| Vacuum sealing drainage (VSD) is a new surgical technique, which consists of polyethylene alcohol hydration foam, biological semipermeable membrane, drainage tube and negative pressure source. The foam, served as an agent between wound and drainage tube, fills the wound caused by skin or soft tissue defects, infection and necrosis.VSD foam brings changes of drainage from traditionally punctate or linear one to omni-directional and multi-dimension drainage. Biological semipermeable membrane is used to cover and seal the wound and drainage tube is used to connect the foam and negative pressure source. Therefore, VSD technique can make the wound in a totally-enclosed, continuous or intermittent negative pressure drainage environment.There are many advantages for wound therapy managed by VSD technique, which can facilitate blood circulation, increase the blood supply, alleviate edema around the wound, accelerate the wound healing, inhibit the bacteria breeding and control infection, offer effectively mechanical traction and stimulate the growth of granulation tissue. However, VSD technique also has many disadvantages. Firstly, although the technique has extensive indications, it also has a few contraindications. Secondly, although the technique can inhibit bacteria, its capacity of bacteriostasis is limited. Thirdly, although it provideds airtight environment for the wound, it is sometimes difficult to seal the wound absolutely. Fourthly, although the clinical efficacy is prominent, it has limited capacity. There is a frequent phenomenon in clinical application that some patients managed by VSD technique still have different levels of wound infection. Results of bacteria culture from wound secretion include staphylococcus aureus, escherichia coli, pseudomonas aeruginosa and baumanii et al.. These infected wound is often managed by the irrigation of gentamicin solution currently. However, there are mainly two drawbacks of this method. On the one hand, local antibiotic application may result in bacterial resistance easily and often leads to poor clinical efficacy. Secondly, it seems very difficult for one single antibiotic in the treatment of multiple bacterial infections.In recent years, ozonated water has been more and more widely applied in wound healing and anti-infection. Many studies have proved that ozonated water has an excellent bactericidal effect on bacteria, bacterial spore, virus, fungus and protozoon et al.. The bactericidal effect of ozonated water is prompt, which means instantaneously. Ozonated water has two kinds of oxidizing reaction, including the direct reaction between microbial body and ozonated water as well as indirect reaction between microbial body and-OH decomposed from ozonated water. Ozonated water has a quite rapid sterilization speed as-OH is an oxidant of extremely strong oxidizing. Ozonated water can not only kill bacteria in the wound, but also can accelerate wound healing. Besides, ozonated water can produce oxygen after natural decomposition, which increases the oxygen concentration in local tissue. The increased oxygen concentration can improve the oxygen-deficient environment and accelerate the wound healing effectively.VSD technique has advantages and disadvantages. The limited ability of anti-infection is the bottleneck for its further development. We try to combine the two methods in infected wound therapy, that’s to say, when VSD technique is applied, ozonated water is used to irrigate the wound through drainage tube. If the hypothesis is feasible, great advantages can be identified of the combination easily. The application of VSD technique can increase the blood supply to the wound, alleviate edema around the wound and stimulate the growth of granulation tissue while the application of ozonated water can effectively kill the bacteria of the wound. Besides, the decomposition of ozonated water results in high oxygen concentration in local tissue, which will kill anaerobe effectively. Ozonated water can overcome the defects of VSD technique and expand its indication range. Moreover, synergistic effect can be identified between the two in facilitating wound healing. All the above advantages will bring huge social and economic benefits.Considering that ozonated water has a certain degree of oxidability, the premise of the combination is that VSD material can bear the oxidability of ozonated water and the physical and chemical properties of the material do not change greatly. The aim of this experiment is to evaluate the feasibility of combined application of VSD technique