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Duration of bleeding (according to Duke)
Last reviewed: 23.04.2024
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The duration of bleeding (according to Duke) is a specific technique for assessing the state of the circulatory system, more precisely - the vessels. Normally, according to this method, the period from the beginning to the stop of blood loss should be no more than three minutes.
Hemostasis is a very important function, a whole biological complex, which is aimed at timely stopping blood, so that the body does not lose it above the physiological norm. By mechanisms of regulation of hemorrhage, hemostasis is divided into vascular-platelet or primary and secondary, proper coagulation of blood flow.
The duration of bleeding (according to Duke) is an evaluation of the state of thrombocytes. If the vascular walls are damaged, then ideally platelets should be activated immediately to participate in clotting - hemocoagulation. Vessels with normal elasticity spasmodiruyutsya and clogged aggregated platelets (aggregation - gluing, clumping cells). Thus, the vessel is closed by a primary, very important formation called the "white thrombus".
[How is the sample performed?
Often the duration of bleeding (according to Duke) is performed by a special needle, it is also called the needle of Frank. It consists of a hollow body with a trigger. On the one hand, the needle has a coupling for a spring, on the other a small tip. The needle of this design is very convenient, since the lab technician can regulate the exact depth of the puncture. With the help of pulling the trigger, when the spring is straightened, a very small puncture is made. The Duque test provides for a fence of not more than 1 ml of material, that is, blood. The puncture is done in the finger, most often in the nameless, or in the earlobe.
Are there alternative ways to determine the duration of bleeding?
The duration of bleeding (according to Duke) is not the only method in the modern diagnostic complex. Often, instead of scarifying the lobe of the human ear, laboratory technicians use more sophisticated and sensitive methods. Artificially provoked difficulties for venous outflow - stasis (often with the aid of a device for monitoring blood pressure), then a puncture is made in the upper zone of the forearm by the scarifier. Special drops of blood are dripped every 20-30 seconds with special sterile wipes. Normally, after three minutes on the last napkin, the spots become small, and after another two minutes the bleeding stops.
Nevertheless, the duration of bleeding (according to Duke) as a method, tested by the century, has the right to exist. Moreover, hundreds of laboratories continue to use this test, and doctors are used to trusting this technique, using calculations to clarify the diagnosis and adjust therapeutic measures.
With the help of which indicators is primary hemostasis evaluated?
In addition, as determined by the duration of bleeding (according to Duke), platelet activity is also assessed using:
- Calculation of the number of platelets;
- Calculation of a specific platelet formula;
- Estimations of aggregation of adenosine diphosphate (ADP) and platelets;
- Assessing the ability of platelets to aggregate with collagen;
- Determination of the possibility of platelets to aggregate with adrenaline;
- Coagulation estimates are the activity of the von Willebrand factor.
The method of determining the time at which a blockage of damaged vessels is formed was developed by the American scientist, pathologist William Duke at the beginning of the 20th century. Earlier, the sample was taken by a scarifier or a thin needle from the earlobe, later - from a finger.
How is the duration of bleeding estimated (according to Duke)?
Normal hemostasis is able to cope with blood loss, the more microscopic it is, in two or three minutes. If the clotting is delayed, respectively, and the duration of bleeding (according to Duke) will be greater. This may indicate a background of other indicators deviating from the norm, about liver pathologies, hemophilia and other diseases. It should be noted that the period that is measured may depend on the blood sampling site - the tip of the finger or ear.