Sonoclot coagulation and platelet function analyzer (Sonoclot coagulation and platelet function analyzer, SCA, SIENCO, Inc, USA) by Von Kaulla et invented in 1975, is mainly used for the coagulation and platelet function test in vitro. At present, the instrument in cardiovascular surgery, liver transplant and other blood loss big surgery, and pediatrics, intensive care and hemostatic research in the field of applied more and more, has gradually become an important clinical hemostatic, accurate and fast inspection tools. This article makes a brief introduction to the principle and application of the instrument.
A, normal hemostasis process
Blood vessels are damaged, the organization factors into the blood, blood and blood vessels in subcutaneous collagen contact can start the exogenous and endogenous clotting system respectively, and through the common way to eventually generate thrombin, under the action of thrombin and fibrinogen to fibrin monomer fibrin monomer polymerization for fibrin polymer again, finally make blood a gel. This is commonly referred to as the coagulation cascade.
In the process of blood coagulation, platelet also plays a very important role in [1]. First, hemal wall after damage, platelets under the VW factors mediated adhesion in subcutaneous collagen, and was formed by subcutaneous tissue and local thrombin activation, release reaction, the release of ADP and TXA2, thus further attract platelet aggregation. Activated platelets and fibrin common white thrombosis. After coagulation clot formation, platelet contractile proteins by fibrin network structure, make the blood clots occur contraction (clotting contraction), it can greatly strengthen the strength of a blood clot, finally have the effect of the bleeding. When a blood clot or by gel state into a solid. In addition, platelets for coagulation cascade is accelerated and catalytic role. Visible, platelets for normal hemostatic functions play an important role.
At the same time of coagulation system startup, fibrinolytic and anticoagulation system is activated, the bleeding and anticoagulant system in the new equilibrium point to reach a new dynamic balance.
Second, the principle of Sonoclot analyzer and testing parameters
Sonoclot coagulation and platelet function analyzer (figure 1) can provide the whole materials about the blood samples in vitro hemostatic process, the test parameters can reflect the blood coagulation system activation, fibrin gel formation and fibrinolysis, and clotting contraction related information. Its working principle is: disposable plastic which connect with the ultrasonic sensor probe in specimens of anticoagulant fresh blood (0.36 ml) at 200 hz frequency vibrated, encountered resistance were recorded, converted to analog signals, with coagulation signal (clot signal) displayed by a computer or printer. It is essentially for blood specimen the real-time measuring viscoelastic change in the solidification process (FIG. 2, 3).
The test parameters include: ACT (SonAct, activated clotting time) blood specimens of liquid time, normal for 85-145 - s, mainly reflect the status of endogenous clotting system (figure 4). CR (clot rate, blood coagulation rate), the first slope of curve, reflect the rate of fibrin formation, indirectly reflect the level of fibrinogen (figure 5), normal 15 to 45 clot signal/min. After coagulation clot formation, in under the function of platelet and fibrin, contraction, as the blood clot strength, sonoclot tag curve, and gradually reached its peak, as the clotting contraction, blood clots may from the surface of the probe and decreased sonoclot mark curve (figure 6).
TP (time to peak, peak time), blood coagulation signal curve peak time, the peak composed of fibrin and platelets interaction, can reflect the level of fibrinogen and platelet amount and function of normal < 30 min; MCS (maximal clot signal, maximum blood coagulation markers) on behalf of the probe is the biggest resistance value, its highly reflect the strength of the blood clotting contraction, normal 70-90 clot signal (figure 7). PF (platelet function, platelet function), platelet function, are connected to the analyzer by the Signature of the viewer software on the basis of blood specimen end of liquid phase (fibrin) polymer formation after the intensity of the blood clotting contraction and speed (clotting contraction sonoclot curve of each point in the process of calculus value) to calculate the relative value. Platelet function besides PF, also can be made of TP and MCS. Normal Sonoclot curve is usually visible two obvious peak, the first peak reflects the fibrinogen into a fibrous protein, its rise more steep (CR), shows that the higher the concentration of the fibrinogen, the faster it into a fibrous protein; After the first peak of the curve fell to the second peak after the formation and the decline of fibrin and platelets produce interaction, the result of blood clots occur contraction; The second peak is higher, the more steep, the more that clotting contraction, the greater the concentration of fibrinogen, integrated embodiment of platelets in blood coagulation (reflect the amount of blood platelet, function and its interaction with fibrin), the better. Visible, Sonoclot analyzer not only can reflect the status of the clotting factors, but also reflects the number and function of platelet.
Third, Sonoclot test with conventional coagulation test
Normal function of blood coagulation tests include: coagulation phase (APTT, PT and CT, TT, FIB) and platelet count (PLT). The blood coagulation phase can only reflect the status of blood coagulation factors, and cannot reflect the whole picture of the whole process of blood coagulation; The platelet count was quantitative test of the platelet, and can not reflect the function of platelet. And is Sonoclot analyzer is a reflection of the coagulation cascade and the comprehensive situation of the whole blood coagulation system, namely blood coagulation factor and the interaction of platelet and this is normal coagulation function is unable to achieve. More important, so far still lack a kind of suitable for clinical detection of platelet function method [2]. The classic way to detect the platelet function is under the condition of adding different inductive substance, the platelet function test, but this method, complex and time-consuming, only suitable for in the lab. And Sonoclot analyzer has good correlation with function of platelet parameters, reports said Sonoclot analyzer measuring Tp and the platelet aggregation induced by collagen, platelet count and fibrinogen levels has multiple linear correlation (r = 0.742) [2]. To bed of blood coagulation and platelet function for fast and accurate testing provides a feasible method. And, Sonoclot test is used to predict the sensitivity and accuracy of postoperative blood coagulation dysfunction is superior to the normal function of blood coagulation tests [3, 4].
Four, Sonoclot analyzer of clinical application
1. Anticoagulation management: cardiovascular surgery and anticoagulant therapy, Sonoclot analyzer can accurately reflect the anticoagulant effect, so as to provide objective basis for the use of anticoagulants (figure 8).
2. Perioperative blood coagulation function test: in liver transplantation (figure 9) [5], cardiovascular function abnormal bleeding after the operation of [4] and other blood loss in the operation, and identify causes of postoperative bleeding (figure 10) [6], Sonoclot analyzer can provide timely information about blood coagulation and platelet function, to provide reliable basis for clinicians to deal with, to guide the use of blood products, targeted intervention of coagulant function abnormality, reduce the waste of blood products.
3. The auxiliary diagnosis of DIC: DIC is intensive care and emergency rescue in the process of common disease, its diagnosis mainly depends on clinical doctor to the patient's clinical symptoms and some laboratory indexes comprehensive judgment. Sonoclot analyzer can in a short period of time (20-30 minutes) to provide information about intuitive DIC, help doctors quickly accurate judgement (figure 11).
4. High coagulation state recognition: Peck et al. [7] will find Sonoclot inspection and thrombin formation test (TGT) combined with application can make the identification of high coagulation state in 79-100%. For the high condensation state identification and monitoring provides a rapid and simple method.
In addition, because Sonoclot analyzer test takes much less blood (0.36 ml), very suitable for newborns and babies blood coagulation function test.
Sonoclot analyzer provides us with a kind of brand-new, can fast and accurately reflect the condition of blood coagulation system integrated testing method, is that we can only use less health and get more information. But Sonoclot inspection is not the only, the final diagnosis, clinicians should still combines the condition of patients and other inspection index synthetically judgment.