Next time you’re irrigating a wound, reach for the tap

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altIn the ED, NS is the solution of choice for cleaning wounds. It’s sterile, isotonic, innocuous, readily available and, as far as any of us knows, probably relatively inexpensive.

The Setup: Your next charts are a few minor wounds: a simple fingertip laceration from washing dishes, a toddler with a scalp laceration from a collision with a coffee table, and diabetic senior with a knee laceration while gardening. All three wounds were cleaned with tap water at home prior to coming to the emergency department (ED) and none are actively bleeding.

Your Choices:
1. Clean the wounds with your preferred solution and assess for closure;
2. Clean the wounds with normal saline (NS) and assess for closure;
3. Clean the wounds with tap water and assess for closure;
4. Just assess for closure.

The Evidence:
Fernandez R, Griffiths R. Water for wound cleansing. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD003861.

In the ED, NS is the solution of choice for cleaning wounds. It’s sterile, isotonic, innocuous, readily available and, as far as any of us knows, probably relatively inexpensive. Other solutions have been proposed for this purpose because of their antibacterial properties but these are also potentially tissue toxic. Tap water is the solution of choice for cleaning wounds at home for some of the reasons that we use NS in the ED, innocuous, readily available, and cheap. So why the paradoxical wound cleansing practices? Is it because we believe tap water to be an inferior wound cleansing agent to the bottled concoctions stored on the ED shelves? If so, there must be some evidence to support this notion. Specifically, we should expect to see higher infection rates in those wounds not properly cleaned with ED-stock solution prior to closure.
Fernandez and Griffiths conducted a systematic review to assess the effects of water compared with other solutions for wound cleansing. The included studies were required to have outcomes with measures of wound infection or healing. Most of the identified studies were comparisons of water with normal saline, and tap water with no cleansing. Interestingly, they found that tap water was more effective than saline in reducing the infection rate in adults with acute wounds (RR 0.63, 95% CI 0.40 to 0.99) but not in children (RR 1.07, 95% CI 0.43 to 2.64). Perhaps more surprising was that no statistically significant differences in infection rates were seen when wounds were cleansed with tap water or not cleansed at all (RR 1.06, 95% CI 0.07 to 16.50).

Bottom Line:
This comprehensive search of the literature found no convincing evidence that cleansing wounds with any solution increases healing or reduces infection. This not only contradicts our practice but also our beliefs. However, from a pathophysiological perspective, it makes sense. Introduction of an infectious agent into the tissues occurs at the time of injury. Wound cleansing several hours later is unlikely to have any effect unless it removes remaining debris from a yet uninfected wound. The lower infection rate seen with tap water compared to NS in adults might be due to larger volumes and higher pressure of the former. Regardless, cleaning wounds with tap water, which most of us would do for our children, is also good enough for our patients.

Dealing with Patient Perceptions of Tap Water Irrigation

One issue surrounding the use of tap water for irrigation is a simple public relations quandary: what if patients don’t like it?

First of all, it’s doubtful that patients are aware that we most often use sterile, isotonic, saline to clean wounds. In fact, if the solution were in a kidney basin or some other medicinal-looking vessel, no one would know its origin, tonicity, or sterility. However, asking the patient to stick their injured appendage under the tap is such an obvious degradation in care that it’s sure to elicit complaints.

One simple fix would be for wound cleansing to not occur over a sink (as it does at home). Better yet, there’s nothing preventing the EP from providing a simple explanation for using tap water including the fact that it allows for the delivery of greater volumes at higher pressures and is associated with lower infection rates than cleansing with normal saline.

Another concern might be complaints from patients who subsequently develop an infection following cleaning with tap water. Could they argue that they received inferior care and that was the cause of their infection? The fact is, the bacterial inoculation occurred at the time of injury and the best opportunity to minimize the chance of infection would have been immediately after the injury, i.e. long before the patient was seen by the emergency physician. By the time the patient is seen in the ED, the damage is done. This is why we provide all patients with wound care information about the signs and symptoms on infection regardless of how we managed the wound. As with all other aspects of emergency care, it’s often not so much what care we provide but how we deliver the care that influences patients’ impression of us.

Andrew Worster, MD, MSc, is a member of the BEEM faculty and is an Associate Professor of Emergency Medicine at McMaster University

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