50岁以上正常人左室舒张期彩色多普勒血流频谱参数变化的研究

目的探讨５０岁以上正常人左室舒张期脉冲多普勒频谱的参数变化情况。方法选择一年半时间内受检的所有５０岁以上正常人４７５例，按每１０岁为一组分４组进行分析。受检者取左侧卧位，常规显示心尖四腔心切面，取样容积置于二尖瓣尖，使声束与二尖瓣血流方向夹角＜１５°，以连续三个心动周期的平均值分别测量Ｅ峰、Ａ峰、Ｅ／Ａ及Ｅ峰减速时间并统计。结果发现Ｅ峰高于正常值低限的例数、平均Ｅ峰血流速度以及Ｅ／Ａ均随着年龄的增加而下降，Ｅ峰减速时间则随着增龄而增加。结论左室舒张期血流频谱的所有参数与年龄有显著的相关性，明显随着增龄而变化，并且有其规律性。     

主动脉内球囊反搏在小儿中的应用

主动脉内球囊反搏(intraaortic balloon pump，IABP)已广泛应用于成年人心源性休克和围手术期低心排血量综合征的治疗，并取得良好的治疗效果，但在小儿中的应用仍较局限。现就有关IABP在小儿中的应用进行综述，着重分析IABP的适应证和影响在小儿中应用的技术困难和其他因素，介绍小儿IABP应用的技术要点，可能的并发症和治疗效果。在无体外膜式氧合器(ECMO)和左心辅助设备的情况下，小儿心脏直视手术后如不能脱离体外循环机或发生严重低心排血量综合征等，应用IABP治疗可收到较好的效果。     

Effects of Right Ventricular Failure on Renal Function During Pneumatic Left Ventricular Assist

Abstract: In an experimental dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist     

Use of a Paracorporeal Pneumatic Ventricular Assist Device for Postoperative Cardiogenic Shock in Two Children with Complex Cardiac Lesions

Pneumatic ventricular assist device (VAD) was utilized for cardiogenic shock after intracardiac operation in two children with complex cardiac anomalies based with single ventricle. In the first case (a 10-year-old), after a modified Fontan operation, VAD was placed between the functional left atrium and ascending aorta, serving as a "artificial single ventricle" with neither pumping chamber nor artificial support in the right side of the heart. The systemic circulation was maintained by keeping relatively high central venous pressure. In another child (a 3-year-old) who underwent repair of incompetent atrioventricular valve leaving intracardiac lesions, VAD was placed between the common atrium and ascending aorta, serving as a pump for both pulmonary and systemic circulation with regulation of pulmonary blood flow through an aortopulmonary Gore-Tex shunt. The circulatory assist with VAD was utilized for 5 and 6 days, respectively. Although weaning from the device was not feasible in both patients because of the pulmonary dysfunction, these experience showed the possible use of VAD for cardiogenic shock after surgery in patients with complex cardiac anomalies.     

头颈部肿瘤射野摆位误差的差异性研究

目的：研究采用电子射野系统评价头颈部肿瘤患者摆位误差时的观察者间变异和观察者自身变异。方法：两队研究小组，分别由四名医师和四名技师组成，两组分别对6名头颈部肿瘤的患者，采用电子射野影像仪（electronic portal imaging device，EPID）拍摄验证片（electronic portal images，EPIs），在EPIs上勾画骨性标志，以放疗计划生成的数字重建图像（digitally reconstructed radiographs，DRRs）做为参考图像，定量分析不同观察研究人员之间和研究人员自身采用EPID确定头颈部肿瘤患者的射野摆位误差（field placement errors，FPEs）的差异性。结果：在前／后位射野图像上．不同医师之间、医师自身及技师自身对摆位误差的判断无明显差异，但在技师之间出现了明显的自身差异性．医师组和技师组在前／后射野图像上的均方根（root-mean—square，RMS）分别为2．52±0．46和3．43±0．43，两者具有明显差异；在侧位野图像上，医师自身对摆位误差的判断有较好的稳定性，但部分不同医师之间在腹背、头足方向上部分患者中出现差异，而不同的技师之间存在明显差异性，医师组和技师组在侧位射野图像上的RMS分别为2．72±0．16和2．62±0．22．两者无明显差异。结论：医师和技师组在采用电子射野系统对头颈部摆位误差进行判断时存在人员之间的误差，应对所有人员进行统一训练才能减少射野摆位误差，从而提高IMRT治疗效果。     

双凤尾钢板植骨内固定治疗胸腰椎爆裂骨折的生物力学测试

目的 对双凤尾钢板治疗胸腰椎爆裂骨折进行生物力学评价和临床应用观察。方法 取成年男性尸体脊柱标本(T12-L2),制成8具L1椎体爆裂骨折模型。按实际手术方法放置双凤尾钢板。对试件分别进行轴向和弯曲扭转加载测试。临床观察应用双凤尾钢板治疗胸腰椎爆裂骨折的效果。结果 压缩实验和弯曲扭转实验中,各点应变值与载荷均呈线性关系。当轴向载荷达到600N或扭矩达到600N·cm时,这种线性关系未改变。弯扭矩与模型两端之间相对扭转角的增加呈线性关系。弯扭矩达到600N·cm时,扭转角只有6.26°。临床观察表明双凤尾钢板固定可靠。结论 双凤尾钢板固定具有良好的稳定性,表现出高弹性,符合生物学固定的原则。值得临床推广应用。     

Electrical analogy of diastolic pressure difference between left atrium and ventricle

