Table of contents:
1- What is hemostasis?
2- What does it consist of?
3- How is hemostasis measured?
What is hemostasis?
Hemostasis is the body’s own defense mechanism that acts after trauma or injury. The objective is to prevent blood loss from the interior of the blood vessels. For this reason, the hemostatic system is a fundamental part of the body’s defense.
This procedure prevents blood loss, but also contributes significantly to the repair of tissue and vascular injury and the generation of new tissue. It involves vascular, platelet, plasma and fibrinolytic components.
What does it consist of?
Hemostasis consists of different phases:
1- Primary
Hemostasis begins when there is an injury to the blood vessels. From there, vasoconstriction occurs, which seeks to decrease local blood flow and hemorrhage or thrombosis.
At that moment, platelets are activated, which adhere to the blood vessels and alter their shape to join with more platelets in the area of the lesion. In this way, joining with each other, they form a platelet plug that is initial and has a short-term duration.
2- Secondary
In this phase, the formation of a clot that prevents the blood from flowing out occurs. This occurs due to a chemical modification that renders fibrinogen insoluble to produce large macromolecular aggregates. At this stage the fibrinogen becomes known as fibrin.
In this way the body manages to stop the hemorrhage.
3- Fibrinolysis
In the third stage, the destruction of the platelet plug occurs gradually. In other words, the body is in charge of restoring blood flow.
Although blood clots in most cases are beneficial to the body, since they stop bleeding, in many situations they are generated under unfavorable conditions, such as in cases of genetic defects, drug administration and arteriosclerosis. When this happens it can lead to detrimental health consequences, such as heart attack or stroke.
Hemostasis is a defense mechanism of the organism itself, which acts after trauma.
after trauma or injury.
How is hemostasis measured?
There are different tests that can be performed to determine alterations in hemostasis:
(a) Bleeding time (BT):
Seeks to detect blood clotting by cutting the blood vessels, which contract. That is, it measures the time it takes for platelets to seal the cut.
b) Platelet aggregation test:
It also evaluates primary hemostasis. The patient’s platelets are exposed to multiple substances that induce coagulation.
c) Prothrombin time:
This test studies the time it takes for the clot to form, i.e., it determines whether the factors involved in coagulation are working properly. However, unlike the two previous tests, it focuses on the second phase of hemostasis.
It is usually performed to check the functioning of oral anticoagulants, to analyze the cause of bruising or bleeding, to detect congenital deficiencies or as a preoperative test.
The results of this test are expressed in seconds and the lower limit is usually between 10 and 12 seconds, while the upper limit is between 12 and 14 seconds.