SUMMARY. In this article the authors discuss the problem faced by physicians when trying to use moisture-retentive dressing in pressure sores (decubtus ulcers). First, they report the results of an in vitro study using a new model of experimental wound (radio-isotopic investigation) that assesses the release of Ringer's solution from interactive dressings continually during fourteen hours. Second, they perform an animal experiment that assesses the incidence of wound infection in defects treated conventionally or using interactive dressings. The defects treated with interactive pads had lower incidence of wound infection, and the process of wound healing was rapid. Finally, the authors discuss their experience in four paraplegic patients with decubitus ulcers where they used moisture-retentive dressing on ulcers and on the surrounding intact skin before surgical procedure to detect the possibility of maceration of healthy skin. Histological evaluation was performed in order to find microscopically changes after moisture healing. The changes of healthy skin were not significant after treatment of moisture-retentive dressings.
In dem Beitrag wind die Verwendung den cur Wundenheilung benutzten Binden im feuchten Milieu des Dekubitus diskutiert. In dem ersten Tell des Bell women die Ergebnisse einer Studie zum neuen Wundenmodell beurteilt. Die kontinuierliche Lbsung den radioaktiv markierten Ringer-Lbsung aus den interaktiven Binde innerhalb 14 Stunden wurde beobachtet. In dem zweiten Tell wird eine experimentale Studie beschrieben. Bel einem Tier wurde das Vorkommen den Infektion in den Wunden wahrend einer konventionellen and Feuchttherapie beobachtet. Bei den durch interakfiven Binden bedeckten Defekte kam die Infektion in den Wunde weniger vor and den Heilungsvorgang lief schneller ab. In dem letzten Ted des Befrages wenden die Ergebmsse einer Unto, suchung von vier Patienten mit den Paraplegie vorgestellt. Bei diesen Patienten wurde auf die intakte Haut in den Umgebung des Dekubitus eine interaktive Finale appliTen. In den histologischen Hautproben wurden die durch feuchte Heilung verursachte hatopathologische Veranderungen betrachtet. In den intakten Haut wurden keine signifikant unterschiedliche Returnee bemerkt.
Key words: moisture wound healing, interactive dressing, model of experimental wound, pressure sores, wound infection, histological evaluation of human skin
Throughout the history of mankind people have made great efforts to stop bleeding and treat wounds without pain, and they have also had to deal with the consequences. Wound healing is a complex process involving cellular, immunologic and hormonal components interacting to result in a healthy wound. When the process is disturbed, patients require frequent medical care and have a low quality of life as a result of the chronic wounds. Therefore wound healing is a problem facing all physicians, especially surgeons (5).
In our study we used a moisture-retentive dressing TenderWet (TW) produced by Paul Hartmann company. The dressing is an interactive therapy that has a unique self acting rinsing mechanism. TW is a multilayer wound dressing pad and exists in two forms, TW12 and TW24, both of which are available in various shapes and sizes (2).
For the last eight years moisture-retentive dressing has been widely used in our Department of Burns and Reconstructive Surgery in the treatment of deep dermal burns, chronic wounds and other skin defects. The therapeutic effects of this wet dressing are very promising. On this basis, we designed some experiments to evaluate this therapy scientifically.
The aim of this study was to explore the influence of interactive dressings on wound healing. We were seeking answers to three main questions:
In vitro study
The aim was to monitor continuous release of Ringer's solution from the interactive dressings. We used in vitro a new model of experimental wound (cellulose foam) that coincides with the clinical condition (Fig. 1). The sponge served as a bed for the interactive dressing. The size of the sponge was 40x40 mm square, and it was fully saturated with human plasma (10 ml).
Twenty samples of interactive dressings (TW) were soaked with 10 ml of Ringer's solution with radioactive substances 99'Technecium (activity 50 megaBq). All samples were monitored by Gama camera (MB-9200) (Fig. 2). The interval of radioactivity measurement was every six minutes, and monitoring of radioactivity leakage from every dressing covered fourteen hours. For evaluation of the samples a computer program (DIAL program) was used, and every value was registered onto graphs. We formed curve decreasing of radio-isotopic activity from interactive dressings.
