54.1 Preventing infection—the wound toilet

A wound can heal in two ways. Either it can heal by first intention, quickly, with no sepsis, and with the minimum of scarring. Or, it can heal by second intention, slowly by granulation, perhaps with the discharge of pus, and eventually with much scarring. Unfortunately, when you see a wound you often will not know what it is going to do. If you sew it up immediately by primary suture, will it heal elegantly by first intention? Or will it break down and pour out pus?

Answering this question depends on understanding the timing of events as a wound heals after a major injury in a shocked patient. During the first few hours the body’s first priority is to maintain the circulation to the patient’s brain (53.1) at the expense of that to his less essential organs, including his skin and bones. Meanwhile, the bacteria which have entered his wound have their own time scale. What they do depends greatly on the nature of his wound, and on how much foreign material and dead tissue there is in it, especially dead muscle. Even if there is much debris and dead tissue and conditions favour them, they multiply little in the first 6 hours. From 6 to 12 hours they are beginning to multiply, but after 24 hours they are multiplying fast. If infection is going to occur, it will be established after 24 hours. By about the third day, the body’s priorities will have changed, the blood supply to the patient’s wound will have increased, and it will be in the ideal state for healing and resisting infection.

You will see the following kinds of wound, depending on the time since the injury, its severity (particularly the amount of dirt, dead tissue, and especially dead muscle present), and the patient’s ability to overcome infection.

(1) A wound which presents within the first 6 hours. The challenge before you is to remove all damaged tissue and the dirt by toileting the wound before the bacteria in it can start multiplying. Even a few hours can be important, so don’t delay.

(2) A wound presenting at any time with obvious systemic or local signs of infection. These signs don’t start for 6 hours, and become more serious the longer the delay. Bacteria are now established in the dead tissue, and are passing into the lymphatics around the wound. If you do too vigorous a toilet, you may spread the infection further, so treat the wound as an infection. Gently remove any slough without disturbing the surrounding tissue, drain the wound, or pack it with dry gauze, or apply a hypochlorite (’Eusol’) dressing, and give the patient an antibiotic. This is the delayed wound toilet described in Section 54.5. A day or two later, when you have controlled his infection, you may be able to complete the toilet of his infected wound.

(3) A wound which is more than 48 hours old, without systemic or local signs of infection. By this time the patient has overcome any bacteria that might have been present, so you can safely toilet his wound as vigorously as is necessary.

(4) A wound with much dead tissue in it, which presents between 6 and 48 hours after the injury without any obvious signs of infection. Deciding what to do can be difficult. Should you do a vigorous toilet, or should you merely drain it? The wisest course is to treat it as (2) above and do a gentle toilet, repeating this later if necessary.

Time is critical. If a patient has a severely contaminated wound, he needs a wound toilet, immediately he reaches hospital. Delay is inexcusable. Grossly contaminated wounds and crush injuries are acute emergencies. Every hour’s delay makes his chances of an uncomplicated recovery less likely.

After you have toileted a wound, when should you close it? This mostly depends on the interaction of three factors: (1) How much dead tissue or debris there is inside it. (2) Where the wound is. You can close most wounds of a patient’s face or hands by immediate primary suture. But in the shaded areas in Fig. 54-1 the risk of infection, and particularly gas gangrene makes immediate primary suture unwise, especially if a wound is heavily contaminated. (3) The time since the injury. You may be able to close a wound immediately if you have toileted it within 6 hours of the injury, before the bacteria in it have started to divide. But if there is much dead tissue or debris, you would be wiser to leave it for delayed primary suture. If you are in any doubt, leave a wound open for delayed primary closure on the third day. The patient will have overcome his infection, and his tissues will be in their most active healing state. His wound will heal by first, not second intention, just as it would do if you sutured it immediately, but it will heal much more certainly.

Figure 54.1: WHERE TO FOLLOW THE RULES RIGO­ROUSLY. The rules are: (1) do a thorough wound toilet, (2) close the wound by delayed primary suture whenever you are in doubt. The darker the area in this figure, the more important these two rules are. Kindly contributed by Peter Bewes.

The common mistakes are: (1) Not to do an adequate wound toilet. (2) Not to leave a wound open for delayed primary closure. Neglect of these things delays wound healing, and may cause traumatic osteomyelitis, or the need for an amputation. There is seldom any indication for suturing any wound in the interval between 6 hours and the third day, with the possible exception of clean knife wounds.

There are two parts to a wound toilet: (1) Do a social cleaning of the wound and the skin round it to wash away bacteria and foreign material. Use soap, a soft nail brush and plenty of water poured in, or saline. You may need many litres, a few spongefuls are not enough. (2) Do a surgical toilet with a scalpel to remove damaged tissue, so that the patient’s inflammatory response can get to every part of it. If his wound is large and dirty, toileting it may take you an hour.

Adapt the way you toilet a wound to its severity and its site. Only the severest and most disadvantageously sited wounds in Fig. 54-1 need all the measures described below. At one extreme, a recent clean, incised, knife wound of the scalp needs a social toilet only, and no surgical toilet. At the other extreme you will need to remove much dead muscle from a grossly contaminated wound. Don’t hesitate to use a nail brush; it is the best way to remove ingrained dirt, such as occurs when a limb has been dragged along a road.

If there is any contamination, a wound toilet is necessary. For example, if a patient treads on a nail, don’t merely give him antibiotics and hope for the best. Instead, excise the puncture wound, curette the track, and leave it open.

You will need these methods: (1) The immediate wound toilet described below, for all wounds which present early, and for those which present late without infection. (2) Immediate primary suture, which can follow it if the indications are right (54.2). (3) Delayed primary closure or skin grafting at 3 days, which should be the rule for severe wounds (54.4), especially if they are contaminated or in dangerous areas. (4) A delayed wound toilet for infected wounds which present late (54.5). (5) Secondary closure, usually by skin grafting, for wounds which are starting to heal by granulation at 10 days (54.6). (6) A method for chronic wounds which are months or years old (54.7).

You cannot prevent bacteria entering a wound at the time of the injury, but you can prevent them entering a wound in the hospital. A common error is not to toilet and suture wounds in a sterile manner. So make sure you do this, and your staff do so too.