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Can tap water be used to irrigate wounds in A&E?

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VOL: 98, ISSUE: 14, PAGE NO: 56

Daniel O’Neill, BSc, RGN, PGDipRN, is a staff nurse, A&E Department, Frimley Park Hospital, Camberley, Surrey

The average A&E department treats approximately 16,500 patients with open traumatic wounds each year (Walsh, 1996). The aim of treating these wounds is to encourage healing and prevent infection. In current practice, normal saline (0.9% NaCl) is generally used to cleanse and irrigate wounds, although its use may be more ritualistic than evidence-based.

The average A&E department treats approximately 16,500 patients with open traumatic wounds each year (Walsh, 1996). The aim of treating these wounds is to encourage healing and prevent infection. In current practice, normal saline (0.9% NaCl) is generally used to cleanse and irrigate wounds, although its use may be more ritualistic than evidence-based. All open traumatic wounds are contaminated on presentation in A&E, and usually debridement and thorough irrigation are required to remove loose debris (Walsh, 1996). Irrigation removes loose devitalised tissue and has been shown to reduce the infection rate in contaminated wounds (Longmire, 1987). However, although the wounds are considered to be contaminated there is no evidence that open wounds need to be sterile (Walsh, 1996). A number of studies have investigated the bacterial cleanliness of tap water in A&E departments for its possible use in cleansing and irrigating open traumatic wounds (Riyat and Quinton, 1997). If suitable, it would be convenient and easy to use and could save money, improving both the efficiency and financial outcomes of A&E departments (Altemeier, 1994). This article analyses research into the effectiveness of tap water in comparison to normal saline for wound cleansing in A&E nursing practice.

