RESUMO
Objective To compare the effects between the dual-cycle intensive training mode (DCITM) of "teaching-in vitro-in vivo-summary-in vitro-in vivo-assessment" and the single-cycle basic training mode (BTM) of "teaching-in vitro-tn vivo-assessment" on training graduate students majoring in cardiovascular surgery.Methods Eight graduate students majoring in cardiovascular surgery received the basic training of coronary artery bypass vascular anastomosis under the mode of BTM or DCITM.Then the training effects were evaluated by scoring of experts.Besides,SPSS 17.0 statistical software was used to analyze the evaluation results.Results Compared with students who received BTM,the postgraduates trained by DCITM became more skilled in vascular anastomosis.In vitro,the average number of anastomosis completed by trainee increased significantly [(2.0 ± 1.0) vs.(5.0 ± 1.5),P＜0.05] over a specified period of time,the vascular leakage rate was significantly reduced [(92 ± 5)％ vs.(30 ± 2)％,P＜0.05],and the average time per anastomosis was significantly shorter [in vitro:(20.1 ± 2.5) min vs.(12.6 ± 3.3) min,P＜0.05].There was also a statistically significant difference in the average time of each anastomosis in miniature pigs with coronary vascular anastomosis [in vivo:(30 ± 2) min vs.(21 ± 3) min,P＜0.05].Conclusion Taken into together,DCITM is a highly efficient mode for promoting the quality of cardiovascular-surgery-teaching and enhancing the effectiveness of training in clinical surgical skills.
RESUMO
The tip structure is one of the key factors to determine the performance of left ventricular assist device (LVAD) inflow cannulas. The tip structure influences the thrombosis, hemolysis in cannula and left ventricle and suction leading to obstruction in ventricle. We designed four kinds of inflow cannulas that had different tips and built the numerical models of the four historical used inflow cannulas inserted into the apex of left ventricle. We computed the hemodynamic characteristics of inflow cannulas insertion by Fluent software. We researched the backflow, turbulent flow and pressure distribution of the four inflow cannulas. The results showed that the trumpet tipped inflow cannula had smooth flow velocity distribution without backflow or low velocity flow. The trumpet tipped inflow cannula had the best blood compatibility characteristics. The trumpet structure could prevent obstruction. The caged tipped cannula had serious turbulent flow which could possibly cause thrombosis and the low pressure near left ventricle wall and easily lead to ventricle collapse. The trumpet tipped inflow cannula has the best blood compatibility and is difficult to be obstructed. The trumpet tipped inflow cannula is fit to long-term use LVAD.