Coagulation Time: From 1 Different Sources
(clotting time) the time taken for blood or blood plasma to coagulate (see blood coagulation). When measured under controlled conditions and using appropriate techniques, coagulation times may be used to test the function of the various stages of the blood coagulation process.
See COAGULATION.... clotting time
(DIC) A type of bleeding disorder in which abnormal clotting leads to depletion of coagulation factors in the blood; the consequence may be severe spontaneous bleeding.... disseminated intravascular coagulation
The period during which the biting cycle of a given mosquito species when the largest number of females take blood meals.... peak biting time
The main mechanism by which blood clots are formed, involving a complex series of reactions in the blood plasma (see blood clotting).... coagulation, blood
an endoscopic procedure used predominantly to control bleeding in the gastrointestinal tract. secondary to angiodysplasia and bleeding following polypectomy. Occasionally it is used in the debulking of tumours not amenable to surgery. An intermittent stream of argon gas is delivered through a catheter in the endoscope and ionized by a monopolar electrical current producing a controlled release of thermal energy. This causes coagulation in the adjacent tissues.... argon plasma coagulation
(blood clotting) the process whereby blood is converted from a liquid to a solid state. The process may be initiated by contact of blood with a foreign surface (intrinsic system) or with damaged tissue (extrinsic system). These systems involve the interaction of a variety of substances (*coagulation factors) and lead to the production of the enzyme thrombin, which converts the soluble blood protein *fibrinogen to the insoluble protein *fibrin, forming the blood clot. Finally, fibrin is broken down by the action of *plasmin. Anticoagulants and tissue plasminogen activators act by inhibiting or activating various pathways in this cascade (see illustration). Blood coagulation is an essential mechanism for the arrest of bleeding (*haemostasis). See also platelet activation.... blood coagulation
a quickly performed test to assess the adequacy of circulation in an individual with poor cardiac output. An area of skin is pressed firmly by (say) a fingertip until it loses its colour; the number of seconds for the area to return to its original colour indicates capillary refill time. Normal capillary refill takes around 2 seconds. Slow capillary refill may occur globally in an individual with poor circulation or in a small area (e.g. a toe) in which local circulation is compromised (due, for example, to peripheral vascular disease). This test may not be very useful in people with dark skin.... capillary refill time
(clotting factors) a group of substances present in blood plasma that, under certain circumstances, undergo a series of chemical reactions leading to the conversion of blood from a liquid to a solid state (see blood coagulation). Although they have specific names, most coagulation factors are referred to by an agreed set of Roman numerals (e.g. *Factor VIII, *Factor IX). Lack of any of these factors in the blood results in the inability of the blood to clot. See also haemophilia.... coagulation factors
see cervical intraepithelial neoplasia.... cold coagulation
the time in minutes between a patient with S–T elevation *myocardial infarction reaching the hospital door and inflation of a balloon or other interventional device in the occluded coronary artery. It is a key indicator of the timeliness of an emergency *percutaneous coronary intervention service.... door to balloon time
a type of *electrocoagulation used to arrest haemorrhage or destroy abnormal tissue. A stream of inert gas, such as argon or helium, is ionized, thereby carrying electrical energy to adjacent tissue; there is no physical contact between the plasma coagulation apparatus and the tissue.... plasma coagulation
(PT) the time taken for blood clotting to occur in a sample of blood to which calcium and thromboplastin have been added. A prolonged PT (compared with a control sample) indicates a deficiency of *coagulation factors, which – with calcium and thromboplastin – are required for the conversion of prothrombin to thrombin to occur in the final stages of blood coagulation. Measurement of PT is used to control anticoagulant therapy (e.g. with warfarin). See INR.... prothrombin time
the rapid acquisition and manipulation of ultrasound information from a scanning probe by electronic circuits to enable images to be produced on TV screens almost instantaneously. The operator can place the scanning probe accurately on the region of interest in order to observe its structure and appreciate moving structures within it (see Doppler ultrasound). Using similar techniques, the instantaneous display of other imaging modalities, such as *computerized tomography scanning and *magnetic resonance imaging, can now be achieved. Real-time imaging is useful in guiding *interventional radiology procedures, for example, allowing a needle to be guided accurately as it is passed into the body. It is also useful for observing dynamic physiological activity.... real-time imaging
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