and10μg/ml ozonated water. Two main reasons can account for the selection of10μg/ml ozonated water in the experiment. One reason is that previous studies have reported that10μg/ml ozonated water is able to kill most pathogenic microorganism. The other reason is that high concentration ozonated water may bring oxidative injury to normal tissues. Therefore, the concentration of ozonated water should satisfy the demand of killing pathogenic microorganism as well as not cause injury to normal tissue. If it is feasible to combined VSD technique and ozonated water in material science, further explorations will be performed on safety study in vivo and animal experiment, all of which will pave the way for clinical popularization and application. Our experiment consisted of three parts. Part One included the production of10μg/ml ozonated water, concentration detection of ozonated water at different temporal points and exploration of metabolic rules of ozonated water under certain circumstance. Part Two explored the effect of10μg/ml ozonated water on physical and chemical properties of VSD material. In Part Three, we made a VSD analog device in vitro and used10μg/ml ozonated water to irrigate the analog device. The airtightness of the device was checked after irrigation to prove the feasibility of combined VSD technique and ozonated water.Purpose:The aim of chapter one was to produce10μg/ml ozonated water, detect the concentration of ozonated water at different temporal points using iodometry and draw the metabolic curve of ozonated water to explore its metabolic rule.Materials and methods:1. Production of ozonated water:We poured sterile water for injection into the water storage tank of ozonated water generator (type:Ozonosan Alpha Plus1107). The oxygen valve was opened and10μg/ml ozonated water was produced using ozone bubbling method. Ozonated water was stored in Amber Laboratory Bottle.2. Detection of ozonated water using iodometry:Based on the "the concentration, yield, power consumption measurement and calculation method of ozone generator" in the "Construction of Urban Industry Standard of People’s Republic of China"(CJ/T3028.2-1994). We used alkali burette, conical flask, volumetric flask and measuring cylinder to weigh chemical reagent.20%iodine-potassium iodide,1+5sulfuric acid solution, O.Olmmol/L sodium thiosulfate solution and starch solution were used in the experiment. The chemical equations of the experiment were listed below. ①O3+2KI+H2O—O2+I2+2KOH②I2+2Na2S2O3—2NaI+Na2S4O6Calculation formula:C (03)=2.4×V(Na2S2O3) V:usage amount of Na2S2O3The concentration of ozonated water was detected at0min,15min,30min,60min,90min and120min after ozonated water was produced, respectively. Five repeated experiments were performed for each control point. The results were expressed in mean±standard. Metabolic graph was drawn using the mean concentration of ozonated water at different temporal points.Results:10μg/ml ozonated water was successfully produced. The mean value of initial concentration of ozonated water was (9.94±0.27) mmol/L. After natural metabolism of15min,30min,60min,90min,120min in certain circumstances, the remaining concentration of ozonated water were (7.46±0.16) mmol/L、(5.93±0.13) mmol/L,(4.11±0.56)mmol/L,(1.63±1.12)mmol/L,(1.10±0.03)mmol/L, respectively.Conclusion:10μg/ml ozonated water can be produced using the type Ozonosan Alpha Plus1107ozone generator and the concentration of ozonated water produced by this machine is steady. The characteristic of ozonated water is instable, which can degrade spontaneously. After two hours of natural metabolism, certain concentration is still existed in the ozonated water.Purpose:To explore the effects of10μg/ml ozonated water on physical and chemical properties of VSD foam and membrane.Materials and methods:1.(1) The divided experimental groups was as follows:Control group, eight days’effect by normal saline, eight days’ effect by chlorhexidine, one day’s effect by ozonated water, two days’ effect by ozonated water, four days’effect by ozonated water and eight days’ effect by ozonated water.