Wound cleansers

Do we need to rinse a wound at all? It has become a habit to remove the old dressing and routinely irrigate it with water or another rinsing solution. While this may be a useful procedure if we have wounds with an increased bacterial burden or necrosis, there is no evidence that this routine is useful for all wounds. If the wound looks clean, does not smell, and seems to be progressing well, there is no need to irrigate the wound with anything. 

It is generally recommended that we use irrigation solutions with body temperature when rinsing a wound. The theory behind this is that cold rinse solutions can significantly lower the temperature in a wound, slowing down the healing process for many hours. We do not need to get hysterical if we wash a wound with room-temperated wound cleansers. Most wounds worldwide are still irrigated using room temperated solutions. However, if you have a heated storage box to store solutions at 37 C, this is probably better.   

The following chapter is quite lengthy. The topic of wound cleansers is complicated. There are many products to choose from. Which products should be used when? Are there some products that we should avoid? We have spent some time on this chapter to shed light on the most common questions. We advise you to take your time to read through this. Wound cleansers are products we use every day in wound care, and it makes sense that we should have a good basic understanding of this product group.   At the end of the chapter, we listed the key players in the family of wound cleansers. 

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Figure 1 There is much confusion about which wound cleanser to use in which situation. In this diagram, we have arranged the products according to the bacterial burden of the wound. The diagram reflects the way we use these products at our clinic. The diagram thus represents " expert opinion" rather than evidence-based practice. 

Rinsing with tap water and 0,9% NaCl solution

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. 

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.  

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. 

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. 

Rinsing with antibacterial solutions

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. 

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. 

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.  

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. 

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.

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. 

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.

Biofilm removers or biofilm disrupting agents?

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.  

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. 

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. 

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.

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. 

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. 

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.  

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. 

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Regular tap water

In western countries, regular tap water can be used for rinsing wounds as long as it has drinking water quality. This may also apply to some parts of Africa where the public water supply is of very good quality. However, for most regions in Africa, tap water should be boiled for at least 5 minutes before using it for wound care. 
 

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Home-made isotonic saltwater

Add 9 grams of salt to 1 Liter of boiled water to make your own isotonic 0,9% NaCl solution. This can be stored for up to a week if you have used sterilized bottles as containers. 
 

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Home -made hypertonic salt water solution

Studies show that salt concentrations equivalent to seawater ( about 3,5%) have an antibacterial effect while not causing harm to healthy cells.  To make this, you add 35 grams salt to 1 Litre of boiled water.  As with most rinse solutions, the antibacterial effect is not long-lasting.
 

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Sterile 0,9% NaCl

Regular tap water should not be used as a rinse solution in complicated ulcers with exposed bone, tendon, or hardware ( orthopedic implants, for example). We are also hesitant to use regular water in diabetic wounds as these can get infected easier. Instead, we have to use sterile 0,9% NaCl in these cases. Alternatively, we can use an antimicrobial washing solution.
 

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Wound wash containing zinc

Zinc has antimicrobial activity. It has been added to mouth rinses and toothpaste to control dental plaque, inhibit calculus formation and reduce halitosis. It is considered a bacteriostatic agent rather than a bactericidal. Interestingly, the bacterial inhibiting effect appears to persist for several hours after application. Several producers have wound washes that contain zinc as the main active ingredient. Examples are 3M Wound Cleanser and CVS Zinc Wound Wash. We have not tried these ourselves but like using zinc because it also has anti-inflammatory properties and several physiological processes going on in a wound like zinc. In effect, when using zinc, we not only inhibit bacteria but also supply the wound with something helpful in wound healing.  

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Home-made 1% -2%vinegar rinse solution

The literature suggests that 1%- 2% vinegar is an effective antimicrobial rinsing agent. It has the advantage that it also lowers the pH of the wound ( temporarily), which is beneficial to the wound healing processes. Like most antimicrobial solutions, the antibacterial effect is short-lasting, and an antibacterial dressing should be used if you suspect a high bacterial load in the wound. You can use regular clear household vinegar to make this. This type of vinegar is often sold at around 5- 7%, and you have to dilute it accordingly with boiled water that has cooled down. 
 

