Rinsing with tap water and 0,9% NaCl solution

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In many western countries, most chronic and acute wounds can be rinsed using tap water. A general rule of thumb is that when the water coming from the tap is of drinking water quality, it can be used in wounds. It is wise to let the water run for about a minute because there usually is a concentration of bacteria around the tap opening. Again, this applies to areas with very good public water quality.

 

In many African countries, the water quality varies significantly from region to region. We can't state which areas of Africa it may be safe to use regular tap water to rinse wounds. Therefore, we generally advise boiling water for at least 5 minutes and cooling it down to body temperature before using it in wounds. If you sterilize glass bottles in an oven, you can use these to keep a stock of pre-boiled water. As a rule of thumb, such homemade clean water has a shelf life of no more than a week. 

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If the water source is a well, the chances are that the water is not ideal for wound irrigation. Of course, there are exceptions to this. Some deep wells provide us with the purest drinking water, while other wells may harbor many pathogenic bacteria. It is simply not possible to generalize this. However, to be on the safe side, it makes sense to say that water from wells should always be boiled before using it in wounds.  

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There are some exceptions to using regular tap water in wound care. The main exceptions are diabetic foot ulcers and clean wounds after surgery. Here it is advised to use sterile 0,9%  NaCl solution when irrigating a wound because any potential water contamination can have more severe consequences.  

 

In theory, isotonic water is even better to rinse wounds with than regular water. To make isotonic water, you add salt to the water to make a 0,9% NaCl solution ( about 9 grams salt to 1 Litre of water). The argument for using isotonic water is that it is more physiological - in other words, more similar to our body fluids, which also contain about 0,9% NaCl. Some researchers have even postulated that Ringer's solution ( which contains more electrolytes than regular 0,9%NaCl) may be even better as a rinse solution because it is even more physiological in its constituents. We believe, however, that these differences have little or nothing to say when we rinse a wound. 

 

At our clinic, we have drinking water quality coming from the taps. Nonetheless, we routinely use NaCl 0,9% to rinse wounds. This does not really make sense because we tell many patients that they can shower their wounds at home using regular tap water. It is simply out of habit that we use 0,9% NaCl at the clinic. It is cheap and readily available. We don't have to worry about shelf life as much, and it comes in handy sizes, which we can keep in the heater at 37 Celsius. 

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How much water should you use when rinsing a wound? This depends on several factors: whether the wound is clean or dirty, if there seems to be a high bacterial burden, or smelly. Another rule of thumb ( there have been many rules of thumbs in this chapter so far) is that we usually irrigate a wound with about 30-100ml water per 5 cm² wound area. 

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Rinsing with antibacterial solutions

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Let us get one thing straight from the start. Some caregivers have this over-optimistic view that many irrigation solutions will reduce bacterial numbers permanently by just one application. That is not the case. If you have a wound where you suspect a high bacterial burden, you have to use an antibacterial irrigation solution regularly, for example, daily. In addition, you should use an antibacterial dressing between irrigations. Antibacterial irrigation solutions will usually reduce the number of microorganisms quite effectively as long as the solution is in the wound. Still, once the dressing is in place, bacterial numbers start to rise again. 

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Most producers of antibacterial wound cleansers make a point that their product is also effective against MRSA. This makes the product sound exceptionally effective. MRSA is just as susceptible to antimicrobial wound cleansers as regular staphylococcal strains. MRSA is not a superbug that is resistant to disinfectants; they are resistant to the antibiotic methicillin. But of course, it is good to know that we also can inhibit MRSA with wound cleansers. 

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If you are using an antibacterial dressing, it may be sufficient to simply rinse the wound with 0,9% NaCl between dressing changes. We do not have the evidence to show that antibacterial irrigation solutions are more beneficial in all cases. We are trying to get at that many of us routinely use antibacterial rinse solutions without questioning whether this is actually necessary.  

