2nd. The "Seton" Type of Wounds. -If a tube closed at one end and pierced with small holes is placed in a "seton" wound whose axis is almost horizontal, liquid readily remains in the wound (Fig. 52). But if the axis of the seton is vertical, the liquid escapes by the inferior opening immediately it is injected. Therefore, sometimes, in these cases a tube wrapped in "tissu eponge" is used. This absorbent fabric (Fig. 37) distributes the fluid over the surface of the wound and keeps it there for a period more or less prolonged.

3rd. Wounds with a Single Orifice. - If the opening is at the "roof" of the wound, the device is simple. A rubber tube bearing a single hole near its blind extremity is introduced to the bottom of the wound (Figs. 50, 53). The cavity of the wound fills up like a cup, and the fluid remains quiescent there until it is displaced by the fresh liquid brought by the tube to the bottom of the wound. The superior opening of the wound should be large enough to allow the liquid to circulate freely. In these cases, "drop by drop" instillation may be used. The liquid continually arriving at the bottom of the wound is constantly being renewed. This arrangement is particularly favourable to rapid sterilisation. Therefore, wherever possible, it is well to transform the wounds with two openings into wounds with one opening, by closing the lower aperture with a tampon.

When the opening of the wound, instead of being found on the anterior aspect of the body, appears on the posterior surface, conditions are altered. If the patient can sleep prone on his stomach, the tube is placed as just described. Otherwise a different device must be adopted. In fact, if the fluid is led to the roof of the wound by a tube which enters by the lower opening, it tends to fall back immediately, under the influence of gravity.

Fig. 53.   Compound fracture of tibia with the opening of the wound on the anterior aspect of the limb; in the seat of fracture is a tube open at the end.

Fig. 53. - Compound fracture of tibia with the opening of the wound on the anterior aspect of the limb; in the seat of fracture is a tube open at the end.

When the wound is a narrow one, a tube sheathed with "tissu eponge" can be used, which may carry the liquid by capillary attraction to the highest regions (Fig. 54). If the wound is larger, several tubes pierced with little holes are introduced and the liquid injected under an adequate pressure. The liquid spurts out over the walls and succeeds in sterilising them, but more slowly than when it can remain quietly in the wound.

Should the orifice occur on the lateral aspect of the body, a certain amount of retention of the liquid can be attained by compresses plugging the orifice. In this case tubes pierced with small holes and closed at one end are used. In addition, the patient should be placed in the position most favourable for retaining liquid in the wound.

Fig. 54.   Wound of the soft parts whose orifice is at the posterior aspect of the limb. Instillation to the roof of the wound by means of a tube sheathed in bath towelling (tissu eponge).

Fig. 54. - Wound of the soft parts whose orifice is at the posterior aspect of the limb. Instillation to the "roof" of the wound by means of a tube sheathed in "bath-towelling" {tissu eponge).

4th. Large Wounds with Several Openings. - Sometimes, if the openings are on the anterior surface of the limb, these wounds can be filled with liquid. Sterilisation is then very simple. But in the majority of cases it is not so. The fluid has a tendency to escape rapidly by the most dependent point of the wound. In addition to lesions of the soft parts, there is often a fracture which makes the wound still more irregular.

Then tubes perforated over a length of 5 to 10 cm. are used, and introduced as deeply as possible into each diverticulum. To fix these tubes in their positions in the central part of the wound, gauze compresses may be used. But it is important to see that the compresses are not packed too tightly, and that they are always separated from the surface of the tissues by a tube (Fig. 55). Avoid placing tubes in the middle of a mass of gauze (Fig. 56). In fractures of the femur, the wound can be kept open by short pieces of rubber tube 3 cm. (about 1 1/4 inches) diameter, which are separated from one another by other pieces of tube placed at right angles. As gravity will not permit the fluid to remain on the surface of the wound, a sufficient number of tubes is arranged so as to moisten every portion of the wound surface (Fig. 55). In the large wound of a compound fracture of the thigh at least 8 or 10 tubes are needed.

Fig. 55.   Irregular wound of the thigh. Two tubes are placed in the wound anteriorly and one posteriorly. These tubes are applied to the surface of the tissues. They are kept apart by gauze packed between them in the opening of the wound.

Fig. 55. - Irregular wound of the thigh. Two tubes are placed in the wound anteriorly and one posteriorly. These tubes are applied to the surface of the tissues. They are kept apart by gauze packed between them in the opening of the wound.

Fig. 56.   The same irregular wound of the thigh. The tubes are wrongly placed. Instead of being in contact with the tissues they are in contact with the gauze which fills the wound.

Fig. 56. - The same irregular wound of the thigh. The tubes are wrongly placed. Instead of being in contact with the tissues they are in contact with the gauze which fills the wound.

5 th. Wounds of the Brain. - The consistency of the brain prevents the application of simple perforated tubes. The cerebral substance, in fact, presses closely against the walls of the tube and enters the perforations. The liquid no longer circulates properly. In the case of cerebral wounds it is therefore necessary to resort to another arrangement, which enables the liquid to circulate in contact with the surface of the wound. The appliance to be used in such cases consists of an external tube, permeable to liquids, and an internal tube of small calibre by which the antiseptic substance is injected. The external tube consists of a very light framework, on which is stretched a thin fabric which has been rendered hydrophilous. This framework Du Nouy constructs of bamboo hollowed and perforated by a thermocautery, while Schmelz and Daufresne make it of thin German silver wire. The diameter of these tubes varies from 1 to 1.5 centimetre, and their length from 4 to 6 centimetres. In the interior of the tube is fixed a small rubber tube about 2 mm. in diameter, which is attached to the framework. This little appliance is fixed in the cerebral wound so that the movements of the head cannot displace it. The meninges are protected by a piece of gauze impregnated with vaselin. The appliance is connected with a special apparatus which instils the liquid drop by drop.

C. Arrangement Of The Tubes According To The State Of Infection. 1st. Fresh Wounds

Fresh wounds nearly always bleed. If tubes pierced with small holes be placed in a wound containing fresh blood, the tube will be filled with it, the blood will coagulate, and the lumen of the tube will be obliterated. It is essential, in fresh wounds, to arrest haemorrhage thoroughly, before arranging the tubes, and to verify their permeability with care, before continuing the dressing. Fresh wounds having no secretion, or very little, tubes sheathed in absorbent fabric may be applied to their surface without inconvenience. For the same reason, gauze is less harmful on fresh wounds than on wounds which are suppurating.

2nd. Suppurating Wounds. - The presence of pus on a wound is an indication that tubes surrounded by absorbent tissue may not be used, because this fabric immediately becomes saturated with pus. For the same reason "wicks" and gauze compresses are used as little as possible, and tubes multiplied. Gauze may be used at the orifice of the wound. But all the diverticula should contain tubes and not gauze. It is advisable to have the tubes more numerous than in a fresh wound of the same dimensions.

Fig. 57.   Testing the permeability of a conducting tube at the time of dressing.

Fig. 57. - Testing the permeability of a conducting tube at the time of dressing.

D. Testing The Working Of The Tubes

Before the dressing is applied, the permeability of the tubes and their perforations should be tested (Fig. 57), also the manner in which the various regions of the wound are receiving their share of the antiseptic liquid. This test is to prove that the tubes have not become plugged with blood-clot, and that the distribution is taking place evenly over the whole surface. Further, it shows what quantity of liquid will be needed to fill the wound completely, or to moisten the entire surface, should its position not allow of its being filled.

The nurse should be present at this testing, which will also show her how to control the flow of liquid in the wound without wetting the patient.