Garcia Torres V., Gomez Bajo G., Herruzo Cabrera R.

Burn Unit, Department of Plastic Surgery, La Paz Hospital, Madrid, Spain

SUMMARY. A study was undertaken to determine not only the effect of a hydrocolloid dressing on the healing of small deep dermal and full-thickness wounds but also its relation to other factors such as age, mechanism, localization and, especially, bacterial colonization/ infection. Fifty-five patients were studied in relation to subjective sensations (pain, discomfort, odour), epithelialization phenomena and relative rates, bacteriological surveillance by semiquantitative cultures, and sequelae.

There is an endless series of synthetic and biosynthetic dressings which are continuously recommended for use in topical treatment of burn wounds. Thorough knowledge of even a part of them would require full-time work in their study and experimentation.
Among all these new dressings, we have used in our Burns Unit at La Paz Hospital a semipermeable hydrocolloid dressing, which owed its absorbent properties to carboxymethy1cellulose. Various studies (2) have reported an improvement in healing rates when using this kind of dressing compared to classical techniques. Its effect seems to be due to its occlusive properties, as it creates a special microclimate that reduces healing time, with better cosmetic results and less discomfort and pain sensation (1, 2, 3).

Sheets of this dressing consist (2) of a semipermeable polyurethane film coated with a flexible elastic mass (made from a styrene-isopropene block copolymer together with polycyclopentadiene dioctyladipate) and containing 42% sodium carboxymethylcellulose (NaCMC) as the principal absorbent (Figs 1-9). The application of these sheets was performed under aseptic conditions after washing the wound carefully and covering the area to be treated with a gauze impregnated in clorhexidine digluconate for five minutes. The frequency of change ranges from 2 to 4 days, with an average of 3.5 days. The mean number of applications was 4.41 (from 2 to 10) (Table 1).

Fifty-five consecutive patients with small-size burns (range: 0.1 to 10% TBSA) treated at our Bum Unit (in-patients and out-patients) between June 1992 and January 1993 were included in the study. For each patient age, sex, cause of injury, total body surface area burned, depth of injury, localization, previous pathology, size of area treated with the dressing, previous treatment and days post-bum when dressing was first used wore recorded. Bacteriological surveillance was performed by wound semiquantitative cultures (4) before and after each application of the sheets. Subjective sensations of the patients were also recorded: pain, discomfort, odours. Patients were followed up after discharge in order to determine shortand medium-term cosmetic and functional results and scar quality.

Wound healing was achieved in 50 patients. The other five patients needed autografts to cover their wounds. Three of the patients who needed surgery were over 70 years old, four suffered from previous vascular diseases and one suffered a high-voltage electrical injury in the foot causing a full-thickness burn involving tendons and bone.
The dressing proved to be well accepted by the patients. Fourteen patients reported slight pain (Table 1) after application; 36 felt no discomfort, which was severe in only four patients; and 15 perceived slight bad odour (strong in two cases). Surprisingly, discomfort and pain had no relation to positive wound cultures and only a slight correlation to odour.
The average length of time before complete healing was 16.08 days (range: 8 to 30 days). When previous wound cultures were negative, the epithelialization time was shorter (14.46 days) than when they were positive (18.94 days). When wound cultures were negative after application of the sheets, healing was achieved earlier (15.04 days) than when they were positive (17.00 days).
The analysis of epithelialization quality related to colonization/infection of the wounds shows similar results. When previous cultures were negative, excellent results were obtained in 71.85% of the patients, and when positive in 55.55%. When organisms were isolated after application of the sheets, excellent results were obtained in 60.71% of the patients, compared to 71.42% in whom no organism grew.
The microbiological data are shown in Tables H to VIII. Previous wound cultures were sterile in 63.63% of cases. On day 8 after initiation of treatment with this hydrocolloid (second control), micro-organisms were isolated in 57.70% of the cultures. At the fourth control (day 16), micro-organisms were isolated in only 6.13% of cases. The most frequent micro-organisms were S. aureus (peak incidence (P1) 36.53%) and S. epidermidis (PI 24.98%). Gram-negative bacteria (E. Coli, Proteus, Pseudomonas) showed a very low incidence.
Medium-term results (6 months) were predominantly good. Pigmented scars appeared in 23 patients (only five with very obvious pigmentation). We found no keloids in our patients and only two of suffered from hypertrophic scars. Twenty patients developed cosmetic sequelae which were severe in only one case; seven patients suffered slight functional sequelae and one developed a serious problem, suffering mutilation of the foot after a high-voltage electrical injury.

Table II Bacteriological surveillance control after second application Table III Bacteriological surveillance control after second application Table IV Bacteriological surveillance final control Table V Bacteriological surveillance Table VI Bacteriological surveillance positive cultures Table VII Bacteriological surveillance positive cultures

Discussion

We have tried in this study to assess the benefits of a hydrocolloid dressing after using it in our Burn Unit at La Paz Hospital for a period of six months.
We believe that the best method for treating small deep den-nal and full-thickness burns is early surgical debridement and immediate closure with autografts. Nevertheless, in certain circumstances, with small-size burns, if surgery cannot be performed because of previous pathology, anaesthetic contraindication or -not infrequently - because the patient refuses any surgical procedure, we consider that this dressing is a good alternative.
This dressing is mainly indicated for deep dermal burns and sometimes for full-thickness bums. We have noticed that post-application pain, discomfort and bad odours are very infrequent, which makes it better accepted by the patient than other topical therapies. We have also noticed that epithelialization time is shorter than that necessary with classical techniques, in agreement with previous reports (2).
What we have not seen in any previous study is a bacteriological surveillance of the wound. These reports (5, 6) were based on clinical controls, which found no macroscopic evidence of infection. When we tested the microbiological state of these wounds, by means of seniiquantitative cultures, we found that in spite of the absence of antimicrobial properties in this dressing infection was no more frequent than that expected when using other antiseptic agents. Epithelialization was obviously achieved earlier when no wound infection/colonization appeared. These results may be related to the improvement of healing time.
To sum up, the careful use of this dressing under aseptic conditions offers a very good alternative in the treatment of small-size deep dermal and full-thickness bums.

Fig. 1 Self-inflicted chemical bum in an attempt to remove a tattoo. Fig. 2 Surgical removal of the eschar Fig. 3 Application of carboxyrnethylcellulose sheet. Fig. 4 Control after 10 days of treatment.

 

Fig. 5 Final result

 

Fig. 6 Contact burn. Thirty days of evolution in other hospital. Fig. 7 Application of carboxymethycellulose sheet Fig. 8 Control after fifth application Fig. 9 Final result.

RESUME. Cette étude détermine non seulement l'effet d'un pansement hydrocolloïdal sur la guérison de petites lésions dermiques profondes et à toute épaisseur mais aussi sa rélation à d'autres facteurs comme l'âge, l'étiologie, la localisation et, particulièrement, la colonisation/infection bactérienne. Les auteurs ont étudié 55 patients, en considérant les sensations subjectives (douleur, malaise, odeurs), les phénomènes d'épithélialisation, le contrôle bactériologique par les cultures sémiquantitatives, et les sequelles.