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However, there are, of course, situations where we feel that it is appropriate to use antibacterial irrigation solutions. Typically these are wounds with a lot of necrosis and a heavy bacterial burden. In such situations, we like to think that by using an antibacterial rinse solution, we are aiding our antibacterial dressing to get rid of bacteria faster. In general, you will achieve little by just rinsing over the wounds with the solution. If you want it to work effectively, you should probably let the solution dwell in the wound for about 15- 20 minutes. There is no consensus on this, but it seems sensible to leave the solution in the wound for this amount of time. We expect cleansing agents to be even more effective when adding some mechanical force to the cleansing procedure. Applying the product to a soft brush or debridement cloth and rubbing gently over the wound with this makes sense. 

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There are many products available as antibacterial rinse solutions, and it may be confusing which one to use. Let us start with the ones we should not use anymore. Chlorhexidine 0,05% was previously used as a rinse solution in open wounds. Reports of cytotoxicity to healthy cells resulted in a consensus that it should not be used in open wounds anymore. It may have a negative impact on healthy granulation tissue, and there have also been reports of possible resistance developing in some bacterial strains. 

 

Hydrogen peroxide has also been criticized for having possible cytotoxic effects on healthy cells and is therefore no longer recommended as a wound rinse solution. In Africa, hydrogen peroxide is still widely used, and this practice will not go away soon. Consequently, we have looked at the research concerning hydrogen peroxide's possible cytotoxic side effects. These studies were done on cell cultures, and there is no solid evidence that hydrogen peroxide does any harm to an open wound. We used hydrogen peroxide extensively until about ten years ago, when it became unpopular in the western world. We are aware that several reports state that the antibacterial effect of hydrogen peroxide is short-lived, but in our experience, it helped to clean up wounds. We often saw that it promoted healthy granulation tissue and never documented any visible side effects.

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In conclusion about, hydrogen peroxide: if you have other alternative antimicrobial rinse solutions available, use these instead. If you only have hydrogen peroxide available, use that with a good conscience. It is not poison. The FDA approves it as a mouthwash of up to 3% concentration. We think that we do not need to become hysterical when someone uses hydrogen peroxide in wound care today. But we may point out that other, more "modern" options are available today. 

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As a general rule of thumb, we do not advise using soapy solutions to cleanse a wound unless the product has been specifically labeled for use in wound care. Soaps contain many different ingredients, and it is often impossible to say which of these ingredients are beneficial to a wound and which not. Some soaps also have an unfavorable high pH. There are, however, soaps and body washes that are suitable for wound care as well. Many types of soaps used for intimate hygiene are very gentle and often have a low pH. When should one consider using this type of product in a wound? In general, we do not need soap-based products to clean wounds. However, if we are concerned about biofilm, a soap-based product may help. Biofilms are disrupted by surfactants- that is, substances that reduce the surface tension. We use the same principle when we remove fat for a frying pan- we use a surfactant ( dishwasher soap) to facilitate the removal of the fat. Obviously, we cannot use dishwasher soap in wound care. But the point is- if we want to deal with biofilm, scrub with a gentle brush of cloth and a few drops of intimate body wash will probably clean the wound better than many other products.

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Biofilm removers or biofilm disrupting agents?

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How often is biofilm a problem in wounds? Some studies state that 70%% of chronic wounds have biofilm in the wound bed. This may be true, but it does not mean that 70% of chronic wounds have a biofilm problem. There are certainly some wounds where biofilm is preventing the wound from healing, but these are not as common as producers of antibacterial wound care products want us to believe. For those of us who have been in the game long enough, we know that we were able to treat wounds very adequately before we even knew what biofilm was. Don't get us wrong - we absolutely think that biofilm is an important issue. However, the focus on biofilm in the last years has been quite intense, resulting in that the only thing some wound care providers think about is biofilm. In our opinion, it has stolen too much focus from many other important aspects of wound care like off-loading, compression treatment, and re-vascularization. On occasion, however, we have a wound where we seem to be doing everything else correctly, but the wound will not heal. It may be wise to address a potential biofilm issue in these situations.  

