An Experimental Research On The Relationship Between The Oppression Time Interval And The Formation Of Pressure Ulcers

Objective: By establishing the SD rats pressure ulcer animal models, this paper compares the two different injury situations in SD rats skin and subcutaneous tissues under the naked eyes and pathological aspects by using same oppression time interval method and gradually extending the oppression time interval method so as to differentiate the effects of these two methods in rat skin tissue injury.Methods: Taking healthy male SD rats as experimental animals, after the anesthesia, put them in simple compression devices supinely and, regarding the rat hind limb joints as oppressed points, obtain the pressure A after two hours'sustained pressure. Then, regarding pressure A as experimental pressure, under visual observation and pathological observation, study the rat skin tissues injury situations by differentiating the same oppression time interval method (hereinafter referred to conventional method) and the gradually extending oppression time interval method (hereinafter referred to experimental method).(1) The first stage: Pre-experiment. In this experiment, the pressure of 70 mmHg as the largest value of pressure and four SD rats a group, through pre-experiment we obtain that the biggest pressure to make the limbs of experimental animals red is the Maximum pressure (Pm), and non-redness of all experimental animals is the minimum pressure (P n).(2) The second stage: Access to test pressure A. 48 healthy male SD rats are randomly divided into six groups. The pressure size is respectively divided into by geometric series: 70 mmHg(95 cmH2O), 64mmHg (87cmH2O), 58mmHg (80cmH2O), 53mmHg (72 cmH2O), 48mmHg (65cmH2O , 44mmHg (60cmH2O). The experimental animals'hind limb joints are oppressed two hours to observe compression skin color change (redness is positive result). Then, by K?rbar's calculation, calculate the pressure A that made half animals'compression skin red.(3) Third stage: Compare the two methods that made animal skin color change. After the anesthesia, 104 healthy male SD rats are put in simple compression devices. Then, these rats are randomly divided intoâ‘ Control group (group C, n = 48). Lying supinely in the devices, the rats are oppressed two hours and have two hours relaxed. In accordance with the compression time difference, they are divided into No.1 cycle group (C1 group, n = 8);No.2cycle group (C2 group, n = 8);No.3 cycle group (C3 group, n = 8 ); No.4 cycle group(C4 group, n = 8); No.5 cycle group (C5 group, n = 8); No.6 cycle group (C6 group, n = 8).â‘¡Experimental group (group E, n = 56). Lay supinely in the devices. The compressions way is the gradual extension of the pressure time interval, 0.5 hours oppression and 0.5 hours relax for the first time. Each oppression time and oppression relax will be the extension of time 30 minutes, that is, 1 hour oppression and one hour relax, so as to analogize, until the time is 3.5 hours oppression. Groups are divided by the different ends of extension time: 0.5 hours after the oppression and 0.5 hours relax (E1, n = 8); oppression extended to one hour relaxing one hour (E2 group, n = 8); oppression 1.5 hours extended to relax 1.5 hours (E3 group, n = 8); oppression extended to two hours relaxing two hours (E4 group, n = 8); oppression 2.5 hours extended to relax 2.5 hours (E5 group, n = 8); oppression extended to three hours relax 3 hours (E6 group, n = 8); oppression 3.5 hours extended to relax 3.5 hours (E7 group, n = 8). At the end of the experiment, by comparing the visual observation shape, the color observation and the pathological changes under light microscopy observation, we analyze the compression skin and subcutaneous tissue injury situations, and compare with the control group.Results:1. Each group has no visible skin damages and other serious changes, but compression local skin redness is visible. The redness comparison differences between control group and experimental group are statistically significant (P <0.05). . 2. Under the experimental conditions, the size of the pressure of the skin redness among half of the animals (pressure A) is 55.08 mmHg.3. The comparison differences between control group and experimental group in the aspects of neutrophil infiltration degree, mast cell aggregation, and mast cell deregulation rate are statistically significant (P <0.05). .Conclusion:1. Under these experimental conditions, the oppression method of gradually extending the time interval can reduce tissue injury, which manifests specifically in the visual observation result and the pathology target.2. The neutrophil infiltration degree and mast cell deregulation rate are taken as the important references of evaluating the degree of oppressed tissues injury.3. In the clinical judgment of degree I pressure ulcers, the visual observation results can, to a certain extent, reflect the pathological changes in body tissues.4. Some scholars have put forward after a certain period of time compression pressure on the skin tolerance can be gradually increased, which can be gradually extended to turn over and the time of each stage extended 30 minutes. The results of this study and the clinical practice match. Therefore, the results of this study may in the future provide clinical nursing intervention in the implementation of certain theoretical support.