人工心瓣膜患者微栓子信号和凝血活性的相关性研究

目的 :研究人工心瓣膜患者脑动脉微栓子信号 (MES)的数量及相对强度与凝血活性的相关性。方法 :采用双门深经颅多普勒 (TCD)检测人工心瓣膜患者脑动脉MES ,同时检测患者凝血酶原时间国际通用比值 (INR) ,观察MES数量及相对强度与INR的相关性。结果 :MES阳性发现率 83 33% (2 5 30 ) ,MES出现频率 0～ 4 0 4 (中位数 4 0 )个 h ,MES平均相对强度 11～ 38(2 3 6 3±5 13)dB。INR1 12～ 3 5 1(1 95± 0 6 9)。MES数量及相对强度与INR无相关性。结论 :人工心瓣膜患者脑动脉MES与凝血活性无关 ,提示微栓子物质不是血栓性的     

A Biomechanical Double Sac (Pericardium-Pebax) for Specially Shaped Artificial Ventricles: A Computerized Study to Evaluate Its Mechanical and Volumetric Properties

Abstract: For original ovoid shaped artificial ventricles. a biomechanical double sac consisting of a biological sac (porcine pericardium) as the blood contact interface and a synthetic sac (Pebax 3533) as the mechanical support to assume systolic-diastolic dynamic constraints was conceived. The volumetric and mechanical properties were assessed with a three-dimensional modeling of Pebax sacs and computerized simulations of their systolic distortions for both right and left ventricular configurations. The stresses and strains of these sacs were represented as quantitative mappings for a maximum end-systolic state and were below the respective threshold values above which the Pebax material is jeopardized for permanent structure impairment. After fatigue tests applied on Pebax strips under the alleged working conditions of Pebax sacs, the material structure was unchanged and maintained its intrinsic mechanical properties. The theoretical maximum stroke volumes were 74.4 cm³ and 62.4 cm for the left and right ventricular configurations, respectively. With these mechanical and volumetric features, the biomechanical double sac concept was considered valid and could be provided for a consequent specific total artificial heart.     

Aldose reductase inhibition with imirestat — effects on impulse conduction and insulin-stimulation of Na+/K+-adenosine triphosphatase activity in sciatic nerves of streptozotocin-diabetic rats

Summary This study describes reduced motor nerve conduction velocity and increased resistance to hypoxia-induced conduction failure in sciatic nerves of rats after four weeks of streptozotocin-induced diabetes (both effects were significant at p <0.05). These changes occurred in the absence of any deficit in the steady-state ouabain-sensitive adenosine triphosphatase (ATPase) activity of sciatic nerve endoneurial homogenates. The addition of 10 nmol/l insulin to endoneurial homogenates from control animals resulted in a 34% increase in ouabain-sensitive ATPase activity and a 19% reduction in ouabain-insensitive ATPase activity (both p <0.01). This stimulation of ouabain-sensitive ATPase activity by insulin did not occur in homogenates from diabetic rats. Treating diabetic rats daily with the aldose reductase inhibitor, imirestat (1 mg/kg) improved nerve conduction velocity (p <0.05) but was without effect upon the resistance to hypoxic conduction blockade or the deficit in insulin-stimulated oubain-sensitive ATPase activity. These data suggest that in streptozotocin-diabetic rats the functional disorders of reduced motor nerve conduction velocity and increased resistance to hypoxic conduction blockade do not share a common aetiology and that impaired nerve conduction is not related to reduced maximal potential oubain-sensitive ATPase activity.     

Assessment of exposure to arsenic among smelter workers: A five-year follow-up

In a group of 43 smelter workers exposed to inorganic arsenic dust for 13-45 years, nerve conduction velocities (NCVs) were significantly lower in two peripheral nerves as compared with matching referents. With multivariate data analysis, a significant negative correlation was found between cumulative absorption of arsenic and NCV in four examined nerves and the sural amplitude. Clinical symptoms of neuropathy and other symptoms related to arsenic exposure were moderate, though the difference between the groups was significant. The mean total absorption of arsenic was calculated to be less than 5 g, and the maximal absorption about 20 g. These data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels. © 1994 Wiley-Liss, Inc.     

Turbulent stress measurements downstream of three bileaflet heart valve designs in pigs

Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage^®, CarboMedics© Orbis™ Universal and St. Jude Medical^® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred^® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m², and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m² and 15 N/m². In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m² for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes.     

红细胞膜通道力学效应的探讨

在考察红细胞双凹碟形体形成的基础上,讨论了红细胞的输氧功能与红细胞变形的关系,揭示了红细胞膜通道的力学效应:当红细胞呈双凹碟形时,PiPo的地方,红细胞膜通道有释放出氧的现象,其氧的总流率为 J=Lo_2(Pio_2-Poo_2) Lp(Pi-Po) 式中Lo_2为O_2分压差引起的膜通道对氧的流导,PiO_2、Poo_2为膜内外的氧分压;Lp为由于压差引起的膜通道对氧的流导。     

Invasive ventilation in the emergency department: Part 2: Implications for patient safety