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Acetate buffer ( sodium acetate buffer)

Some clinics use standardized vinegar solutions which are prepared by pharmaceutical standards. These solutions contain vinegar and vinegar salts ( often sodium-acetate) to give the solution buffering properties. By buffering a vinegar solution, it not only has a predictable pH value ( often pH four is used for wound care purposes), but it is thought that the pH can remain more stable when the solution comes into contact with wound exudate. In theory, regular vinegar may be neutralized within shorter periods when it comes into contact with wound exudate.   Whether the theoretical advantage of buffered acetic acid really makes a difference in a wound is unknown. Most studies on vinegar in wounds have been done with regular vinegar. However, if acetic acetate buffer is available at your clinic, using this instead of ordinary household vinegar makes sense. 
 

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Vinegar and Surfactant Wound Wash

This type of wound wash combines the biofilm disrupting properties of a surfactant with vinegar's antimicrobial and pH regulating properties. There are surprisingly few products like this available. One such product is Optima pH Skin Wash, manufactured in Norway and is mainly distributed in Scandinavia. Ideally, it should be applied on a soft brush or a debridement cloth with which the wound is cleansed. We have not found any documentation about the properties of this type of product.  

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Solutions with PHMB

Polyhexethylene biguanide (PHMB), also known as polyhexanide, is used in many antibacterial wound cleansing solutions. PHMB is a broad-spectrum antimicrobial effective against various pathogens, including Staphylococcus aureus, Pseudomonas aeroginosa, and other bacteria. Some solutions contain only PHMB as the active ingredients, while others also include a surfactant- see the next group below. There are several producers of PHMB based was solutions. The image on the left shows Biakos Antimicrobial Skin and Wound Cleanser by Sanara MedTech.

 

In our experience, this type of wound cleanser is not strong enough if you have a wound with, for example, heavy colonization with P. aeruginosa. In this scenario, you will need a more potent solution like povidone-iodine or acetic acid. 

In recent years there has been a discussion about the safety of PHMB, and high concentrations of PHMB may be cancerogenic. However, the amounts of PHMB in these wash solutions are relatively low, and to date, these concentrations are generally accepted as safe. 


 

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Solutions with PHMB and Betaine

Prontosan was one of the first products on the market explicitly designed to tackle bacterial biofilms. It is one of few products with relatively solid documentation. 

Prontosan contains PHMB ( the antimicrobial agent) combined with undecylenamidopropyl betaine ( the surfactant).   Neither are very aggressive substances and are very well tolerated. As we mentioned earlier, this sort of product works fairly slowly and needs repeated application. Preferably you should use the solution to scrub the wound with a soft brush or a debridement cloth. Alternatively, you can moisten gauze with the solution and let it lie on the wound for 15-120 minutes. The product is also available as a gel which can be used a s a wound filler to provide longer lasting action of the product. In recent years other producers of PHMB + surfactant solutions have appeared on the market - for example Prophase Wound Cleanser. 

In our experience this type of  wound cleanser is not effective enough if you have a wound with for example heavy colonization with P. aeruginosa. In this type of scenario you will need a stronger solution like povidone- iodine or acetic acid. 

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Other solutions with a surfactant + antimicrobial agent

The idea of combining a surfactant with an antimicrobial agent makes sense. The surfactant disrupts the surface of a biofilm, and the antimicrobial agent inhibits the bacteria in the exudate and those released from the disrupted biofilm. 

 

Octenilin came onto the market a few years ago and challenged the leading position of Prontosan as a biofilm disrupting agent. Like Pronotosan, Octenilin contains a surfactant (Ethylhexyl glycerine)  and an antimicrobial agent (Octenidin HCL). From its documentation, it appears that it has similar properties to its competitor Prontosan. 

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Super oxidised solutions (Hypochlorous Acid)

A super oxidized solution comprises a low concentration of salt (sodium chloride), dissolved in water, into which an electric current is passed. This produces a mixture of charged particles (ions), mostly comprised of hydrogen, oxygen, and chlorine combinations. These ions rearrange to form new compunds like hypochlorous acid and sodium hypochlorite. These substances all have antimicrobial properties, attacking bacteria on various fronts. The antimicrobial effect happens within a few minutes, but again,  the effect is not long lasting. 

