外伤性纵隔气肿对犬心肺功能影响

采用成年杂种犬１２条（１条人工胸膜粘连后），前上纵隔插管，缓慢注气，观察纵隔气肿前后的血流动力学和血气变化。实验观察到纵隔气肿使上、下腔静脉压升高，回心血量减少，心排量下降。纵隔气肿不仅影响体循环，而且影响肺循环，压迫肺静脉，致使肺淤血、水肿。动脉血氧分压和血氧饱和度亦下降，肺内分流增加。实验证明，胸膜粘连犬颈部纵隔切开引流后，其张力得到缓解，血气和血流动力学得到改善。     

坡度对移居海拔3700m高原人体生理适宜负重量的影响

在海拔３７００ｍ高原上测量了１２名男性移居青年以４．０ｋｍ／ｈ速度，在不同坡度（０．５、１０和１５％）和不同负重量（体重的１、１４、２１、２８、３５和４２％）下模拟行走时的ＶＥ、ＨＲ和Ｅ的改变，并根据上述指标随负重增加而出现的非线性增加（拐点）分析了不同坡度条件下行走时的适宜负重，进而观察了坡度对适宜负重的影响。结果表明，适宜负重随坡度的增加而明显降低，关系式为ｙ（适宜负重ｋｇ）＝２０．５１０－１．３５１×（坡度％），相关系数为ｒ＝－０．９６５（Ｐ＜０．０１）．根据上式计算可得，坡度每增加３％，适宜负重降低约２０％（４．０ｋｇ）。该量变关系对估计在其它海拔高度上坡度与适宜负重下降值也有参考意义。     

青年人在高原适宜负重的实验研究

探讨不同海拔高度和不同步速条件下的适宜负重，对于确定高原作业人员合理负重有指导意义。本工作通过高原模拟负重步行试验（跑台）提出适宜负重。在海拔３７００ｍ，步行速度分为４．０、４．５和５．０ｋｍ／ｈ；负重分别为体重的０、１４％、２１％、２８％、３５％和４２％。在海拔４３００ｍ，步行速度分别为３．０、３．５和４．０ｋｍ／ｈ；负重分别为体重的Ｏ、１４％、２１％、２８％、３５％。在海拔５２００ｍ，步行速度分别为２．０、２．５和３．０ｋｍ／ｈ；负重分别为体重的０、７％、１４％、２１％、２８％和３５％。在每个海拔高度上选择移居半年以上的青年学生１２人作为受试对象。每人参加不同速度与不同负重步行试验。根据很累感发生率、ＶＥ、ＨＲ、恢复ＨＲ和Ｅ的改变确定适宜负重。结果表明，在海拔３７００ｍ，速度为４．０、４．５和５．０ｋｍ／ｈ时的适宜负重分别为２０．８、１７．４和１４．１ｋｇ。在海拔４３００ｍ，速度为３．０、３．５和４．０ｋｍ／ｈ时的适宜负重分别为１８．４、１４．３和１０．２ｋｇ。在海拔５２００ｍ，速度为２．０、２．５和３．０ｋｍ／ｈ时的适宜负重分别１７．３、１４．２和１１．４ｋｇ。     

异丙酚诱异对心瓣膜手术病人血流动力学的影响

目的和方法：采用Ｓｗａｎ－Ｇａｎｚ导管及热稀释法检测心搏量技术,观测心瓣膜手术病人异丙酚（１．５ｍｇ／ｋｇ）诱导时的血流动力学（血动学）变化。结果：两组病人麻醉前血动学紊乱主要表现为右心后负荷及作功增加;给予异丙酚１．５ｍｇ／ｋｇ后２ｍｉｎ,ＨＲ、ＣＩ、ＭＰＡＰ、ＭＡＰ、ＭＣＷＰ、ＬＶＷＩ、ＲＶＷＩ较麻醉前明显降低,在无气管插管操作刺激的Ａ组中可一直持续,并超近１０ｍｉｎ;Ｂ组病人麻醉后３ｍｉｎ行     

Bioprosthetic heart valves--replacing order with chaos: electron microscopic study

Rheumatic heart disease is a significant clinical entity in young children, especially in the developing world. One of the major long-term effects of ill managed rheumatic fever is irreversible damage to the cardiac valve leaflets, primarily on the left side. With the limited success of currently available mechanical and bioprosthetic valves, there is an urgent need for new directions in bioprosthetic valves, both in material, including source, degree of fixation, surface, bulk modifications, etc., and design. In the present paper, new proposals in the material selection and fabrication of bioprosthetic valves are proposed based on electron microscopic studies of natural valve leaflets and the pericardial surface. Current approaches for bioprosthetic valve fabrications include the wide use of the pericardium as a leaflet material. The present study indicates a need for nondestructive surface examination of pericardial sheets for the elimination of areas of surface voids resulting from gross fiber disorientation. Also, there seems to be a need for incorporation of an in situ fiber renewal mechanism in bioprosthetic leaflets to emulate the natural valve more closely. Apparently natural leaflets have built-in fiber renewal mechanism(s).     

