What are wound cleansers?
Wound cleansers are rinsing solutions used to remove foreign materials on a wound surface and its surrounding skin.
Wound cleansers are a cost-effective means to promote wound healing and reduce the infection rate. However, routine cleansing may also remove products and tissues that are essential for wound healing, such as regenerating epithelium, growth factors, and chemokines.
What is the therapeutic indication for a wound cleanser?
A cleanser should be used as the first step in every acute or chronic wound bed preparation. The cleansers are intended to remove foreign bodies and reduce the risk of infection.
What should be considered when choosing a wound cleanser?
In clinical practice, the decision on which cleansing agent to use has been largely based on local guidelines and personal preference.
An ideal wound-cleansing solution would:
- Be non-cytotoxic
- Not induce an immune response (be biocompatible)
- Reduce the numbers of pathogenic bacteria
- Not induce bacterial resistance (see methicillin-resistant Staphylococcus aureus [MRSA])
- Be non-sensitising
- Be easily accessible
- Be cost-effective
- Be stable with a long shelf life.
Types of wound cleansers
Wound cleansers include water, saline, and antimicrobial agents. Dyes and organic mercury compounds are considered obsolete.
- Drinking water has an excellent safety profile.
- It is efficient, cost-effective, and easily accessible.
- Drinking water is an acceptable alternative when sterile water and normal saline are not available.
- The rate of wound infection when tap water is used is similar to that with normal saline.
- Tap water is a possible infection risk and should be avoided in a deep wound, especially when there is an exposure of bone or tendon.
- The solution is not isotonic.
- Sterile water is an option when normal saline is contraindicated or not available.
- Sterile water does not induce fever and has no antimicrobial properties.
- The unused contents of opened containers should be discarded.
- It is a non-buffered hypotonic solution with an osmolarity (concentration of solute particles per litre in a solution) of 0 osmol/L; this may result in cellular oedema and rupture.
- Prolonged soaking in water can result in increased wound exudate, requiring frequent dressing changes.
- Sterile water does not promote wound healing in the presence of a pathogenic biofilm.
- Irrigation with sterile water can be painful; analgesia may be required.
Normal saline (0.9% NaCl)
- Normal saline is an isotonic solution that does not interfere with normal wound repair.
- It has low toxicity compared to other wound-cleansing solutions.
- It does not cause an allergic reaction or change the normal flora of the skin.
- Normal saline has a similar wound infection rate to drinkable tap water.
- Normal saline does not cleanse dirty or necrotic wounds effectively.
- It has no antimicrobial properties.
- The unused contents of opened containers should be discarded.
Antimicrobial wound cleansers
Older guidelines have discouraged the use of conventional antiseptic solutions as these impair wound healing, reduce wound strength, and increase the rate of infection.
In contrast, newer broad-spectrum antimicrobial cleansing products can reduce microorganism colonisation and infection rates, and some of them promote wound healing. They can be used in acute and chronic wounds, deep wounds, or superficial wounds.
- Acetic acid (vinegar) is inexpensive and readily available.
- It is effective against Staphylococcus aureus, MRSA, Pseudomonas aeruginosa, and other Gram-negative bacteria.
- It promotes wound healing.
- Acetic acid may sting on application if the solution is > 2% acetic acid in water (neat vinegar is typically 5-8% acetic acid).
- Chlorhexidine is a broad-spectrum antibacterial solution.
- It prevents the penetration and systematic spreading of bacteria, including MRSA (excluding any deep muscle invasion).
- Chlorhexidine can cause skin irritation.
- When used as a mouthwash, it can cause teeth discolouration.
- Rarely, it may be a sensitiser, causing allergic contact dermatitis.
- Application around the eyes may cause conjunctivitis and corneal ulcers.
- It does not affect mycobacteria, bacterial spores and certain viruses, including polioviruses and adenoviruses.
- Chlorhexidine is pH-dependent.
- Body fluids and tap water may inactivate its antibacterial properties.
- Povidone iodine (PVP-I), a stable chemical complex of polyvinylpyrrolidone and iodine, is useful for acute open wounds such as human or animal bites, stabs/punctures, and gunshot wounds.
- It is a broad-spectrum antimicrobial solution that provides limited coverage for many types of pathogens (eg, S. aureus, dermatophytes, yeasts, and viruses).
- Some studies have demonstrated a reduced infection rate in surgical wounds with the use of PVP-I.
- It may be useful in treating excessive granulation tissue.
- Povidone iodine is a cytotoxic agent that can delay wound healing.
- It can cause irritation, dryness, and discolouration.
- It is a sensitiser and has adverse effects on the thyroid gland.
- Povidone is not suitable for chronic wounds. Do not use it for more than 7 days.
Hydrogen peroxide (H202) is now rarely used as a wound cleanser.
When used at full strength, hydrogen peroxide may act as a chemical debriding agent that effectively removes debris and necrotic tissues from the wound surface.
- Irrigation with normal saline is recommended after full-strength hydrogen peroxide is used.
- Hydrogen peroxide is cytotoxic and may interfere with cellular homeostasis and delay wound healing and closure.
- It should be avoided in wounds around the sinus tracts.
Sodium hypochlorite 0.4–0.5% (Dakin solution)
- Diluted bleach has bactericidal properties including on biofilm.
- Sodium hypochlorite 0.4–0.5% (Dakin solution) is indicated in pressure ulcers with necrotic wounds to help reduce and control infection.
- It can be used to wash out deep wounds and cavities.
- It has been used over cancerous growths to control infection.
- It reduces odour.
Superoxidised solution is also known as superoxidised water, anolyte solution, electrolysed water, and oxidative potential water. It is an electrochemically processed solution made from water and sodium chloride (salt), resulting in a pH neutral combination of hypochlorous acid and sodium hypochlorite.
- Superoxidised solution can be used in all types of wounds.
- It reduces bacterial colonisation, biofilm, and inflammation.
- It enhances wound healing.
- It is non-toxic, non-sensitising, and non-irritating.
Octenidine solution is used for superficial skin wounds and should be avoided in wounds near the sinus tracts.
- Octenidine is effective against P. aeruginosa and S. aureus biofilm.
- It can be used for the decolonisation of multidrug-resistant organisms.
- It promotes wound healing and is non-sensitising.
- Polyhexethylene biguanide (PHMB), also known as polyhexanide, is the antiseptic of choice for colonised and infected chronic wounds and burns.
- It is a broad-spectrum antimicrobial that is effective against a variety of pathogens, including MRSA, P. aeruginosa and other bacteria.
- Studies have shown that it accelerates wound healing and decreases the bacterial count.
- It does not cause antimicrobial resistance.
- PHMB has good clinical safety and is well tolerated with minimal toxicity.
- Contact allergy and anaphylaxis from PHMB have rarely been reported.
- PHMB does not interfere with cell homeostasis as it is not absorbed by cells.
PHMB combined with undecylenamidopropyl betaine
Undecylenamidopropyl betaine is a surfactant (detergent) that effectively removes biofilm and debris and prevents recontamination.
- The combination of PHMB and betaine enhances the antimicrobial effect and reduces cytotoxicity.
- This combination has been clinically proven to be more effective in the removal of biofilm, debris, slough, and bioburden in wounds compared to normal saline.
- It is suitable for long-term use on thermal burns, as it is not absorbed by the cells.
- It provides an optimal environment for wound repair.
- Unlike other antiseptics, it does not inhibit the formation of granulation tissue.
- It has been shown to reduce the duration of healing, infection, and inflammation.
- It promotes healing in venous leg ulcers and pressure ulcers.
- It provides odour control.
- PHMB and betaine may irritate in long-term use.