(2) Experimental intervention:After10μg/ml was produced and kept in Amber Laboratory Bottle (room temperature21℃±℃), VSD material was immersed in the ozonated water for one hour a time, twice a day with a continuous eight days. Physical and chemical properties were tested at the end of1day,2days,4days and8days, respectively. VSD material in normal saline and chlorhexidine groups were intervened with the same method as in the ozonated water group.2. Gross appearance:After intervened by different methods in different groups, we observed the surface structure changes (e.g. appearance, color and luster etc.) of VSD material.3.Microstructure:After VSD foam and membrane were disposed and put in glass slide, we used appropriate microscope magnification to observe the microstructure of VSD material.4. Tension test:After VSD material was put in the clamp of tensile test machine, we modulated VSD material to make the longitudinal axis of the material coincident with the longitudinal axis of the clamp. The initial scale distance for VSD foam and membrane were both20mm and the test velocity for VSD foam and membrane were400mm/min and200mm/min, respectively. The test temperature was25℃and humidity was70%. After the sample was completely ruptured, we recorded the outcomes including the maximum load and the momentary distance at the sample torn.5. Micro Raman spectrum analysis:VSD material was put in Raman spectrometer (type:LabRAM Aramis) after being disposed, we used532.8nm wavelength laser,50×objective lens,1200g/nm optical grating. The exposure time was5seconds for twice and the scan range was400～4000cm-1, with1cm-1resolution. The test temperature was26℃and humidity was61%. After data on VSD foam and membrane before and after intervened by ozonated water were collected, we used Origin Pro8.0software to draw the Raman spectra.6. Statistical analysis:Statistical analysis was performed using SPSS13.0software. Measurement data was expressed in mean±standard deviation. One-way ANOVA was used to compare the means among different groups. F-test was used for homoscedasticity and Bonferroni method was applied for multiple comparisons. Welth method of Pseudo F test was used for heteroscedasticity and Dennett’s T3method was applied for multiple comparisons. T-independent test was applied for the comparison of measurement data between two groups. P values of≤0.05were considered significantly different.Results:After intervened by10μg/ml ozonated water for continuous eight days, no obvious abnormalities of VSD material was observed in gross appearance as well as microstructure. Results of tension test indicated that the maximum load and momentary distance at the sample torn of VSD foam were gradually reduced as the intervened time by ozonated water was increased. The maximum load of VSD foam before and after intervened by10μg/ml ozonated water for eight days were (4.25±0.73)、(2.44±0.19) kgf (P=0.001). The momentary distance at the sample torn of VSD foam before and after intervened by10μg/ml ozonated water for eight days were (92.54±12.83)、(64.44±4.60) mm (P=0.006). However, no significant differences were identified in the maximum load and momentary distance at the sample torn of VSD membrane as the intervened time by ozonated water was increased. The maximum load of VSD membrane before and after intervened by10μg/ml ozonated water for eight days were (0.70±0.06)、(0.74±0.08) kgf (P=0.402). The momentary distance at the sample torn of VSD foam before and after intervened by10μg/ml ozonated water for eight days were (102.85±9.35、(96.02±15.83) mm (P=0.430). Results of Raman spectrum indicated that only a few wave crest intensities of VSD material were observed in the scan range of400～4000cm-1, which implied that no new chemical group were generated.Conclusion:After intervened by10μg/ml for continuous eight days, no significantly physical or chemical property changes were tested except for the decreased tensile properties of VSD foam.Purpose:To make VSD analog device in vitro and investigate the effect of10μg/ml ozonated water on airtightness of VSD analog device in vitro.Materials and methods:We put four VSD foam (5cm×5cm×1cm) on a glass pane (25cm×35cm×0.5cm) and pasted VSD membrane onto the VSD foam. Then, airtightness was checked under negative pressure source. After confirmed examination of fine airtightness of the analog device,10μg/ml ozonated water was prepared and30ml ozonated water was injected for each analog device. After ozonated water effect for one hour a time, twice perday for continuous eight days, airtightness of the device was checked under negative pressure source.Results:VSD analog device was successfully made and no air leakage was checked under negative pressure source. After intervened by10μg/ml for eight days, no air leakage was identified and the airtightness was still fine.Conclusions:No significant effect was identified regarding the effect of10μg/ml ozonated water on airtightness of VSD analog device in vitro. |
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