Interpretation of venous occlusion plethysmography using a nonlinear model

Venous occlusion plethysmography (VOP) is a noninvasive technique widely employed for the detection of deep-vein thrombosis. Previous reports that VOP outflow curves are closely fit by a first-order exponential suggest that venous compliance and resistance are nearly constant. Typically, however, the venous compliance function has a sigmoid shape; in addition, the resistance in a collapsing tube must increase. This paradox was resolved by the surprising finding that for realistic nonlinear compliance and resistance these nonlinearities cancel, producing a quasilinear venous outflow that approximates a simple exponential.     

急性肺血栓栓塞症兔TNF-α、IL-8、IL-10水平及地塞米松的影响

目的:探讨兔急性肺血栓栓塞症(PTE)时血浆及支气管肺泡灌洗液(BALF)中TNF-α,IL-8、IL-10的水平和地塞米松(Dex)的影响。方法:采用自体血栓回输法建立兔急性PTF模型。36只兔随机分为对照组、Dex治疗组和PTE模型组。用ELISA方法检测上述细胞因子(CK)水平,术毕肺组织行病理观察。结果:栓塞后上述CK均有升高,治疗后TNF-α、IL-8均有下降,IL-10变化不明显。组织病理学可见栓塞后肺动脉内血栓形成,肺组织萎缩、出血、炎性反应明显,Dex治疗后肺组织病理改变明显减轻。结论:PTE后促炎性CK在引起肺部炎性反应和肺组织及肺动脉病损中起了重要作用,抗炎治疗可以明显减轻CK引起的这种损伤。抗炎治疗能降低PTE急性期病死率,改善远期预后,CK可能起了很重要的作用。     

Role of Relative Changes in Caval Flows for Evaluation of Right Atrial Pressure Shifts Induced by Nitroglycerin

Experiments on cats treated with nitroglycerin showed dynamic relationship between changes in caval venous flows: blood flow increased in the superior vena cava and decreased in the inferior vena cava. Blood pressure in the right atrium either decreased, or increased. No significant changes in total venous return were observed during maximum shifts in right atrial pressure, while contractility of the right ventricular myocardium usually decreased. Our findings suggest that the direction of the right atrial pressure shifts induced by nitroglycerin does not depend on venous return, but is determined by the prevalence of flow changes in the superior vena cava or inferior vena cava.     

Three novel PROC gene lesions causing protein C deficiency

Hallam PJ, Mannucci P, Tripodi A, Bevan D, Laursen B, Tengborn L, Wacey A, Cooper DN. Three novel PROC gene lesions causing protein C deficiency. Clin Genet 1998: 54: 231–233. 0 Munksgaard, 1998
Missense mutations. three of them novel (Am210→Val, Asn248→ Ile, Ah355→Val), were found in the protein c ( PROC ) genes of 7 patients with inherited protein C deficiency associated with venous thrombosis. Comparison with the phenotypic effects of mutations in the analogous residues of factor IX causing hdernophilia B and the use of molecular modelling has provided explanations as to how these lesions might alter either the structure, function or secretion of the protein C molecules encoded.     

Effects of dynamic leg exercise on subcutaneous blood flow rate in the lower limb of man

Subcutaneous blood flow (SBF) was studied simultaneously in the upper arm at heart level and in the lower limb during positional changes and during leg exercise in seven healthy males. SBF was estimated by local clearance of ‘“Xenon registered by portable cadmium telluride detectors. Venous pressure was recorded directly on dorsum on the foot. Changinr the position from supine to head-up tilt, SBF decreased by 43 % (P < 0.01) at the arm level, 40% at the thigh (P < 0.01), 47% at the calf (P < 0.01) and decreased by 51 % at the ankle level (P < 0.01). Performing 20 heel-raisings per min in nearly erect posture, SBF increased by 96% at the thigh (P < 0.01), 25% at the calf (P > 0.1) and increased by 18% at the ankle level (P > 0.1). At 40 heel-raisings per min SBF increased by 99% at the thigh (P < 0.0 1), 121 % at the calf (P < 0.0 1), but only 44% at the ankle level (P > 0.1). During leg exercise subcutaneous vascular resistance was significantly increased at arm and ankle levels. In contrast, a vasodilatory response was noticed at the thigh and calf levels and seemed associated with a decrease in local venous pressure to below the trigger level of the sympathetic veno-arteriolar reflex mechanism. In conclusion, SBF in the lower limb of man was increased during exercise. The increase in SBF could only partly be ascribed to the concomitant increase in perfusion pressure. The local blood flow response seemed modified by changes in sympathetic nervous activity and metabolic rate.     