<% immagine "Fig. 1","gr0000018.jpg","In vitro study. A now model of experimental wound.",230 %> <% immagine "Fig. 2","gr0000019.jpg","Evaluation of results from Gama camera using computer program.",230 %> <% immagine "Fig. 3","gr0000020.jpg","Animal experiment. The defects on the left side were covered with conventional dressings, those on the right side with the interactive dressings..",230 %> <% immagine "Fig. 4","gr0000021.jpg","Rebandage and monitoring bacterial infection.",230 %>Animal experiment
In the animal experiment we compared two types of dressings (conventional and interactive) and evaluated infection in experimental wounds of pigs. Full-thickness skin defects were produced on the backs of four pigs, eight per pig. We evaluated thirtytwo defects. Each defect was a circle (diameter 40 mm). the same extent as the dressing pad. The defects on the left side of each pig were covered by impregnated gauze and a wound dressing moistened with 17, Peracetic-acid solution (Fig. 3). The wounds on the right were covered with the interactive dressing (TenderWet activated by the addition 10 ml of Ringer's solution). We changed each dressing daily and monitored bacterial infection on the wound surface at regular intervals (every third day). For each site of injury we evaluated the presence and quantity of various bacterial strains (Fig. 4), and the mean size of the non-healing area using planimetry. The animal experiment was performed over fourteen days.
Clinical study
In the prospective clinical study we followed the microscopic changes in human epidermis and dermis after application of interactive dressing, paying special attention to the possibility of maceration of healthy human skin. The study was performed in four paraplegic patients with pressure sores (decubital ulcers) prior to the operation, where both healthy skin to be incised and painless (insensitive) chronic wounds were present. We used moisture-retentive dressing (TenderWet 24, 75 x 75 mm, activated with 30ml of Ringer's solution). The Ethics Committee of Masaryk University and University Hospital Brno approved this clinical study. The patients were comprehensively informed of the study and signed the informed consent.
The patients with pressure sores were prepared for radical operation - excision of decubitus ulcer and closure of their wounds with musculocutaneous flaps.
Skin samples for histological evaluation in each patient were taken from:
A small wedge excision (20x10 mm) - biopsy was performed during the operation of the ulcer (sample I). Three excisions of healthy skin from the site of incision were made in order to raise the flap and treated previously for 48 hours (sample II), 24 hours (sample 111) and 0 hours (sample IV) with TW24. All samples were divided into four pieces for different histological staining.
Histological examination of all samples was performed using four methods:
Positive control was created by taking three pieces of excised healthy human skin from the fifth patient submerged in Ringer's solution for 24, 48 and 72 hours, specimens were kept at +4 °C. These samples respectively featured as a positive control of skin maceration.
In vitro study
We observed gradual release of Ringer's solution (with radioactive substances 99"'Technecium) from each interactive dressings over fourteen hours. We registered the result of all experiments onto graphs after evaluation using a computer program. We formed a curve of continuously releasing radioisotope activity from dressings. Courses and characters of all curves show long-term moisturising of experimental wounds (Fig. 5).
<% immagine "Fig. 5","gr0000022.jpg","The curve monitoring of radioactivity leakage from in teractive dressing.",230 %>Animal experiment
We detected significant quantities 10" Colonyforming units/gram (CFU) of Escherichia Coli and Mebsiela spp. at the deep layers of gauze and 105 CFU/gram of Staphylococcus aureus on the surface of all of the wounds bandages with conventional dressings. We also noted a difference in the healing process (Fig. 6). These wounds were covered with dry granulation tissue, the healing process was slower, and the mean non-healed area was 2112.3 mm', i.e. 42 %.
<% immagine "Fig. 6","gr0000023.jpg","Fourteen days after surgical procedure. Evaluation of healing process. The defects orthc,ightsidc,c,eb-ded with odd numbers. The view before planimetry measurement.",230 %>In contrast. the wounds treated with interactive dressings had a lower incidence of surface infection 101 CFU/gram of Staphylococcus aureus and 10' CFU/gram of Escherichia Coli and Klebsiela sop. in the central part of dressings. There was rapid re-epithelization from the wound margin, the wound bed filled up with healthy granulation tissue, and the mean non-healed area was 1706.9 mm', i.e. 34 '/,. Statistical analysis showed that the interactive dressings were significantly superior to conventional bandaging (p=0.037. p<0.05), (Tab. 1).
<% createTable "Table I ","Comparison of healing with the two types of dressings",";Subject §1,2§ Non-healed area with conventional method §1,2§ Non-healed area with interactive dressings ; Difference between the two types of dressings (mm2)@; ; (mm2); (%); (mm2); (%)@;1; 1930.6; 38.4; 1351.0; 26.9; 579.6@;2; 2703.2; 53.8; 2283.3; 45.4; 419.9@;3; 1831.0; 364; 1747.2; 34.8; 83.8@;4; 1984.6; 39.5; 1446.2; 28.8; 538.4@;Mean;2112.3; 42.0; 1706.9; 34.0; 405.4","",4,300,true %>Case report No. I
A 69-year-old female presented with sacral decubital ulcer. The wound was treated using a dressing which containing 1%, peracetic acid. Three days before operation we applied interactive dressings on the wound surface and intact skin (sample I). Every day we changed the dressing and added TW on the other place of intact skin (sample II, sample III), (Fig. 7). During surgical procedure four biopsies were taken for histological examination (sample IV from intact skin without any contact with interactive dressing). (Fig. S). The ulcer was closed by musculocutaneous flap (m. gluteus maximus), (Fig. 9) Fourteen days after the operation the patient was healed and transferred to the geriatric department.
