An Experimental Study On Vacuum Sealing Drainage Combined With Ozone Water Flushing In Care Of Infected Wounds

BackgroundWith the rapid development of social economy, all kinds of incidents and the natural disaster such as earthquake, tsunami, mud-rock flow frequently occurred. Open injury of limbs is increasing, and often lead to large area defect of skin and soft tissue and the bones, muscles, blood vessels and other important structure exposed for great violence. Wound is often polluted seriously, although after thorough debridement and anti-infective treatment timely, the infection still often occurred and even because serious infection can’t control and force to amputation, it will bring heavy burden to patients and society. For a long time, because the unreasonable using antibiotics, it produced the super bacteria as a representative of drug-resistant bacteria. At the same time the local blood circulation is poor because large areas of skin soft tissue defect or vascular injury for severe trauma and intravenous antibiotics sometimes can’t form effective bactericidal concentration in local. One of the important links for prevention infection for open wound is thoroughly debridement, but temporary covered of wounds after debridement, cleared residual microorganism and stimulated granulation tissue growth also have many problems. All these take the challenge for the treatment of severe wound.Vacuum sealing drainage (VSD), which was invented and used by doctor Fleischmann for open injury treatment in1992and has now been widely applied in open wound care and led to good outcomes. Especially in large range of skin soft tissue defect can’t transfer flap to cover wound at the first time. The studies reported VSD can promote blood circulation, increase blood supply, stimulate growth of granulation and at the same time restrain bacteria breeding. VSD, however, can also lead to problems like drainage hole plugging, increasing wounds effusion, infection aggravation, etc. Once severe infection appears the VSD device has to be removed or replaced promptly, increasing pain, hospital stay and cost of the patient. The improved VSD is now quipped with its own flush piping through which injected normal saline or gentamicin solution can play a role in diluting secretions, reducing drainage hole plugging to a certain extent. Physiological saline flushing has no bactericidal effect. Although gentamicin solution flushing has a bactericidal effect, the effect is limited in local use and local use of antibiotics likely produces bacterial resistance.Since ozone or ozone water has a strong oxidizing effect, killing bacteria nonspecifically and efficiently, it has been widely used in treatment of many diseases, such as oral inflammation, skin infections, diabetes foot. Ozone water, as an efficient strong antioxidant, can not only sterilize wounds fast but also promote wound healing. It is important that ozone water does not have the problem of bacterial resistance that almost all antibiotics do.The reason of wound infection is pathogenic microorganism existed. According to the wound secretion bacterial culture results in our department and literature summary in recently years the common bacteria in infected wounds is staphylococcus aureus, acinetobacter baumannii, stenotrophomonas maltophilia, candida albicans, MRSA, colon bacillus, pseudomonas aeruginosa and the most common is pseudomonas aeruginosa. There was lack of uniform sterilizing rate of ozone water report about these bacteria under the condition of in vitro. So design ozone water sterilization experiment in vitro and preliminary understand the ozone water concentration selection at the same time provide reference for VSD combined ozone water treatment of infected wounds animal experiments.Another we hypothesized that a combination of the advantages of both VSD and ozone water may produce better results in infected wound care. Infected wounds may be sterilized more effectively and recovered faster by means of ozone water flushing at a certain concentration through VSD flush piping. Therefore, we designed an animal model of wounds with pseudomonas aeruginosa infection to verify our hypothesis.This research mainly divides two parts. The first part is the sterilization effect of different concentration of ozone water to infected wound’s common bacteria and the second part is the effect and related mechanism of vacuum sealing drainage (VSD) combined with ozone water flushing on infected wounds.First part:A sterilization experiment of different concentration of ozone water to infected wound’s common bacteria.Purpose:Study the sterilization effect of different concentration of ozone water to infected wound’s common bacteria.Method:Different concentration of ozone water (1mg/L,5mg/L and10mg/L) was produced and the normal saline was negative control. An antiseptic experiment about staphylococcus aureus, acinetobacter baumannii, stenotrophomonas maltophilia, candida albicans, MRSA, colon bacillus, pseudomonas aeruginosa was conducted and sterilizing rate of different concentration ozone water was calculated. Result:The mean sterilizing rate of1mg/L ozone water can come up to95.5%in all bacterium of this experiment. The mean sterilizing rate of5mg/L is larger than99.9%for the staphylococcus aureus, acinetobacter baumannii, stenotrophomonas maltophilia, and candida albicans and for the pseudomonas aeruginosa, MRSA, colon bacillus is100%.The mean