Literature review
Seven research-based articles were found in a literature search on the use of tap water in wound irrigation and were subjected to critique by review and analysis. Most used quantitative studies involving UK, US and European research published in key journals between 1990 and 2000. The population samples in the articles were of mixed international race, in hospital settings. All the studies used tap water of drinking quality in the A&E department. A number examined patients presenting to the A&E department with acute traumatic soft tissue wounds; also included were two rat studies (Dire, 1990; Riyat and Quinton, 1997; Moscati, 1998). The researchers cultured for the same contaminating organisms in tap water and saline, which can lead to wound infection - Staphylococcus aureus, clostridia, pseudomonas and β-haemolytic streptococci. These organisms are the major causes of soft tissue wound infections in the community, where most wounds occur (Brock, 1994). The bacteria were cultured at 22oC and 37oC, according to public health laboratory guidelines on methods of examining water. Four key themes emerged in the articles: cost, practicality, benefits to practice and rationality versus rituality. The seven articles were arranged into three groups: - Group 1: two laboratory rat studies (Moscati, 1998; Reardon and Moscati, 1998); - Group 2: three studies using tap water on human wounds (Dire, 1990; Lawrence, 1997; Towler, 2000); - Group 3: two studies examining the bacterial content of tap water (Riyat and Quinton, 1997; Spencer, 1993). One article from each group was critiqued on the four main key themes. Moscati (1998) researched the use of tap water for irrigating wounds. This US prospective, randomised, blinded laboratory investigation, quantitative study involved inoculating rat wounds with pure cultures of staphylococci, irrigating the wounds with tap water, then culturing for the micro-organism. The study showed that tap water cleansed wounds efficiently and was better than normal saline in removing bacteria from wounds. The researcher concluded that tap water is safe to use on wounds from the data gathered from the rats. The results showed that bacterial infection rates were almost negligible when compared to irrigating wounds with saline (Moscati, 1998). Moscati’s was the first research to look at using tap water to cleanse wounds in vivo and led the way for further study into tap water use for wound irrigation. However, the study had a number of weaknesses. The sample size was only 10 rats, which is too small to have statistical significance (Morse, 1996). While it is acceptable for a controlled laboratory experiment, a larger sample is needed to represent a large population sample (Abott and Sapsford, 1998). The research involved creating linear incisions with uniform depth using a scalpel to simulate wounds. This controlled environment does not equate to a human who has sustained accidental lacerations (Walsh, 1997). The purpose of Moscati’s research was to examine the practicality and benefit to practice of using tap water to cleanse wounds. The researcher suggested that having a designated tap for use in cleansing wounds would have practical benefits for health care professionals and could also benefit patients, as it may reduce the amount of time they spend in A&E (Moscati, 1998). The researcher’s work had a theoretical framework and data analysis, with sound protocol indicative of quantitative studies (Morse, 1996). Moscati’s research must be reviewed with caution, however, as rats’ physiology is different to that of humans. Also, US studies differ in their context and definitions of wound care when compared to UK studies (Morse, 1996). Dire (1990) compared wound irrigation solutions in an American emergency department (ED) in a randomised quantitative study. The researcher cleansed all minor uncomplicated soft-tissue lacerations requiring suturing that presented to the ED in a three-month period. The study had a sample population of 531 patients. Abott and Sapsford (1998) suggest that to be representative of the population a sample size of 1,000 patients is needed. The patients were randomly split into two groups, and half had their wounds cleansed with saline, the other half with tap water delivered by syringe. Dire (1990) used tap water on human wounds and examined the bacterial contamination rate. The theme of this research was on practicality and rationality versus rituality, and it challenged old ideas and philosophies on wound management. The researcher concluded that tap water has a practical benefit to practice, as its use reduced both waiting times in the wound clinic and wound infection rates, and patient satisfaction was high. These results showed that tap water was truly beneficial to practice when compared to normal saline (Dire, 1990). The research suggested that the use of normal saline is a ritualistic rather than evidence-based practice. Dire suggested that practitioners may be resistant to changing their practice and that proposed change should be managed by giving them a sense of ownership of the idea (Cole, 1996). Dire also concluded that using tap water could potentially reduce costs in the department. The main strength of Dire’s research was that its sample population consisted of real patients presenting at the ED with wounds. It was the first research to actually compare use of normal saline versus tap water in practice on humans. Dire (1990) was keen to see tap water used in regular practice but acknowledged limitations to the study which, according to research, shows a solid conceptual framework and acknowledgement of limitations and is a guide for further work (Abott and Sapsford, 1998). The study was not a double-blinded trial because tap water and normal saline have different physical properties, making them distinguishable from one another. The infection rates were low and the study eliminated patients at greatest risk of complicated wound infections. There were also considerable differences in the mean volumes of irrigants used - for example, 1,000ml of saline was used to cleanse one wound versus 500ml of tap water to cleanse another. This difference in irrigation volumes can have a major effect on bacterial numbers in the wound, as it is not known how water physically interacts with bacteria (Angeras, 1992; Lawrence, 1997). The temperature of the tap water and saline differed significantly in the study. The tap water was 37oC while the saline was at room temperature, and these differences could affect wound healing and the rate of microbial growth, as bacteria have different optimum growth temperatures (Brock, 1994). Again this article should be viewed with due attention to the differences in context and definitions between US and UK nursing research and practice (Walsh, 1996). Riyat and Quinton (1997) examined the suitability of tap water in A&E for use on wounds. This quantitative study examined the bacterial cleanliness of water from three designated taps in A&E over an eight-month period by culturing it and examining for contaminating micro-organisms. The research focused on cost and practicality due to the fact that tap water could be a huge cost-saving measure. This study had a large sample size and was representative of a large water sample (Public Health Laboratory Service, 2000). The authors concluded that organisms were not found and that recommendations would be put forward for the use of tap water to irrigate wounds in the department (Riyat and Quinton, 1997). The strengths of this research were that tap water was examined in the A&E department and the study concluded there were no contaminating organisms in the tap water, thus concluding its safety for use. The study also compared the cost of using tap water versus normal saline; the data showed potential cost-saving measures if tap water was used on a regular basis rather than normal saline. This study also was a first to calculate a cost-saving figure for the department. However, the study had recognised limitations: the tap water was never tested on human wounds and did not examine how tap water affects human cells. Tap water provided by water authorities to homes and institutions is tested regularly and is therefore safe to drink anyway, and the study did not acknowledge this. The environment was controlled, as only three taps were designated for study; more taps would need to be used in order to provide a representative sample of taps within the department (Abott and Sapsford, 1998). The study did not investigate the effect of tap water on wounds, so it could not be related to infection or healing rates. Nor did it consider the physiological impact of water on wounds and their surrounding tissue in comparison with saline (Towler, 2000). It is possible that tap water is detrimental to cells and may be inappropriate for routine use. Lawrence (1997) suggests that water may be an inappropriate choice for regular wound irrigation and says that cells survive reasonably well in physiological solutions but are damaged by the addition of water. Riyat and Quinton’s study was typical of quantitative research, having a theoretical framework and sound protocol indicative of quantitative nursing research (Morse, 1996).

