Search results
Results from the WOW.Com Content Network
Severe drops in blood pressure can lead to fainting, with a possibility of injury. Moderate drops in blood pressure can cause confusion/inattention, delirium, and episodes of ataxia. Chronic orthostatic hypotension is associated with cerebral hypoperfusion that may accelerate the pathophysiology of dementia. [5]
In an ischaemic leg, elevation to 15 degrees or 30 degrees for 30 to 60 seconds may cause pallor. (This part of the test checks for elevation pallor.) A vascular angle of less than 20 degrees indicates severe ischaemia. [1] [2] From a sitting position, in normal circulation, the foot will quickly return to a pink colour.
Rarely, ACS can develop after a minor injury or another medical issue. [12] It can also affect the thigh, buttock, hand, abdomen, and foot. [19] [14] The most common cause of acute compartment syndrome is a fractured bone, usually the tibia. [14] [27] Leg compartment syndrome occurs in 1% to 10% of tibial fractures. [6]
Treatment options for PTS include proper leg elevation, compression therapy with elastic stockings, or electrostimulation devices, pharmacotherapy (pentoxifylline), herbal remedies (such as horse chestnut, rutosides), and wound care for leg ulcers. [1] [21] The benefits of compression bandages is unclear. They may be useful to treat edemas. [7]
Acute limb ischemia may also be caused by traumatic disruption of blood flow to a limb, which may present with either hard signs or soft signs of vascular injury. [15] Hard signs include pulsatile bleeding, expanding hematomas (collections of blood), or absent distal pulses, and must be taken to surgery emergently.
When a person is recumbent, or is lying down, blood is redistributed from the lower extremities and abdominal cavity (splanchnic circulation) to the lungs. [5] Failure to accommodate this redistribution results in decreased vital capacity and pulmonary compliance , further causing the shortness of breath experienced in PND.
The major tissues affected are nerves and muscles, where irreversible damage starts to occur after 4–6 hours of cessation of blood supply. [4] Skeletal muscle, the major tissue affected, is still relatively resistant to infarction compared to the heart and brain because its ability to rely on anaerobic metabolism by glycogen stored in the cells may supply the muscle tissue long enough for ...
Hypoxemia is caused by five categories of etiologies: hypoventilation, ventilation/perfusion mismatch, right-to-left shunt, diffusion impairment, and low PO 2. Low PO 2 and hypoventilation are associated with a normal alveolar–arterial gradient (A-a gradient) whereas the other categories are associated with an increased A-a gradient.