Although super oxidized solutions have  very good mirobiocidal properties they are very gentle to healthy tissue and extremely well tolerated. They are also commonly used for irrigation during negative pressure treatments. We do not know much about how effective they are on biofilm. They do not contain any active substances like surfactants. 

Superoxidised solution is also known as superoxidised water, anolyte solution, electrolysed water, and oxidative potential water. It is sold as a rinse solution and as a gel as a wound filler. It is cheap and easy to produce and accordingly there are many different brands to choose from. 

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Povidone-iodine solution

Today, there is sufficient documentation to show that Povidone-iodine is a safe and highly effective antimicrobial agent. Until a few years ago, there was quite some controversy about this product. Today the product has retaken its position as one of the most valuable antimicrobials solutions we have. In fact, it may be one of the best biofilm disrupting agents we have - especially concerning biofilm from Pseudomonas and staphylococcus aureus. It is usually sold as a 10% solution. If the wound has a heavy bacterial load, you can use it at this strength. Once the wound clears up, we recommend using a diluted concentration for a few more days, like every other antimicrobial solution on this list. If you simply irrigate the wound with PI solution, the antibacterial effect is not long-lasting. To achieve a longer-lasting effect, you can fill the wound with PI gel after the rinse. 

We do not recommend using the PI solution as your routine wound wash for every wound. If you are treating a wound which is doing well- why would you want to disturb the bacterial balance in the wound with something as strong as PI? Use it only when you really have to deal with severe bacterial contamination.  

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Wash solutions for intimate hygiene

Intimate wash solutions contain mild surfactants which can have biofilm-disrupting properties. They can be used as a mild soap and applied using a soft brush or a debridement cloth. As a rule of thumb: if it is gentle enough to be used on the vaginal epithelium, it will not cause harm to a wound. Avoid intimate washes that have many unnecessary additives like scents. Choose an intimate wash with low pH. Rinse out the wash solution with clean water afterward. 
 

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Sodium Hypochlorite 0,4-0,5%(Dakin`s solution)

Dakin`s solution is an old wound wash solution that has recently seen a revival of its popularity. It is actually diluted bleach. Sodium hypochlorite ( NaOCl) is often used in household bleaches, although in much stronger concentrations. Although Dakin`s solution has shown very good antimicrobial properties, we do not recommend it ourselves because it has an alkaline pH of around 10-11. If we follow the principle that wounds prefer a ph below 7 to heal, using an alkaline rinse solution feels wrong when other good alternatives are available. 
 

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Hydrogen peroxide (H2O2)

In many areas of Africa, hydrogen peroxide is still commonly used as a wound rinsing solution. In western countries, however, it is only rarely used today. It is considered cytotoxic, may interfere with cellular homeostasis, and actually delay wound healing. The antibacterial effect of hydrogen peroxide is also considered to be relatively short ( but isn't that the case with most wound cleansers?)

As mentioned in the chapter above, hydrogen peroxide isn't a poison. It was a very popular product only about 15 years ago, and it may not appear so obvious that it has a negative impact on wound healing. We used it extensively many years ago and found it to promote the healing of wounds rather than delay wound healing. However, if studies show that the product is not optimal for wound healing, we should avoid using it as other alternatives are available. 
 

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Chlorhexidine 0,05%

Chlorhexidine is a potent broad-spectrum antimicrobial agent. It is commonly used as a skin disinfectant before surgical procedures. At lower concentrations (0,05%), it has previously been used as a wound cleansing solution. This practice is seen as obsolete today. Chlorhexidine sometimes causes skin irritation, and it is thought to have cytotoxic properties which may delay wound healing. There is no rationale for using this product in open wounds when we have equally potent antimicrobials like povidone-iodine of acetic acid. 

Video 1  A film by BBraun explaining how Prontosan works in a wound

Video 2  A film by Schülke explaining how Octenilin works in a wound

Video 3  A film by Mölnlycke showing how Granudacyn is used in practice at the Podos Clinic in Poland