Nitric oxide inhalation as a chemical assist for circulation in patients after cardiovascular surgery

The objective of this study was to investigate whether nitric oxide (NO) inhalation might be an alternative strategy as a chemical assist for the circulation in patients showing a deterioration in oxygen delivery. Twelve adult patients whose oxygen delivery indices (DO2I) were less than 400 ml/min/m2 after cardiovascular surgery were included in this study. NO was administered via a premixing system or a side stream system at doses between 1 and 10 (5.1+/-2.4) ppm. Data obtained before and during a 120 min NO inhalation were compared using the paired Student's t-test. The increase in PaO2/FiO2 resulting from NO inhalation was significant (from 162 to 251 mm Hg). DO2I increased significantly from 326 to 417 ml/min/m2 concomitantly with significant increases in both arterial oxygen content (CaO2) and cardiac index (CI) (from 14.1 to 15.4 vol% and from 2.31 to 2.71 L/min/m2 , respectively). The increase in SvO2 during NO inhalation was significant (from 55.2 to 62.6%). Among the other hemodynamic parameters, both total pulmonary resistance and systolic pulmonary arterial pressure (SPAP) showed significant decreases during NO inhalation, but right atrial pressure did not change significantly. There was a close relationship between the baseline SPAP level (bSPAP) and the decrease in SPAP during NO inhalation (dSPAP) (r = -0.88). However, negative correlations were observed between bSPAP and percentage increase in CI (%CI) (r = -0.61) and between bSPAP and percentage increase in DO2I (%DO2I) (r = -0.48). Moreover, positive relationships were observed between dSPAP and %CI (r = 0.62) and between dSPAP and %DO2I (r = 0.45). Hemoglobin (Hb) increased significantly from 11.0 to 11.4 g/dl. There were no significant changes in Fio2, pH, PacO2, or base excess (BE) during NO inhalation. The level of methemoglobin measured during the study period remained within the normal range (0.86+/-0.23%). In conclusion, NO inhalation could be an efficient and alternative assist for the circulation in patients whose oxygen delivery deteriorates after cardiovascular surgery.     

Unreported cardiac arrhythmias in aluminium worker

Aluminium (Al) is the third most prevalent element, representing approximately 8% of total mineral components in the earth's crust (1). Chronic exposure to Al is mainly encountered at particular work places, for example, in foundries or in the Al powder industry, as an occupational exposure. In case of occupational Al exposure, inhalation is the main route of uptake. Chronic exposure to Al is associated with skeletal, neurological, hematological and lung changes. Studies regarding the Al powder industry showed that long-term inhalative exposure to Al can induce pulmonary fibrosis (2). Although there is only one report about ventricular tachycardia as a cardiac manifestation in occupationally exposed persons (3), in this report, we presented a case that had Mobitz type I second-degree atrioventricular block and nonsustained ventricular tachycardia. To our knowledge, this is the first report in chronic poisoning.     

Cardiac laceration without any external chest injury in an otherwise healthy myocardium – A case series

The heart is relatively well protected within the thoracic cavity from all the sides. Thus it is rather uncommon to find a cardiac laceration in cases of blunt trauma to the chest and that too when there is no evident injury to the chest wall. Several cases with history of death following blunt trauma were autopsied by us in recent months. Out of them, 3 cases that did not exhibit any external chest injury revealed hemopericardium following rupture of a cardiac chamber. The volume and suddenness of appearance of the hemopericardium were sufficient to cause tamponade. These case reports underline the importance of a systematic and complete autopsy in all cases of blunt trauma deaths even though they may be having no external injury. They also highlight that myocardial injury must be ruled out in every living patient presenting with blunt chest trauma even in the absence of an external sign.     

CT imaging in congenital heart disease: An approach to imaging and interpreting complex lesions after surgical intervention for tetralogy of Fallot,transposition of the great arteries,and single ventricle heart disease

Echocardiography and cardiac magnetic resonance imaging are the most commonly performed diagnostic studies in patients with congenital heart disease. A small percentage of patients with congenital heart disease will be referred to cardiac CT subsequent to echocardiography when magnetic resonance imaging is insufficient, contraindicated, or considered high risk. The most common complex lesions referred for CT at our institution are tetralogy of Fallot, transposition complexes, and single ventricle heart disease. This review discusses the most common surgical procedures performed in these patients and the technical considerations for optimal image acquisition on the basis of the prior procedure and the individual patient history. Cardiac CT can provide the functional and anatomic information required for decision making in complex congenital heart disease. Image interpretation is aided by knowledge of the common approaches to operative repair and the residual hemodynamic abnormalities. Acquisition and interpretation that is both individualized to the patient's underlying disease and the specific clinical question is likely to maintain diagnostic accuracy while decreasing the potential risk of cardiac CT.     

胸腰椎运动段极限载荷值与对应的应力值测定及其临床意义

目的探讨脊柱的力学特性及损伤机制。方法采用１０具新鲜成年尸体胸腰椎（Ｔ１２，Ｌ１）建立运动段，测定胸腰椎脊柱在压缩及拉伸载荷下的极限载荷值与对应的应力值。结果测定压缩极限载荷值为４６０±５０ｋｇ，拉伸极限载荷值为３５０±３５ｋｇ及各组织相对应的应力值。结论对航空领域中各种致伤因素下飞行员脊柱损伤的研究具有一定的参考价值