Dilution is the solution to pollution. You’ve all heard this one right? Irrigation is critical in decreasing the incidence of wound infections. Small foreign bodies in the wound are a nidus for bacterial growth. Let’s take a look at some common questions surrounding wound irrigation that will help you as you encounter various lacerations in the Emergency Department.

What solution should I use to irrigate?

In short, probably anything that you have on hand is fine. Some options include;

Sterile 0.9% saline
Tap water
Dilute povidone/iodine solution

Obviously tap water is cheap, and at least animal models showed that good decontamination was achieved. Saline is a little more expensive, but not by much. Hydrogen peroxide has been associated with air embolism – so don’t use it. In a meta analysis of wound irrigation in adults Fernandez et al noted that “there is no evidence that using tap water to cleanse acute wounds in adults increases infection and some evidence that it reduces it. However there is not strong evidence that cleansing wounds per se increases healing or reduces infection. In the absence of potable tap water, boiled and cooled water as well as distilled water can be used as wound cleansing agents.” With some earlier studies (at least in adults) quoting a 5% infection rate it is important to just irrigate with something rather than not irrigate at all.

What is the right technique?

First of all, you should always assure that you have effective local anesthesia. This is achieved via topical LET, intradermal lidocaine or regional nerve block. Don’t irrigate a wound that isn’t numb – that’s just mean.

High pressure irrigation is most appropriate for wounds that are very contaminated and devitalized. The exact amount of pressure has actually been studied, with Singer et al. measuring pressure dynamics of 250 mL boluses of normal saline delivered using various syringes and a needle attached directly to an IV fluid bag. Ultimately they recommend using a 35-mL syringe or a 65-mL syringe with a 19 gauge needle achieve at leave 25 to 35 psi.

For most other wounds very high pressure irrigation may injure tissues. 5-8 PSI is sufficient, which is generally achieved with a 30 to 60mL syringe with or without a needle attached. Pronchik noted that in an animal model pressures between 5-8 psi were OK at decontaminating staphylococcus wounds.

You should definitely use a splashguard (seen below) as well. This helps avoid splashing yourself or the patient excessively and is good practice in any wound. The splashguard is held against the skin, and the solution will exit the outlet holes (if present on your model) as you irrigate. Don’t push too hard – you don’t need to indent a circle into the skin. Administer the irrigation in a pulse-like fashion, pushing the plunger repeatedly, delivering 1-2mL per squirt. This creates a washing machine like effect within the wound.

How much volume should I use?

In general enough to make sure the wound is clean. A good rule of thumb is at least 100mL per centimeter of laceration. You may need more for grossly contaminated wounds. A 1cm face wound for instance should be irrigated until visibly clean – aim for 100-200mL total volume.

Do I really need to irrigate every wound?

I would say yes for any open wound. You don’t need to irrigate an abrasion – just clean it off of course. There is some evidence that suggests that not all uncontaminated wounds need to be irrigated – see Hollander et al for more.