After critiquing the seven selected articles, it seems likely that tap water can be used as an irrigant and cleansing agent for soft-tissue wounds. However, the current research on tap water has involved human and rat wound studies and tap water culture studies (Dire, 1990; Riyat and Quinton, 1997; Moscati, 1998). The research is strong, but limitations in current research remain an issue for practice (Towler, 2000). The use of tap water is a cost and practicality issue, and changing current practice is always difficult, as it would seem that the use normal saline is more of a ritualistic process rather than one based on hard evidence (Glover, 1999). Two key conclusions could be drawn from the available research: - The tap water tested was generally agreed to be safe from harmful bacteria and had no contaminating bacteria; - Human and rat models showed a clear benefit in using tap water to cleanse soft tissue wounds, thus concluding tap water is safe for use on wounds (Towler, 2000). The financial benefits were also stated in the studies; tap water can have huge cost-saving potential for A&E departments. In an increasingly cost-conscious NHS this could be a major driving factor for changing practice. However, there were limitations in the methodologies of the selected articles in this critique. Most of the studies measured wound infection rates, but the various researchers did not take into account other factors affecting the likelihood of infection rates and wound progress which would ultimately affect wound infection rates by killing any bacteria in vivo (Angeras, 1992).

Implications for practice
The first course of action people take when they cut themselves at home is to go to a tap and run cold tap water over the wound. If tap water were truly detrimental to wound healing we should have thousands of people coming into A&E departments with infected wounds (Williams, 1996). Saline is probably safer than water, but water tends to be used because of cost rather than physiological considerations (Glover, 1999). It is clear that a study is needed to confirm whether tap water is harmful to human cells at a physiological level. Only then can we confirm whether tap water is truly beneficial to wound management (Walsh, 1996). Several recommendations on cleansing with tap water are based on work that has recognised limitations. The efficiency of techniques and solutions, and their physiological and psychological effects, also require investigation (Williams, 1996). These factors should be considered when determining which cleansing agent to adopt, as should ease of use in a given care environment, the nature of the wound bed and the needs of the patient (Glover, 1999). The costs of different methods, both in terms of financing and potential hazards, should be considered along with appropriate risk management strategies (Walsh, 1997). Impracticalities of any particular technique, such as difficulties in controlling the direction of the cleansing agent and methods of warming, should also be considered (Lawrence, 1997). In establishing evidence-based guidelines, a lack of appropriate research is often a problem. This leaves the procedure open to interpretation and debate, and also to potential litigation if it has not been fully researched. New techniques or procedures to be used in practice must be evidence-based and written into local policy and protocol, as local guidelines can support nurses who are increasingly expected to question their methods and those of others. This is an important issue, as nurses are bound by their code of professional conduct to ensure that their practice is up to date and that others are aware of new practice. Information based on the strengths and weakness of the limited research available may spark enthusiasm for clinical studies that could fill the gaps in knowledge on wound cleansing, as the need to practise evidence-based nursing increases (Young, 1995). A major implication for the use of tap water in wound cleansing is cost and convenience. At present UK hospitals spend approximately £5,000 per year on saline sachets for cleaning and irrigating wounds in A&E departments (Riyat and Quinton, 1997). It should, therefore, be a practical advantage to have easy access to tap water with no need to have saline in stock (Riyat and Quinton, 1997). This would cut the cost by approximately half, making economic and practical sense (Angeras, 1992). In order for tap water to be used safely in clinical practice research needs to be carried out on its effects on human cells in vivo and on bacteria in vivo (Glover, 1999). The effects of the temperature of tap water also need to be evaluated, as does the true practicality of using the taps in A&E departments and the psychological effects on the patient seeing the practitioner run tap water into a container and then irrigate their wound with it (Angeras, 1992). These issues need to be researched before tap water can be used in practice (Small, 2000). Boon (1995) has indicated that research-developed practice is not currently being achieved and argues that nurses continue to support practices that have no sound research base, sometimes continuing with research that has been shown to be detrimental to patients. The research available suggests that tap water is safe from harmful bacteria, and that a clear cost benefit was seen when using tap water to cleanse wounds (Towler, 2000). However, its use as a cleansing agent has attracted interest because it is cheap and freely available, and the subject needs further clinical research to ensure it is beneficial to patients.

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