of killing red blood cells than it does of killing bacteria. This can be helpful for wounds that have a lot of dried, caked-on blood as can often happen with wounds in hairy areas. It is far less helpful for your standard wound. For wounds that are a couple of days into healing, hydrogen peroxide has been shown to separate newly minted skin cells from the healing tissue at the base of wounds. And, in experimental conditions, hydrogen peroxide has been shown to delay wound healing. If you do choose to use hydrogen peroxide to clean dried blood off, be ready for some heat. The chemical degradation of hydrogen peroxide to water and oxygen is exothermic (it gives off heat). It’s not enough to cause any thermal burns to the area, but it is quite noticeable.
Iodine is frequently used to clean wounds and does have some advantages over saline irrigation alone in some situations. Iodine is sold in two formulations: a solution and a scrub. The scrub was designed for use on intact skin and for cleaning the skin surface prior to surgery. The detergent mixed into the scrub is toxic to tissues and shouldn’t be used in open wounds. Iodine solution is typically sold at a 10 percent concentration. When it is diluted to less than 1 percent, it is safe for use in open wounds and has excellent antibacterial, anti-viral and anti-fungal activity. In the emergency department, iodine-diluted solutions are typically used for irrigating wounds at high risk of infection (based on mechanism, contamination, location).
Chlorhexadine is a surgical scrub soap that is also widely available. It was also designed for use primarily with intact skin. If you have had an elective surgery you may have been instructed to shower with it for several days/weeks prior to the surgery. The reason being that it builds up on the skin surface and has potent anti-bacterial properties (great for decreasing the risk of surgical site infection). It also has a detergent that can be toxic to the tissues in open wounds so its use in wound irrigation is discouraged.
Soaps work by liquefying fats and oils, making them soluble in water and able to be carried away by running water. Because bacterial cell walls are made of fat, soap is able to dissolve some of these cell membranes, killing the bacteria. Commercially available soaps are all generally quite mild in their fat-busting properties (they are fairly mild detergents) meaning that they should not be particularly toxic to open wounds.
Putting it all together, how should you clean your wound?
First inspect the wound. Large, gaping wounds or wounds that have a lot of debris in them will likely need to be cleaned and repaired in a healthcare setting. Some initial irrigation of these wounds with running tap water may help you triage the wound and may help lightly clean it in preparation for a more thorough cleaning by a medical professional. After you irrigate under running tap water, cover the wound with sterile gauze that has been dampened with sterile saline and head to your local medical facility.
Smaller wounds, scrapes and lightly contaminated wounds that you feel can be dealt with at home should be first lightly cleaned with soap and water. Then allow lukewarm tap water to run over the wound for several minutes until it appears to be clean to your eye and no debris remains. If you still see some debris, you can try to use the aerosolized saline wound washes that are available in your local drugstore. It’s not clear how the pressures generated by these products compare to the pressure irrigation setup used in your local emergency department. As a general rule of thumb, if the wound still appears dirty, then you’ll need more aggressive cleaning by a healthcare professional and should seek care.
Do note that oftentimes the process of cleaning and irrigating the wound may cause it to start bleeding (you may have washed away the blood clots that stopped any previous bleeding). That’s OK. After you have finished cleaning the wound, you should be able to stop the bleeding again with a combination of direct pressure and maybe a pressure dressing.
After the wound is cleaned thoroughly and the bleeding has been stopped, you’re on to dressing the wound to keep it clean and promote healing.