The use of mechanical ventilation in the Emergency Department requires adequate resources in order to maintain patient safety and avoid potential risks. Moreover, developments in technology require increased knowledge of mechanical ventilation techniques to address the complexity of decision-making involved. Organisational issues and system factors have the potential to negatively impact on the ability of the emergency service to provide optimum care to patients receiving mechanical ventilation. These issues include staffing and skill-mix, demand on emergency services, role-delineation, scope of practice, and current mechanisms for monitoring of quality and safety. Furthermore, in response to advances in ventilator technology, current education programs for both nursing and medical staff require review to ensure that they provide comprehensive information about the types of ventilation techniques now available and the relative risks and benefits associated with their application.This article is the second in a two-part series and explores the educational and organisational factors that impact upon safety and quality of care delivered to patients receiving mechanical ventilation in the emergency department. Recommendations for future policy development, curriculum review and reporting mechanisms to support further research in the application of mechanical ventilation in the emergency department are made.     

Der operierte mechanische Ileus

Zusammenfassung Von 1972 bis 1983 wurden 351 Patienten wegen eines mechanischen Dünndarm- (n = 256) bzw. Dickdarmileus (n = 95) operiert. Die chirurgische Komplikationsrate betrug beim Dünndarmverschluß 28,1 bzw. beim Dickdarmileus 24,3%, wobei am häufigsten Anastomosendehiscen-zen nach Resektionen (17,7% bzw. 53,8%), Enterotomien (5,8%/27,2%), Platzbäuche (3,5%/4,2%) und ein Re-Ileus (5,5%/3,2%) vorlagen. Die internistischen Komplikationen (postop. Pneumonien, Lungenembolien, kardiale Dekompensationen etc.) betrugen 17,9% bzw. 22,1 %. Die perioperative Letalität lag beim Dünndarmileus bei 20,6% und beim Dickdarmileus bei 33,4%. Als Schlußfolgerungen dieser retrospektiven Analyse ergaben sich die frühzeitige, perioperative, intensiv-medizinische Behandlung, die generelle Thrombose-, Pneumonie- und StreBulcusprophylaxe, die exakte, präoperative Röntgendiagnostik, die strenge Indikationsstellung für Enterotomien und Resektionen, das dreizeitige Vorgehen beim linksseitigen Dickdarmileus, die Inkontinuitätsresektion nach Hartmann bei entzündlichen Prozessen im Sigmabereich und die innere Dünndarmschienung bei Peritonitis bzw. ausgedehnten Adhäsionen. Dadurch konnte seit Anfang 1984 die Komplikationsbzw. Letalitätsrate beim Dünndarmileus (n = 64) auf 9,4% bzw. 4,7% und beim Dickdarmileus (n = 20) auf 10% bzw. 5% gesenkt werden.

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Experiences with operations of mechanical ileus

Summary Between 1972 and 1983 a total of 351 patients was operated suffering from mechanical occlusion of the small intestine (n = 256) and of the colon (n = 95). The surgical complication rate amounted to 28.1% in cases of small intestine ileus and to 24.3% in cases of colon ileus; the most frequent complications were anastomotic dehiscences following resections (small intestine 17.7%/colon 33.8%), enterotomies (5.8%/27.2%), abdominal wall ruptures (3.5%/4.2%) and re-ileus (5.5%/3.2%). The medical complication rate (postop. pneumonia, pulmonary embolism, cardial decompensation etc.) amounted to 17.7% resp. 22.1%. All these complications carried a mortality of 20.6% in small intestine ileus and of 30.4% in colon ileus. The consequences of this retrospective analysis resulted in: early intensive care treatment, general perioperative thrombosis-, pneumonia- and stress ulcer prophylaxis, exact preoperative radiological diagnosis, strict indications for enterotomies and resections, sole transversostomy in stage of ileus for the left-sided colon obstruction caused by carcinoma, discontinuity resection by Hartmann in cases of inflammatory or perforated large bowel stenoses and tube decompression of the small bowel in cases of peritonitis or wide-spread adhesions. Since 1984 we could prospectively decrease the complication resp. mortality rate of the small intestine ileus (n = 64) to 9.4% resp. 4.7% and of the colon ileus (n = 20) to 10% resp. 5%.

     

院前紧急气管插管与机械通气24例临床分析

目的总结紧急气管插管与机械通气在院前急救中应用的经验,以期提高院前急救水平。方法回顾性分析24例院前气管插管与机械通气抢救心搏呼吸骤停病人的临床资料。结果24例病人气管内插管均获成功,成功率100%。完成气管内插管的时间是15s～60s,平均时间(25±15)s。心搏、自主呼吸恢复4例(16.7%),心搏恢复8例(33.3%);心搏及自主呼吸均未恢复12例(50.0%)。结论气管插管与机械通气是急诊抢救危重病人的基础,对保证进一步心肺复苏、挽留手术机会以及提高危重患者抢救成功率有重要意义。要加强对抢救人员进行紧急气管插管和机械通气的培训。     

TOCP染毒母鸡的神经电生理研究

对TOCP染毒母鸡进行为期7周的神经电生理监测,结果表明,TOCP主要影响远端周围神经,导致坐骨神经远端MCV和SCV减慢及腓肠肌EMG失神经样改变,而胫后神经H反射及重复电刺激无明显异常。