Estimation of central venous pressure by measurement of proximal axillary venous pressure using a "half-way" catheter

The pressure in the proximal axillary vein (AVP) was compared with central venous pressure (CVP) in eight patients during and after elective abdominal surgery. Both pressures were recorded from soft, elastic, polyurethane catheters inserted in the basilic or cephalic veins ("half-way" catheters), punctured at the fossa cubiti (AVP), and via the right jugular vein (CVP). The AVP and CVP were recorded simultaneously using hydrostatic, conventional disposable venous pressure measurement sets. The measurements were performed during intermittent positive pressure ventilation with positive end-expiratory pressure from 0 to 7.5 cmH2O (0-0.74 kPa), as well as during spontaneous breathing. During both controlled and spontaneous respiration, small mean differences (0.2-1.0 cmH2O) (0.02-0.1 kPa), and a highly significant (P less than 0.001) positive correlation between CVP- and AVP-values were found. An increase of 1 cmH2O (0.10 kPa) in the CVP was associated with an increment of practically identical order (0.99-1.04 cmH2O) (0.10-0.11 kPa) in the AVP. The results suggest that monitoring of the AVP by a basilic "half-way" catheter produces diagnostic information similar to that from the measurement of the CVP from subclavian, external or internal jugular, as well as "long-way" brachial catheter, with no risk of the major mechanical complications which accompany the use of the latter catheters.     

恶性肿瘤合并静脉血栓栓塞症患者危险因素分析

目的：分析恶性肿瘤合并静脉血栓栓塞症（VTE）患者的危险因素。方法：选取2020年1月至2022年1月陆军第73集团军医院进行治疗的133例恶性肿瘤患者,对患者一般资料进行回顾性分析,比较恶性肿瘤组患者及恶性肿瘤合并VTE组患者一般资料,通过多因素logistic回归分析明确恶性肿瘤合并VTE的危险因素,比较两组患者1年死亡率。结果：两组患者肿瘤分期、冠心病、化疗、合并感染、激素治疗、中心静脉置管构成比及纤维蛋白原（FIB）、D–二聚体（D–D）、活化部分凝血活酶时间（APTT）、血管性血友病因子（vWF）水平比较,差异具有统计学意义（P <0.05）;多因素logistic回归分析结果表明肿瘤分期Ⅲ～Ⅳ期、有冠心病、有化疗、有感染、有激素治疗及有中心静脉置管、血浆D–D水平高为恶性肿瘤合并VTE危险因素,差异具有统计学意义（P <0.05）。多因素logistic回归分析结果表明,肿瘤分期Ⅲ～Ⅳ期、有冠心病、有化疗、有感染、有激素治疗及有中心静脉置管、血浆D–D水平高为恶性肿瘤合并VTE危险因素（P <0.05）;恶性肿瘤合并VTE组患者1年死亡率明显高于恶性肿瘤组...     

不同疗法对活动性肝硬化门静脉高压症大出血的疗效比较

目的　观察断流术、分流术和保守治疗对活动性肝硬化门静脉高压症大出血的疗效。方法　 112例随机分组 ,分别进行断流术 (5 7例 )、分流术 (19例 )和保守治疗 (36例 )。于治疗前后测定门静脉血流量 (PVF)和自由门静脉压 (FPP) ,随访了解患者的肝炎稳定率、再出血率和病死率等。结果　术后分流组的PVF较断流组显著减少 (P <0 .0 5 )。治疗后 1年内 ,断流、分流和保守治疗各组的肝炎稳定率分别是 35 .1%、10 .5 %和 13.9% (断流组显著高于其它两组 ,均P <0 .0 5 )。 3组患者的再出血率分别是 3.5 %、5 .3%和 2 7.8% (两手术组显著低于保守治疗组分别为P <0 .0 0 1和P <0 .0 5 )。结论　此类患者的治疗以采用断流术为宜     

股浅静脉戴戒术治疗原发性下肢深静脉瓣膜功能不全

目的 用股浅静脉戴戒术治疗原发性下肢深静脉瓣膜功能不全。方法 本文应用股浅静脉戴戒术治疗原发性下肢深静脉瓣膜功能不全34例,并应用无创性光电容积描记（PPG）结合临床症状改善状况对手术疗效进行评估。结果 手术前后静脉返流时间（VRT）有显著差异（P＜0．01）,临床症状改善。结论 股浅静脉戴戒术是治疗下肢深静静脉瓣膜功能轻度不全的有效方法,PPG检查结合临床改善程度是判断手术疗效更有效的方法。