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Reperfusion injury, sometimes called ischemia-reperfusion injury (IRI) or reoxygenation injury, is the tissue damage caused when blood supply returns to tissue (re-+ perfusion) after a period of ischemia or lack of oxygen (anoxia or hypoxia).
The cause of inadequate tissue perfusion (blood delivery to tissues) in distributive shock is a lack of normal responsiveness of blood vessels to vasoconstrictive agents and direct vasodilation. [4] There are four types of distributive shock.
Hypovolemia can be recognized by a fast heart rate, low blood pressure, [12] and the absence of perfusion as assessed by skin signs (skin turning pale) and/or capillary refill on forehead, lips and nail beds. The patient may feel dizzy, faint, nauseated, or very thirsty. These signs are also characteristic of most types of shock. [13]
Physiologic dead space cannot change as it is ventilation without perfusion. A shunt is a perfusion without ventilation within a lung region. [citation needed] Low tidal volume ventilation was the primary independent variable associated with reduced mortality in the NIH-sponsored ARDSNet trial of tidal volume in ARDS.
By widening the blood vessels, the tissue allows greater perfusion. By contrast, in the lungs , the response to hypoxia is vasoconstriction. This is known as hypoxic pulmonary vasoconstriction , or "HPV", and has the effect of redirecting blood away from poorly ventilated regions, which helps match perfusion to ventilation, giving a more even ...
When high pressure is pushing on the walls of narrowed blood vessels, fluid leaves the inside of blood vessels and moves to the space just outside. This impairs necessary blood flow and cuts off circulating oxygen, which can lead to tissue death and permanent damage to the brain, heart, arteries, and kidneys.
In medical and surgical therapy, revascularization is the restoration of perfusion to a body part or organ that has had ischemia. It is typically accomplished by surgical means. [ 1 ] Vascular bypass and angioplasty are the two primary means of revascularization.
A Lindbergh perfusion pump, c. 1935, an early device for simulating natural perfusion. Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, [1] usually referring to the delivery of blood to a capillary bed in tissue. Perfusion may also refer to fixation via perfusion, used in histological ...