An essential point of the method is the prolonged application of the antiseptic. This principle seems to have been neglected as much as the preceding. Although experiments in vitro have shown that microbes, to be destroyed, must be immersed in the antiseptic solution for some considerable time, yet people persisted in believing that, under the much more unfavourable conditions of the clinic, sterilisation of a wound could be obtained by brief contact between bactericidal substance and microbes. That is why so many surgeons still remain loyal to the rite of washing over a wound with an antiseptic liquid.
They imagine that if a liquid has flowed over the surface of a wound for four or five minutes, often much less, that wound will become sterile. It is certain, however, that to obtain any action the antiseptic must remain on the wound for a much longer period.
In the following clinical experiments it was sought to discover what should be the length of time for the application of the hypochlorite.
In the first place, the influence of hypochlorite applied as is usual in a wet dressing was examined. Upon surface wounds, whose bacteriological condition was known, compresses were placed soaked in a 0.5 per cent. solution of hypochlorite. The next day the number of microbes had not undergone any appreciable change. Gauze "wicks" soaked in hypochlorite were also introduced into deep wounds. At the end of twenty-four hours, the surface of the compresses yielded a large number of microbes.
The insufficiency of the technique usually employed was thus demonstrated. Next, the length of time during which hypochlorite was present in the wounds was lengthened by soaking the dressing with the antiseptic three times a day. In most cases the "smears" showed a marked lessening in the number of microbes; but the wounds more deeply infected showed no change. On one small wound dressed three times a day with hypochlorite, the number of microbes did not diminish. At the end of a week of this useless treatment, a small quantity of hypochlorite was injected hourly over the surface of the wound, under the compresses. All the microbes disappeared (Fig. 34).
A large number of similar experiments showed that, in surface wounds, the infection did not resist instillations of hypochlorite every two hours during one or two days. In deep wounds, diminution in the number of microbes came about more slowly, even under the influence of frequent instillations of hypochlorite. Daily examination of the " smears," made from the discharges from different regions of wounds of the soft parts, more or less irregular, showed that microbes often took four or five days to disappear. In severe lacerations of the soft parts, or in compound fractures, the application of the hypochlorite had to be continued usually eight, ten, or fifteen days before sterilisation was achieved.
Fig. 34. - Necessity for prolonged contact between the antiseptic and the wound. Highly infected atonic wound treated up to Nov. 26th by applications of hypochlorite three times a day. No diminution in the number of microbes. Nov. 26th, Dakin's hypochlorite was applied every hour. Sterilisation was attained Nov. 29th. (00 denotes infinity. - Trans.)
In wounds complicated by splintered fractures it was sometimes impossible to get complete sterilisation. Generally the persistence of infection was due to the presence of a foreign body, projectile, splinter, or shred of clothing. When the foreign body was removed, sterilisation came about. Disinfection of deep wounds always takes longer than that of surface wounds. With the technique now in use, compound fractures are sometimes disinfected in five or six days. As a general rule, sterilisation requires ten, fifteen, or twenty days, or even more, if it is a question of a compound fracture of the thigh.
It will be well to inquire why the duration of application of the antiseptic has to be longer for compound fractures with large wounds, than for surface wounds.
We have often seen surface wounds yielding many microbes become sterilised in forty-eight hours. The tardiness of sterilisation in irregular wounds appears to be due to the presence of diverticula into which the liquid does not penetrate, and where microbes swarm, or to the presence of sphacelated tissues which shield the microbes from the attack of the antiseptic. However, in surface wounds, with sphacelated tissue, sterilisation is brought about more quickly than in large and irregular wounds. Therefore it is probable that imperfection of technique alone renders necessary a prolonged application of the antiseptic. There is not, in fact, any theoretic reason why a large and irregular wound should sterilise more slowly than a small wound with even walls? But it is much more difficult to make the liquid penetrate all the irregularities of a deep wound than it is to bring it into contact with the entire surface of a smooth one.
The duration of the application of hypochlorite in deep wounds will lessen when it becomes possible to apply the antiseptic continuously to the entire surface of the wound. Our technique is still too clumsy, and the methods of distributing the liquid in use to-day do not succeed in placing every portion of a large wound simultaneously under the influence of the bactericidal substance. It is quite probable that different portions of an extensive wound are sterilised successively, for the bacteriological examination shows that after the lapse of several days certain regions of a wound are sterile, whilst others still continue to harbour microbes. Besides, rapidity of sterilisation increases to a certain extent with the quantity of liquid employed, that is to say, it depends on the extent of the surface of the wound which is acted on by the liquid. It is permissible to believe that improvements in technique will lessen the period during which antiseptic instillations will need to be employed, but it is unlikely that this period will be cut down to less than twenty-four hours.