We proposed a mathematical model to describe the early filling process of the left ventricle and applied the model toin vivo experiments. The solution of a second-order differential equation indicated that the pressure difference between the left atrium and ventricle during ventricular filling (PD) could be explained by a transient response, i.e. decremental oscillation, in an LCR circuit. Thereafter, we analysed the sequence of PD during vagal stimulation with two catheter-tip manometers in 12 anaesthetised dogs and evaluated changes in the parameters of the system under various haemodynamic conditions. The values of ω_n and ξ were quite stable among beats within an episode of vagal stimulation, between episodes and even among dogs, despite the changes in haemodynamic variables. Pericardiotomy and partial discommunication of the mitral valve with the left ventricular free wall by cutting the mitral chordal tendons decreased ω_n and increased ζ, mainly because of the increase in C_LV. Occlusion of the coronary vascular beds with large numbers of microspheres increased ω_n and decreased ζ, mainly because of the decrease in C_LV. Mitral obstruction with an inflated balloon (increase in R) abolished the oscillatory changes and produced and exponential decay sequence of PD. In conclusion, both the logical and experimental approaches indicated that the sequence of PD could be considered as decremental oscillation in the LCR circuit and the parameters ω_n and ξ could be good indices of the diastolic property of the left ventricle     

The fourth-generation centrifugal blood pump

 The NEDO Gyro permanently implantable (PI) centrifugal blood pump has been developed as a simple, durable, centrifugal blood pump without a complex magnetic suspension system. In vitro studies were performed using a Gyro PI pump with the transparent pump housing in a mock circuit. These studies revealed that the impeller transfers to a floating or a top contact condition, which was dependent on the revolutions per minute (RPM). This pump can be easily converted from a left ventricular assist device (LVAD) to a right ventricular assist device (RVAD) by simply adding a spacer between the pump and the actuator. In order to optimize the impeller suspension for the LVAD and RVAD, spacers of the proper thickness are inserted between both of the pumps and the actuators to regulate the magnetic force. Two Gyro PI pumps were implanted in a bovine model in a 3-month biventricular assist device (BVAD) animal study. This experiment was electively terminated 90 days after implantation. All of the parameters, including pump flow rate, power consumption, and plasma free hemoglobin, were in acceptable ranges. No thrombus formation was observed in either pump. Antithrombogenesis and effectiveness were demonstrated in this animal study. The NEDO Gyro PI pump is ready to move on to the 3-month preclinical system evaluation. Received: February 28, 2002 / Accepted: May 30, 2002 Acknowledgment The New Energy and Industrial Technology Development Organization (NEDO) under the Ministry of Economy, Trade and Industry of Japan financially supported this project. Correspondence to:S. Ichikawa     

Pressure-flow relationships of the canine iliac periphery and systemic hemodynamics: Effects of sodiumnitroprusside and adenosine

It has been reported that sodiumnitroprusside (SNP) decreases mean systemic pressure and simultaneously increases pressure pulse amplification towards the iliac periphery (Kenner and van Zwieten 1982). This unexpected finding was suggested to be due to a decrease in iliac peripheral resistance but an increase in iliac differential resistance. In order to investigate this apparent contradiction, the iliac periphery was hemodynamically isolated from the rest of the circulation and perfused with the dog's own blood by means of a pump. Perfusion pressure (P) and flow (F), femoral venous pressure (P_v), systemic pressure (P_s) and cardiac output (CO) were measured. Steady state pressure-flow relations of the isolated bed were obtained during control and during various i.v. infusion rates of SNP and adenosine (ADS) and were found to be straight (meanr=0.99). Their slope (P/F) was defined as differential resistance (R_d). Peripheral resistance (R_p) of the iliac bed was defined as R_p=(P-P_v)/F, calculated at the flow value where perfusion pressure equalled the prevailing systemic pressure. Total peripheral resistance (TPR) was defined as TPR=P_s/CO. The changes of R_d, R_p, P_s, CO and TPR with respect to control show that during low SNP infusion rates R_d and R_p were both increased while TPR was decreased. During all infusion rates of SNP CO did not change while P_s decreased. During low infusion rates of adenosine CO increased while P_s, R_d and R_p did not change and TPR decreased. During high infusion rates of ADS CO decreased again, R_d, R_p and P_s decreased, and TPR remained constant but at a decreased level.It is concluded that: (1) the suggestion of Kenner and van Zwieten is not supported, since SNP (as well as ADS) affects iliac peripheral and iliac differential resistance in a similar way; (2) SNP (as well as ADS) affects iliac peripheral resistance and total peripheral resistance in a differentiated way, and even in an opposite way during low infusion rates of SNP; (3) it is this opposite effect that explains the paradoxical observations of Kenner and van Zwieten; (4) for comparable reductions of TPR, CO is better maintained during infusion of SNP, while P_s is better maintained during infusion of ADS.     

Orthofix-微型外固定器治疗Bennett骨折31例

目的分析应用Orthofix-微型器治疗第一掌骨基底部Bennett骨折的临床疗效。方法收集2009年1月~2013年1月我院31例采用Orthofix-微型器治疗的第一掌骨基底部Bennett骨折患者。记录患者年龄、性别等基线资料,以及术后上肢臂、肩、手功能调查量表(Disabilities of the arm,shoulder and hand,DASH)评分,随访终末期采用指总关节活动度(Total action movement,TAM)评分。结果随访6~24个月,平均14.4月,手术时间为18~40分钟,平均29.1分钟,术中出血量10~30m L,平均14.5m L。术后3月、术后6月及终末期DASH评分之间比较,差异均有统计学意义(0.05)。随访终末期,其中26例解剖复位,5例骨折对线良好,TAM评分优22例,良7例,差2例。随访期间未发生桡神经浅支损伤、钉道感染等并发症。结论 Orthofix-微型外固定器治疗Bennett骨折操作简单、疗效满意。