CTI和3G技术在120急救指挥中心的应用

介绍了120急救指挥中心的结构、计算机电话一体化和卫星定位系统、地理信息系统以及无线通讯系统的功能，分析了CTI和3G技术在120急救指挥中心的实际应用和取得的成效。     

Hypercoagulation following brain death cannot be reversed by the neutralization of systemic tissue factor

Background

Cerebral injury and brain death is associated with apparent hypercoagulation and poor organ outcome. This experimental study challenges the hypotheses that i) brain death causes hypercoagulation and microvascular thrombosis and that ii) neutralizing systemic tissue factor (TF) by in vitro addition of a TF inhibitor (recombinant active site-inhibited factor VIIa (ASIS)) can reverse the hypercoagulable profile.

Methods

Using a validated pig model of intracranial hemorrhage and brain death, 20 pigs were randomized to either control or brain death. The primary endpoints were coagulation parameters measured with whole blood thromboelastometry (ROTEM), thrombin generation and a porcine TF-sensitive plasma clotting time assay. In vitro spiking experiments with ASIS were performed in parallel with the latter two assessments. The kidneys were examined histologically for microvascular thromboses.

Results

Brain death induced hypercoagulation, as demonstrated with ROTEM, thrombin generation, and reduced TF-sensitive plasma clotting time. In vitro inhibition of TF with ASIS did not reverse the hypercoagulation. No microvascular thromboses were found in the kidneys.

Conclusion

Brain death causes hypercoagulation; however, inhibition of TF does not reverse the coagulopathy. Thus, TF release does not seem to be the primary cause of this hypercoagulation. Minor changes in the levels of protein C suggest that the protein C pathway may be linked to the observed coagulopathy.     

现代120急救指挥中心的设计与建设体会

目的 采用现代技术,建立一个高水平的120急救指挥中心。方法 将计算机网络、卫星定位系统、地理信息系统、计算机电话一体化、数字录音系统有机结合起来,成为一个安全、可靠的综合实体。结果 120急救指挥调度目标清晰,有条不紊,服务质量更高。结论 现代技术能有效提高120急救指挥中心的急救效率和成功率。     

Evaluation of the procoagulant activity in the plasma of cancer patients using a thrombin generation assay

Introduction

Circulating microparticles are reported to play a role in cancer hypercoagulability. The procoagulant properties of microparticles derive from the amount of tissue factor and/or phosphatidylserine that they can expose. The aim of our study is to assess the procoagulant activity, including microparticles’ activity, in the plasma of newly diagnosed cancer patients with a simple assay, easy to implement in the laboratory.

Material and methods

Newly diagnosed cancer patients (n = 31) before the start of anticoagulant or chemotherapy were compared to matched controls. We used a thrombin generation assay in four conditions: 1: addition of 1pM tissue factor and 4 μM procoagulant phospholipids, 2: without any trigger, 3 and 4: addition of tissue factor or procoagulant phospholipids alone respectively.

Results

When we added only phospholipids, so that thrombin generation is dependent upon endogenous tissue factor, the lag time was significantly shorter in cancer patients. When we added only tissue factor, i.e. made the results dependent upon phospholipids, the endogenous thrombin potential, the peak, and the velocity index were significantly higher and the time-to-peak was significantly shorter. This suggests that the plasma of cancer patients contained a higher activity of endogenous phospholipids and/or tissue factor which may be borne by microparticles.

Conclusion

This new simple methodology can demonstrate a procoagulant activity in the plasma of newly diagnosed cancer patients which can be explained by higher procoagulant phospholipids and tissue factor activity and thus, brings potentially useful information that current coagulation tests cannot provide.     

CTI技术及其在医学领域中的应用

本文首先描述了CTI技术，并介绍其在医学领域中的应用，最后给出了一个具体的医疗信息声讯系统方案。     

Inter-relationships of atrial fibrillation and atrial flutter mechanisms and clinical implications

There is a close interrelationship between atrial fibrillation (AF) and atrial flutter (AFL). Atrial fibrillation of variable duration precedes the onset of AFL in almost all instances; during AF, the functional components needed to complete the AFL re-entrant circuit, principally a line of block (LoB) between the vena cavae, are formed; if this LoB does not form, classical AFL does not develop. In contrast, there seems to be a spectrum of atrial re-entrant circuits (drivers) of short cycle lengths (CLs) (i.e., AFL). When the CL of the AFL re-entrant circuit is so short that it will only activate portions of the atria in a 1:1 manner, the rest of the atria will be activated rapidly but irregularly (i.e., via fibrillatory conduction), resulting in AF. In short, there are probably several mechanisms of AF, 1 of which is due to a very rapid AFL causing fibrillatory conduction. All of these interactions of AF and AFL have important clinical implications.     

Antithrombotic effects of PAR1 and PAR4 antagonists evaluated under flow and static conditions

Introduction

Thrombin-mediated activation of human platelets involves the G-protein-coupled protease-activated receptors PAR1 and PAR4. Inhibition of PAR1 and/or PAR4 is thought to modulate platelet activation and subsequent procoagulant reactions. However, the antithrombotic effects of PAR1 and PAR4 antagonism have not been fully elucidated, particularly under flow conditions.

Materials and Methods

A microchip-based flow chamber system was used to evaluate the influence of SCH79797 (PAR1 antagonist) and YD-3 (PAR4 antagonist) on thrombus formation mediated by collagen and tissue thromboplastin at shear rates simulating those experienced in small- to medium-sized arteries (600 s^- 1) and large arteries and small veins (240 s^- 1).

