Mick Willcox, BN, is an army staff nurse, Queen Alexandra Hospital, Portsmouth.
Wound cleansing should create an optimal healing environment by removing excess debris, exudates, foreign and necrotic material. Although the primary aim is not to remove bacteria, reducing the number of bacteria as a consequence can be beneficial and can help promote healing (Falanga, 2000). During healing, a continual process of change takes place at the wound bed (Falanga, 2000). It is most important to understand the stages of wound healing so that an accurate assessment of the wound can be made.
A study into wound bed preparation suggests that cleansing a wound to remove debris, excess exudate and contaminants is a means of helping to manage the exudate and reduce the bacterial burden of the wound (Falanga, 2000).
Swabbing a wound has been shown to be an ineffective method of cleansing it. This is because during the swabbing process, debris and bacteria are redistributed around the wound (Bale and Jones, 1997), and granulation tissue in the wound bed can be damaged, which prolongs the inflammatory stage of healing.
Physical methods of removing debris and contamination using forceps and gloved fingers have also been shown to be ineffective (Davies, 1999).
Irrigation involves applying a solution to the wound and allowing this to run off it with any debris and contaminants. The difficulty with irrigation is maintaining an optimum pressure (measured in pounds per square inch - psi), to clean the wound (Oliver, 1997): low pressure will not remove all the debris, while too high a pressure will damage epithelialising cells and even force fluid into the interstitial space.
According to Fletcher (1997), pressure is dictated by the size of syringe, quill or needle, and the pressure applied to the plunger.
Bergstrom et al (1994) suggest that a pressure of 8psi is effective for cleaning a wound and that this can be achieved using a 35ml syringe and a 19-gauge needle. However, this method is very unreliable owing to the variable forces that are applied to the plunger by the operator. The recommended pressure required to clean a wound varies in the literature.
Other methods of irrigation include using commercially produced pressurised containers and soft squeeze pods containing normal saline (Davies, 1999).
Royal College of Nursing guidelines for clinical practice (RCN, 1998) suggest that there is very little evidence to support any method of cleansing wounds, but recommends irrigation as best practice. However, no guidelines are given as to how this should be carried out.
There is little evidence to support the use of bathing and showering as a method of wound cleansing. Cross-infection can occur when patients share baths, therefore these should be thoroughly cleansed before and after use (Blunt, 2001).
Splash back is a potential hazard of wound irrigation, therefore eye protection should be worn. There are also problems associated with the collecting and catching of the solution used to irrigate the wound, and care must be taken to avoid contamination of other sites and materials (Williams, 1999).
Routine use of antiseptics and disinfectants is not recommended, as they damage newly formed tissue and require 20 minutes’ contact time to work effectively (Blunt, 2001).
However, there is evidence that the incidence of infection is lower when tap water is used to clean wounds as opposed to using normal saline (Fernandez et al, 2003).
There is no evidence that organisms from tap water colonise wounds (Wardrope and Edhouse, 1999). However, normal saline is isotonic (physiologically balanced so that it has a similar osmotic pressure to living cells), which means that it does not donate fluid to a wound or draw fluid from it.
Because water is not isotonic it is suggested that it could cause tissue damage, which may be detrimental for wound bed preparation (Lawrence, 1997).
In addition, guidance on the amount of solution needed is not uniform; suggestions range from just 15 millilitres up to one litre of fluid (Fernandez et al, 2003).
A warm environment promotes mitotic (cell division) activity in healing wounds, such activity reducing when the wound temperature drops. It is therefore important to keep a wound warm (Williams, 1999).
It can take 40 minutes for a wound to return to its optimum temperature after a dressing change and three hours for mitotic activity to return to its normal rate (Williams, 1999).
Warming water and normal saline before use can help to maintain an optimal wound temperature. This is also more comfortable for the patient (Gershoff et al, 2001).
It is imperative that practitioners carrying out wound care procedures understand the wound healing process. It is only by doing so that they will be able to make an informed decision on whether or not, and how, to clean it.
It is evident, therefore, that more research into wound cleansing is required (Blunt, 2001).