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Paroxysmal supraventricular tachycardia (PSVT) is a type of supraventricular tachycardia, named for its intermittent episodes of abrupt onset and termination. [ 3 ] [ 6 ] Often people have no symptoms. [ 1 ]
Blood tests may be done to rule out specific underlying causes such as hyperthyroidism, pheochromocytomas, or electrolyte abnormalities. [4] A normal resting heart rate is 60 to 100 beats per minute. A resting heart rate of more than 100 beats per minute is defined as a tachycardia.
The body has several feedback mechanisms to maintain adequate blood flow and blood pressure. If blood pressure decreases, the heart beats faster in an attempt to raise it. This is called reflex tachycardia. This can happen in response to a decrease in blood volume (through dehydration or bleeding), or an unexpected change in blood flow.
A newer model of coagulation mechanism explains the intricate combination of cellular and biochemical events that occur during the coagulation process in vivo. Along with the procoagulant and anticoagulant plasma proteins, normal physiologic coagulation requires the presence of two cell types for formation of coagulation complexes: cells that ...
Unlike other blood products demand for platelet transfusions appears to be increasing in several countries around the world. [27] An ageing population, an increase in the number of people with blood cancer , and changes to the management of these cancers are likely the major reasons for the rise in demand for platelets. [ 27 ]
[3] [6] This blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. [3] [6] From the left ventricle, the blood passes through the aortic valve to the aorta. [3] [6] The blood is then distributed to the body through the systemic circulation before returning again to the pulmonary circulation. [3] [6]
A blood substitute (also called artificial blood or blood surrogate) is a substance used to mimic and fulfill some functions of biological blood. It aims to provide an alternative to blood transfusion , which is transferring blood or blood-based products from one person into another.
Even though red blood cells can also be collected in the process, many blood donation organizations do not do so because it takes much longer for the human body to replenish their loss. In addition, some (though not all) centers defer further platelet donations until the red blood cells can be replenished.