Results

At a shear rate of 600 s^- 1, SCH79797 (10 μM) efficiently reduced fibrin-rich platelet thrombi and significantly delayed occlusion of the flow chamber capillary (1.44 fold of control; P < 0.001). The inhibitory activity of SCH79797 was diminished at 240 s^- 1. YD-3 (20 μM) had no significant effect at either shear rate. The antithrombotic effects of SCH79797 were significantly augmented when combined with aspirin and AR-C66096 (P2Y₁₂ antagonist), but not with YD-3. In contrast, no significant inhibition of tissue factor-induced clot formation under static conditions was observed in blood treated with SCH79797 and YD-3, although thrombin generation in platelet-rich plasma was weakly delayed by these antagonists.

Conclusions

Our results suggest that the antithrombotic activities of PAR1 and/or PAR4 antagonism is influenced by shear conditions as well as by combined platelet inhibition with aspirin and a P2Y₁₂-antagonist.     

Women with unexplained recurrent pregnancy loss do not have evidence of an underlying prothrombotic state: Experience with calibrated automated thrombography and rotational thromboelastometry

Introduction

Where unexplained recurrent pregnancy loss (RPL) is attributed to an underlying maternal prothrombotic state, empirical prophylactic anticoagulation may be recommended.

Materials and Methods

In the present study we used calibrated automated thrombography and rotational thromboelastometry to determine the procoagulant potential of these women as a rationale for anticoagulation. Fifty women with ≥ three consecutive unexplained losses prior to 14 weeks’ gestation or one loss after this time were compared with forty-one parous women with no miscarriages. Exclusion criteria included antiphospholipid syndrome, inherited thrombophilia and prior venous thromboembolism. Thrombin generation in platelet poor plasma and whole blood thromboelastometry was performed outside pregnancy to determine the presence or not of an underlying prothrombotic state.

Results

Peak thrombin and endogenous thrombin potential were not significantly increased in subjects relative to controls. The use of low tissue factor (1 pM) to better reflect physiological conditions and assay modification to better assess the protein C pathway (5 pM in the presence of thrombomodulin) provided no additional discrimination. Consistent results were shown with thromboelastometry; mean parameters were equivalent between subjects and controls.

Conclusions

These data demonstrate that global coagulation assays provide no evidence of an underlying hypercoagulable state in women with unexplained RPL; this is in keeping with the results of recent randomised controlled trials and strengthens the evidence base against use of anticoagulants in this setting.     

Failure of hybrid therapy for the prevention of long-term recurrence of atrial fibrillation

Objectives

To determine the long-term effectiveness of hybrid therapy in the control of atrial fibrillation (AF) as well as the differences in clinical outcomes between patients with antiarrhythmic drug atrial flutter (AAD-AFl), those with coexistent AFl and AF, and isolated AFl.

Methods

Four hundred eight patients who consecutively underwent cavotricuspid isthmus (CTI) ablation between 1998 and 2010 were followed for 5.9 years. Twenty-seven patients had AAD-AF1 (Group 1): they had AF but not AFl at baseline but on AAD therapy they showed typical AFl. They underwent CTI ablation and continued with AAD therapy, 96 patients had coexistent AF1 and AF at baseline (Group 2) and continued with AAD therapy at the discretion of their cardiologists and 284 patients had isolated AFl (Group 3).

Results

AF recurred in the majority of the AAD-AF1 patients (74%, incident density rate (IDR): 19.1/100 person-years). This incidence rate was similar to the recurrence rate of AF in patients with coexistent AFl and AF (59%, IDR: 19.2/100 person-years). The patients in Group 1 had a similar IDR of stroke as Group 2 and a slightly higher rate than Group 3. There were no significant differences in the IDR for death among Groups 1, 2 and 3.

Conclusions

Hybrid therapy was not effective for long-term control of AF. The clinical outcomes (AF, stroke and death) were similar for AAD-AF1 patients and patients with coexistent AF and AFl.     

The effects of pneumatic tube system transport on ROTEM analysis and contact activation assessed by thrombin generation test

Thromboelastometry (ROTEM) is a popular point-of-care test. It generates results quickly and may benefit individualised guided haemostatic therapy. However, processing of specimens by non-technicians might decrease the quality and reproducibility of results. Centralised laboratory equipment receiving specimens through a pneumatic tube system (PTS) could avoid this. This study aimed to evaluate the influence of PTS transport on ROTEM results and its contribution to contact activation assessed by thrombin generation (TG).

Methods

Specimens from 44 patients were drawn immediately after arterial puncture. Two were anticoagulated by citrate and two by citrate/corn trypsin inhibitor, a Factor XIIa pathway inhibitor. Both types of samples were transported by walking and PTS. Subsequently, analysis was performed: ROTEM on citrated blood, and TG on citrated and corn trypsin inhibitor (CTI) blood using either 0 or 1 pM tissue factor (TF).

Results

In ROTEM analysis the NATEM assay showed significant differences. The EXTEM assay revealed small significant differences for clot formation time: 65 seconds (SD ± 20) versus 67 seconds (SD ± 17), and alpha angle 79° (SD ± 3) versus 77° (SD ± 3). The results remained within reference range. TG was not significantly affected by the type of tube transport, independent of the amount of TF.

Conclusion

PTS for ROTEM analysis is feasible except for NATEM assays. The amount of contact activation via Factor XIIa in terms of TG is independent of transport type. However, due to the different characteristics of pneumatic systems, hospitals should check its impact on the results before introducing this route of transport.