Study On The Correlation Between Muscle Bioimpedance And Its Vitality

Objective: With the rapid development of modern construction andtransportation, the incidence of high-energy injury is increasing constantly,and some severe soft tissue injury (degloving injury, vascular injury etc.) cancause skin, muscle and other tissue necrosis,even the amputation. Therefore, acorrect estimate of tissue vitality and timely treatment of impaired tissue, isthe guarantee of clinical treatment and therapeutic effect. At present,thededuction of muscle necrosis includes some following methods,electrophysiological method, pathological method and noninvasive method,such as visual inspection, percutaneous oxygen partial pressure method. Themethod of pathology tests is very expensive and the test results only reflect thesample's changes. The visual inspection is rough and not precise, ofteneffected by examinee experience. Therefore, in order to explore a simple,objective and accurate judgement of biological tissue vitality, we designed thisexperiment. After skeletal muscle injury or ischemia,muscle will occurcomplex biological electrochemical reaction and these reactions will bereflected through muscle fiber structure,so some muscle electrical parameterscan reflect the characteristics of muscle tissue. The impedance of musclecaused by vascular injury(blood supply blocking) was measured by applying aBio-impedance measurement. In this experiment, we try to analysis thecorrelation between the change of impedance and ischemia time, and explorethe biological impedance changes in muscle vitality and the feasibility of themethod, looking for an early, simple and relatively accurate method of musclevitality.we hope this experiment result will apply a new rationale or methodfor examination of tissue vitality, clinical debridement and some related study.Methods:1Experimental objects14New Zealand rabbit, male,age6months, weight2.0-2.5Kg. Provide by the animal experiment center of Hebei MedicalUniversity.2Animal experimental model All the experimental rabbits were used3%pentobarbital sodium through around ear vein for anesthesia,injection dose30mg/kg. After anesthesia successfully, dissect and free femoral artery onboth sides of the thigh root,noninvasive artery clamp block the femoral artery,record the hemostasis time and interval,to make the animal experimentalmodel(Fig.3).3Experimental method14healthy and adult rabbits were randomly assignedby random grouping principle,each group of2. Start time at0hour,in eachgroup,dissect and free femoral artery on both sides of the thigh root,noninvasive artery clamp block the femoral artery at the same interval and theblocking time increase by every4hours,the longest blocking time for24hours. Measure and record impedance value according to each group wheninput a signal frequency(100KHz)current along the muscle fiber direction, atthe same time,take one ipsilateral (left) gastrocnemius muscle at the samelocation and the same size of muscle tissue for pathology form each group.Muscular impedance of each group was measured by four-electrode method(Fig.2)and when measuring and collecting the date try to controltemperature and humidity conditions properly.4Date and pathology analysis The impedance data of different ischemic timewas calculated by SPSS17.0. Observe muscle impedance value trend atdifferent ischemia time, to guess the correlation between musclebioimpedance and tissue vitality and explore a new method for the speculationof tissue vitality based on tissue impedance.Results: As the ischemia time of gastrocnemius muscle increased,bioimpedance value is also present an increasing trend. Different ischemictime of impedance mean are0hour：51.32,4hours：54.53,8hours：63.88,12hours：71.06,16hours：86.27,20hours：99.73,24hours：121.01.The pathologic changes of different ischemia time are：in the earlyischemia stage, the musculature was not changed apparently both in electron microscope and optical microscope. With the extension of ischemia time, thechange of musculature structure was appeared gradually. Optical microscope:the number of swelling muscle bunch and dissolved cells were increasedgradually, but the proportions were very few. Electronic microscope: thedegree of mitochondria swelling, glycogen reduce and sarcomere disorderpresented a kind of increasing trend changes. At the early state, the change inelectrical properties of skeletal muscle tissue was earlier than the organicchange after ischemia. The results showed that the impedance of differentischemic time can reflects the corresponding pathological changes. Accordingto the correlation between impedance and ischemia time, it is feasible todeduce the vitality of muscle through the change of its impedance.Conclusion:(1) In24hours, after skeletal muscle ischemia caused byvascular injury, the impedance value shows an increasing trend,that is, as themuscle vitality reduces its impedance value increases gradually.(2) Thechange in electrical properties of skeletal muscle tissue was earlier than theorganic change after ischemia.(3)According to the correlation betweenimpedance and ischemia time, it is feasible to deduce the vitality of musclethrough the change of its impedance. Consequently, bioimpedance technologycan provide a new theory and method for the early, non-invasive and simplededuction of muscle vitality.