Experimental Study On Topical Oxygen Therap Combined With Vacuum-assisted Closure Intervention In Ⅲ Period Pressure Ulcer

The experiment on the basis of construction of animal model for Ⅲperiod pressure ulcer in guinea pig, to observed the effect ofvacuum-assisted closure (VAC) in combination with Topical oxygentherapy(TOT) on the treatment of Ⅲ period pressure ulcer in guinea pig,to investigate the action mechanism, To study the best working conditionsfor topical oxygen therap combined vacuum-assisted closur.PartⅠ: Construction of animal model for Ⅲ period pressure ulcerin guinea pigSelected21clean male white guinea pig, According to theischemia-reperfusion principle, Ⅲ period pressure ulcer was induced onguinea pig the left trochanter major exert different pressure(50mmHg、100mmHg、150mmHg、200mmHg、250mmHg and300mmHg) cycle usinga pressure applicator. The skin injury was measured from the naked eye,pathological and behavioral tripartite face. The result showed: Woundcolor and morphological features were similar on each experimental group,but time is inversely proportional to the pressure size. HE staining showed different degrees of histopathological damage characteristics, such as thehierarchy of fuzzy, inflammatory cell infiltration, muscle stripes blur ordisappear, vascular stasis, muscle tissue degeneration, autolysis, goup B<C~D <E~G. Compared with the control group, the experimental groups ofguinea pigs diet quantity, water quantity and quality change had asignificant difference (P<0.01). With the increase in the pressure applied,the appearance of guinea pigs, mental status, gait and temperament hasgradually appeared abnormal.PartⅡ: Topical oxygen therapy combined with vacuum-assistedclosure intervention wound healing of Ⅲ period pressure ulcer in guineapig modelSelected20clean male white guinea pig, construction of animalmodel for Ⅲ period pressure ulcer in the left trochanter major of guineapig, method with the first partⅠ.20wounds were divided randomly intofive groups: Group A were treated with Continuous VAC (-125mmHg) for320min and TOT (5L/min) for160min; Group B were treated with VAC(-125mmHg) for40min and TOT (5L/min) for20min, Alternating8times;Group C were treated with VAC (-125mmHg) for40min after suspensionof20min, Repeat8times; Group D were treated with TOT (5L/min) for20min after suspension of40min, Repeat8times; Group E were treatedwith conventional double saline gauze and sterile porous polyurethanesponge dressing change every other day. Measuring wound area at the given time point (immediately the wounds were created and the1st,3rd,7th,11th day after the treatment), then calculate wound shinkage rate.Tissue specimens, collected from the wound, were embedded with paraffinand studied with HE staining to detect the edema and inflammatory cellinfiltration. Determination of VEGF and MVD mean density in thetissue.The result showed:①The wound shinkage rate: Experimentalgroup (Group A~D) were higher than Control group (P<0.001). Combinedintervention group (Group A~B) were higher than VAC group and TOTgroup (P<0.001). The alternate joint intervention group was higher thanthat of sequential combined intervention group (P<0.001). Nosignificantly differences were found between VAC group and TOT group(P>0.05).11days after the intervention, each wound shinkage rate frombig to small order of Group B>Group A>Group D>Group C>Group E, andGroup B the wound has healed.②VEGF: Group A~D was higher thanGroup C (P<0.001). Group C was higher than Group D~E (P<0.001).There are no significantly differences between Group C and Group D(P>0.05).③MVD: MVD expression of Group A~B was higher thanGroup C~D (P<0.001). There are no significantly differences betweenGroup C and Group D (P>0.05), but were higher than that of controlgroup (P<0.001).PartⅢ: Optimization of working conditions for topical oxygentherap combined with vacuum-assisted closure Selected20clean male white guinea pig, construction of animalmodel for Ⅲ period pressure ulcer in guinea pig, method with the firstpartⅠ. Using of guinea pig model of Ⅲ period pressure ulcer, theuniform design and multiple regression analysis were applied toinvestigate topical oxygen therap combined with vacuum-assisted closureintervention wound of Ⅲ period pressure ulcer healing for intensity ofnegative pressure, oxygen flow, within an hour topical oxygen therapworking time, intervention frequency on daily average of wound shrinkagerate. The result showed: The best working conditions for topical oxygentherap combined vacuum-assisted closure intervention in guinea pig modelof Ⅲ period pressure ulcer was ascertained as follows：intensity ofnegative pressure=-125mmHg, oxygen flow=10L/min, within an hour theTOT working time=50min, intervention frequency=12times/day.Conclusions:1. In the100mmHg pressure, Ⅲ period pressure ulcer was inducedon guinea pig the left trochanter major by Take the ischemia-reperfusionmethod(ischemia2h, reperfusion0.5h),4cycles a day,12cycles in a row(3days), after5days hard callus dissolved, duration of infection. Themodel can be used for long-term observation of the pressure ulcer study.2. Topical oxygen therapy combined with vacuum-assisted closurecan significantly promote healing of Ⅲ period pressure ulcer in guineapig, and it is more effective than VAC group and TOT group. 3. The alternate joint intervention therapy to promote wound healingeffect is superior to sequential combined intervention therapy.4. VAC and TOT monotherapy efficacy of same, and were better thanthe control group.5. VAC and TOT combined intervention therapy can rapidly reducewound inflammation, promote VEGF and MVD expression, increasedwound vascularization degree, promote wound healing of Ⅲ periodpressure ulcer in guinea pig.6. The best working conditions for topical oxygen therap combinedvacuum-assisted closure intervention in guinea pig model of Ⅲ periodpressure ulcer was ascertained as follows： intensity of negativepressure=-125mmHg, oxygen flow=10L/min, within an hour the TOTworking time=50min, intervention frequency=12times/day.