<P> There has long been a debate over whether newborn infants with cerebral hypoxia should be resuscitated with 100% oxygen or normal air . It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia . Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen . </P> <P> Brain damage can occur both during and after oxygen deprivation . During oxygen deprivation, cells die due to an increasing acidity in the brain tissue (acidosis). Additionally, during the period of oxygen deprivation, materials that can easily create free radicals build up . When oxygen enters the tissue these materials interact with oxygen to create high levels of oxidants . Oxidants interfere with the normal brain chemistry and cause further damage (this is known as "reperfusion injury"). </P> <P> Techniques for preventing damage to brain cells are an area of ongoing research . Hypothermia therapy for neonatal encephalopathy is the only evidence - supported therapy, but antioxidant drugs, control of blood glucose levels, and hemodilution (thinning of the blood) coupled with drug - induced hypertension are some treatment techniques currently under investigation . Hyperbaric oxygen therapy is being evaluated with the reduction in total and myocardial creatine phosphokinase levels showing a possible reduction in the overall systemic inflammatory process . </P> <P> In severe cases it is extremely important to act quickly . Brain cells are very sensitive to reduced oxygen levels . Once deprived of oxygen they will begin to die off within five minutes . </P>

When does brain damage occur from lack of oxygen