Case report No. 2
A 48-year-old paraplegic male was admitted to our department with large trochanteric ulcers. The patient underwent some operations for sacral and bilateral trochanteric decubitus. The reason for recurrence was bone deposit on the proximal end of right femur (Fig. 10). Application of TW according to the experimental schema (see material and methods) (Fig. 11). During surgical procedure the bone deposit was removed. and after debridement of devitalised tissue the defect was closed with musculocutaneus flap (Fig. 12). Post operative time was without serious complications.
<% immagine "Fig. 7","gr0000024.jpg","The view of sacral ulcer. The .scheme of application of interactive dressings.",230 %> <% immagine "Fig. 8","gr0000025.jpg","Taking four histological samples",230 %> <% immagine "Fig. 9","gr0000026.jpg","Surgical procedure, clore of defect by nmsculocutanc ue flap (glut. max.)",230 %> <% immagine "Fig. 10","gr0000027.jpg","The vie„ of yressure.sore-largetrochantericulcer",230 %> <% immagine "Fig. 11","gr0000028.jpg","Application schema of interactive dressings on deeu bitus and intact skin",230 %> <% immagine "Fig. 12","gr0000029.jpg","Surgical procedure-closure of the defect by muscu locutaneusflap",230 %> <% immagine "Fig. 13","gr0000030.jpg","HE staining (magnification 16x). Healthy skin after application of interactive dressings during 48 hours. Histological view papillary et reticular de, mis, stratum basalc and clear vacuoles in cytoplasm 7sof inside stratum ,limosum. thin layer of'squamous epithelial cells",230 %> <% immagine "Fig. 14","gr0000031.jpg","HE staining ~magruYicaiion 16x) Human intact skin submerged in Ringer solution for seventy-two hours (a positive control of maceration). Papillxr layer of decade, stratumbasale, stratum spino.sum contains cells with clear vacuoles m cytuplaem. Stratum disjunctum on the surface",230 %> <% immagine "Fig. 15","gr0000032.jpg","HE staining (magnification 16x) Intact skin (without treatment of interactive dressings). Histological view: reticular and papillary layer of dermis with blood vessels, base ment membrane, layer of epidermis-stratum basale, spinosum and curneum",230 %>Histological evaluation
A picture of normal healthy human skin was present. We did not see any histological changes in healthy human skin after treatment with interactive dressings. Actually, the only interesting findings are small vacuoles. which are present in stratum spinosum mainly in samples treated with moistureretentive dressings (Fig. 13) and also in samples submerged in Ringer solution (positive control skin samples) (Fig. 14) and almost absent in the skin without any dressings (Fig. 15).
Winter and colleagues described the benefits of moist wound healing for the first time in 1962 (1).
They reported that moist wound healing enhanced the rate of wound re-epitelization. Since then the use of moistureretentive dressings has been shown in several other studies (3, 4, 7) to provide the optimal environment for wound healing, accelerate the healing process and promote tissue growth.
We divide dressing according to the influence on the wound surface into three categories:
During our experimental work on animals we have observed very effective debridement of the wounds after application of interactive dressings. The wound bed tends to form a healthy granulation tissue. The healing process in these wounds is rapid and uncomplicated. The interactive dressing absorbs bacteria. detritus and bacterial toxins. It facilitates softening and debridement of necrotic tissue, helps to maintain physiological temperature during wound healing, the reducing the need for dressings, and supports wound epithelization from the edges as well as its contraction.
Summarising the histological documentation, one can see very small differences in the histological picture in all the samples. One point of considerable interest is the presence of small vacuoles in stratum spinosum, mainly in samples treated with interactive dressing and also in samples submerged in Ringer solution. There are three explanations possible:
The results of our experimental work seem to suggest conclusively that a moist wound environment is more effective in facilitating wound healing and reducing bacterial strains than the conventional methods.
In our prospective clinical study no damage to human skin was detected which could be caused by treatment with interactive dressings for either 24 or 48 hours. The innumerous intracellular vacuoles found in stratum corneum are either an artefact or a sign of slightly higher content of water in epidermis indicating harmless hyperhydration rather than a significant maceration of the skin.
Acknowledgements
The moisture-retentive interactive dressing (TenderWet) used to treat the patients and domestic pigs described in this paper was purchased from IVF Schaffhausen, Switzerland and Paul Hartmann AG., Heidenheim, Germany. None of the authors has any financial interest in its use.
Address for correspondence:
J. Koupil
Department of Burns and Reconstructive Surgery
Faculty Hospital Brun
625 00 Bran
Czech Republic
E-mail: jkoupil@fhbrno.cz