Background: The brain is an organ that has a broad blood perfusion. Many factors such as hypoxia, anaesthesia, stress or the presence of CO2 as well as hydrogen ions within arterial blood, modify cerebral blood flow and tisular perfusion. Objectives: The objective of this review is to analyse the available literature about cerebral blood flow and tisular oxygenation. Methods: A targeted literature review and specific search was carried out aimed at the identification, recovery and bibliographic review of several independent studies that are key in brain physiology and that allow us to better understand cerebral perfusion and oxygenation. Conclusions: Cerebral blood flow is highly dependent on both, internal and external factors. Maintaining adequate cerebral oxygenation is essential to ensure the proper functioning of the brain and maintain neuronal homeostasis. The cerebral blood flow of the brain is on average 45-50 ml/100g/min and the partial pressure of cerebral oxygen (PtO2) ranges between 20 to 30 mmHg under normal conditions.