sterilizing rate of10mg/L ozone water is100%for all the bacteria of this experiment.Conclusion:5mg/L or higher concentration of ozone water can kill infected wound’s common bacteria effectively in vitro.Second part:An animal experimental study on vacuum sealing drainage combined with ozone wate in care of infected woundsPurpose:The effect and related mechanism of vacuum sealing drainage (VSD) combined with ozone water flushing on infected wounds.Method:Animal models of pseudomonas aeruginosa infection were established in40Wistar rats before they were randomly divided into five even groups according to different treatments. Groups A and B were treated with VSD plus5and10mg/L ozone water flushing respectively, group C with VSD plus gentamycin solution flushing, group D with VSD plus normal saline flushing and group E with routine dressing without VSD. The back of the animals was shaved before depilation with6%sodium sulphide24h before the experiment. Fasting and water deprivation were conducted8h before the experiment. When the experiment started, the back of the animals was disinfected before covered with sterile towels. A skin wound (3cm x2cm) involving the muscle layer was created on the central back of the animals. Conventional oppression was used for hemostasis before pseudomonas aeruginosa suspension was daubed over the wound followed by conventional dressing. Immediate debridement was performed in all the40Wistar rats48h after infection when animal models of infected wound were established successfully and the VSD was applied and absence of leakage was secured in all the4flushing groups. Flushing was conducted once every12hours and routine dressing once daily for five days after operation. The WBC, tumor necrosis factor-alpha (TNF-a) and epidermal growth factor (EGF) were detected in every group at the time of modeling,48hours after modeling and five days post-treatment. HE staining of local tissues was conducted to observe inflammatory reaction in every group five days post-treatment.Statistical method:Software SPSS13.0(Chicago, Illinois) was used for statistics. Measurements were expressed as mean±standard deviation (x±s). Comparisons of WBC, TNF-a and EGF immediately after anesthesia,48h after modeling and5days after management were conducted between the five groups using Repeated Measures of General Linear Model. Comparisons of WBC, TNF-a and EGF5days after management were conducted between the five groups using One-Way ANOVA. LSD method was used for comparison between two groups when there was a statistically significant difference (P<0.05).Result:1. The appearance of infected wound after established successfully and5days after management in the5groups.40animal models of infected wound were established successfully and no animals died. Massive green secretion and local redness and swelling appeared on the back of the animals48h after infection. Comparison with other groups, VSD plus ozone water, especially VSD plus10mg/L ozone water, showed a better appearance of wounds5days after management.2. Comparisons of WBC at different time points in the5groups.There were statistically significant differences regarding WBC between immediately after anesthesia,48h after infection and5days after management in all 5groups (P<0.05). The WBC raised48h after infection and reduced significantly5days after management in all the5groups. The WBC5days after management was significantly lower in groups A, B and C than in groups D and E, and significantly lower as well in groups A and B than in group C (P<0.05), but the difference between groups A and B had no statistical significance (P>0.05).3. Comparisons of TNF-a and EGF at different time points in the5groups.There were statistically significant differences regarding TNF-a between immediately after aneasthesia,48h after infection and5days after management in all5groups (P<0.05). The TNF-a raised48h after infection and reduced significantly5days after management in all the5groups. It was significantly lower in groups A, B and C than in groups D and E, significantly lower in groups A and B than in group C, and significantly lower as well in group B than in group A (P<0.05), being the lowest in group B.There were statistically significant differences about EGF at immediately after aneasthesia,48h after infection and5days after management in all5groups (P<0.05). The EGF raised48h after infection and increased significantly5days after management in all the5groups. The EGF5days after management showed a tendency opposite to that of TNF-a. It was significantly higher in groups A, B and C than in groups D and E, significantly higher in groups A and B than in group C, and significantly higher as well in group B than in group A (P<0.05), being the highest in group B.4. Optical microscopy with HE staining.HE staining observation5days after management showed infiltration of partial inflammatory reaction cells in group A, less infiltration of inflammatory reaction cells in group B, obviously greater infiltration of inflammatory reaction cells in group C and massive infiltration of inflammatory reaction cells in groups D and E. Conclusion:compared with routine dressing and VSD combined gentamycin solution or normal saline flushing, VSD combined ozone water flushing have improved effects on promoting the healing of open wounds with pseudomonas aeruginosa infection and the mechanism may be associated with increasing the EGF, restraining TNF-α expression.