ABSTRACT
Objective To explore the viscoelasticity of relaxed myocardium in vivo through indentation method with an intervention ultrasound indentation system (IUIS). Methods Old myocardial infarction (OMI) models of canine were established by ligating left anterior descending branch of coronary artery for 3 months. The indentation creep tests were used respectively in OMI group and shame group (n=8, each) by IUIS in middle and advanced diastole stage in vivo. Test data were processed with three-parameter solid viscoelasticity model, and the viscoelastic parameters, such as instantaneous elastic modulus (E1), relaxation modulus (E∞), creep elastic modulus (E2) and viscous damping coefficient (η) in normal and infarcted myocardium were obtained and compared. Results All the parameters of E1, E∞, E2 and η increased obviously in OMI group than in sham group shown as follows: 27.81±6.74kPa vs. 6.78±2.43kPa; 17.87±3.59kPa vs. 4.52±1.56kPa; 49.54±14.35kPa vs. 16.82±12.37kPa and 1.97±0.78Pa.s vs. 0.66±0.40Pa.s. The differences were statistically significant (P<0.05). Conclusions IUIS is a feasible method to assess the viscoelasticity of relaxed myocardium in vivo. Three-parameter viscoelasticity model can be used to describe creep properties of relaxed myocardium. Both elastic modulus and viscosity resistance have increased in infarcted myocardium.
ABSTRACT
Objective To observe the preventive effect of the new nursing mode on the formation of deep venous thrombosis(DVT)in pregnant women with high risk factors.Methods 186 pregnant women who had high risk factors were selected,by using digital table method they were randomly divided into control group(93 cases)and observation group(93 cases).The control group was treated with routine nursing,the observation group was given the new nursing mode on the basis of routine nursing.The postpartum 2 weeks of lower limb swelling,pain,lower extremity deep vein thrombosis formation of incidence,and the nursing satisfaction were compared between the two groups. Results 2 weeks postpartum,the incidence rates of lower limb pain occurrence,lower extremity deep vein thrombosis in the observation group were 8.6%,2.1%,which in the control group were 20.4%,9.7%,there were statistically significant differences between the two groups(χ2 =4.56,4.82,all P <0.05).The satisfaction of the observation group was 95.6%,which of the control group was 81.7%,the difference between the two groups was statistically sig-nificant(χ2 =5.27,P <0.01).Conclusion The new nursing model used in pregnant women with high risk factors can effectively prevent the occurrence of DVT,reduce the incidence of DVT,improve the satisfaction of nursing.