As a medical expert with a focus on neurology, I can tell you that ischemia refers to a deficiency in the blood supply to tissues, particularly the heart or brain. When discussing global cerebral ischemia, we are talking about a situation where the entire brain experiences a lack of blood flow, which can be caused by events such as cardiac arrest. The impact of ischemia on the brain can vary greatly depending on the duration and severity of the blood flow reduction. In some cases, if blood flow is restored quickly, the brain may recover without any lasting damage. However, if the ischemia is prolonged, it can lead to permanent damage due to the death of brain cells from lack of oxygen and nutrients. It's important to note that the term "permanent" in this context means that the damage is not expected to improve over time without medical intervention. However, with advances in medical technology and the understanding of brain plasticity, there can sometimes be improvements in function even after permanent damage has occurred. read more >>

Global cerebral ischemia occurs when blood flow to the brain is stopped or reduced. This is usually triggered by cardiac arrest. ... However, if a large amount of time passes before restoration, brain damage can be permanent.read more >>