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Which irrigation solutions affect bacterial biofilm? That is a very good question and not an easy one to answer. Biofilm has received much attention in the last 15 years. We agree that it is a fundamental concept, and some chronic wounds will not heal unless we address a possible biofilm problem. However, it is far from the main reason why many chronic ulcers will not heal. Some caregivers have focused so much on the issue of biofilm that they have entirely forgotten about other crucial aspects of wound care like re-vascularization, off-loading, and compression treatment, for example. But back to our question - do we really know which irrigation solution is best to remove biofilm? Many manufacturers of rinse solutions claim that their product can remove biofilm. Many products do not have good enough documentation for this claim. Even if a product can decrease the amount of biofilm in the laboratory, this tells us little or nothing about how it works in an actual wound. You also need to understand that biofilm is a complex structure that adheres firmly to the wound bed. It is not easily removed. If you wanted to remove it in one go, you would need to use something as strong as an industrial cleansing agent. This would be completely inappropriate to use in a wound as it would simultaneously cause irreversible harm to all healthy tissue. 

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The truth is that there is not a single rinse solution that simply removes biofilm in wounds. Today we no longer talk of biofilm removing agents but rather biofilm disrupting agents. This is a much more realistic term. It implies that some solutions can disrupt the outer cover of the biofilm, and upon repeated applications, the biofilm structure may crumble more and more. Many types of chemicals can disrupt the biofilm. Some of these products contain a surfactant, a chemical combination that works in many ways like soap. Others may attack the biofilm layer with acidity. The key is that the solution needs to be strong enough to actually harm the biofilm while being gentle enough on the healthy cells of the wound. 

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The biofilm disrupting agent with the most extended documentation is Prontosan by Braun. Prontosan contains two active substances - Betain is the surfactant, and polyhexanide is an antimicrobial substance. There are numerous studies done on this product. The majority of these studies are in-vitro research, but it is reasonable to conclude that the product is safe and that it has biofilm-disrupting properties. However, you have to turn down your expectations. If you simply rinse over the wound with this product, it will look very much the same afterward. The product does not just magically clean up the wound. To achieve some results, you need to apply the product at each dressing change. For best results, we recommend using a gel containing the same product underneath the dressing so that the Prontosan can work over more extended periods. For even better results, we recommend applying the product to the wound and scrubbing the wound gently with a soft brush or debridement cloth during dressing changes.

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We have to give Braun credit for putting in much effort to provide Prontosans efficacy and safety documentation. Many people are not aware of how many financial resources it takes to get such products approved in human medicine. At the same time, Braun has invested many resources to train health care workers on the topic of biofilms. Obviously, they aim to sell their product, but at the same time, we feel that they also had a genuine interest in educating wound care providers. However, their campaign was so effective that many healthcare workers believed that there was only one product on the market to battle biofilm. Prontosan was seen as an almost magical potion that could remove biofilm. It contains a soap-like substance and an antibacterial solution which we also find in rinse solutions for contact lenses. There is no more mystique to it than that. Prontosan is far from being the only solution that can disrupt the biofilm. But it may be one of the gentlest and best-tolerated solutions- and as we have stated several times now, it comes with several studies to back it up. 

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What is the documentation for other products with regards to disrupting biofilm? In the last years, some Prontosan imitations have appeared on the market. Prophase Wound Cleanser, for example, uses the same principles by combining PHMB and a surfactant  (Cocamidopropyl betaine). This product likely has similar properties to Prontosan.

 

While most producers claim that their product removes biofilm, many companies do not have solid enough evidence for this. You need to be vigilant and ask the right questions. How was the research done? If the product was tested on biofilm samples in the laboratory, this tells us very little about the product's abilities in a chronic wound. 

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Vinegar appears to be a very good biofilm disrupting agent. In fact, it may be as good a biofilm disrupting agent as any other. So if you do not have the resources to buy specialized biofilm disrupting agents, you can use 3% vinegar rinse solutions. Let the vinegar solution dwell in the wound for about 15-20 minutes at each dressing change. 

 

Remember that one of the essential aspects of biofilm removal is sharp debridement. If you believe that you have an issue with biofilm in the wound, debride it gently with a ring curette or a scalpel, then apply a biofilm disrupting agent and let it dwell in the wound for at least 15 minutes. Repeat this at each dressing change until the wound clears up.  

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Let us look at what options we have when it comes to solutions we can use for rinsing wounds. We have listed solutions you can make yourself and those that are commercially available, and we briefly discuss some aspects of each solution here.