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Perinatal asphyxia, neonatal asphyxia, or birth asphyxia is the medical condition resulting from deprivation of oxygen to a newborn infant that lasts long enough during the birth process to cause physical harm, usually to the brain. Hypoxic damage can occur to most of the infant's organs (heart, lungs, liver, gut, kidneys), but brain damage is of most concern and perhaps the least likely to quickly or completely heal. In more pronounced cases, an infant will survive, but with damage to the brain manifested as either mental, such as developmental delay or intellectual disability, or physical, such as spasticity. It results most commonly from a drop in maternal blood pressure or some other substantial interference with blood flow to the infant's brain during delivery. This can occur due to inadequate circulation or perfusion, impaired respiratory effort, or inadequate ventilation. Perinatal asphyxia happens in 2 to 10 per 1000 newborns that are born at term, and more for those that are born prematurely. An infant suffering severe perinatal asphyxia usually has poor color (cyanosis), perfusion, responsiveness, muscle tone, and respiratory effort, as reflected in a low 5 minute Apgar score. Extreme degrees of asphyxia can cause cardiac arrest and death. If resuscitation is successful, the infant is usually transferred to a neonatal intensive care unit. There has long been a scientific debate over whether newborn infants with asphyxia 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.〔ILCOR Neonatal Resuscitation Guidelines 2010〕〔(Norwegian paediatrician honoured by University of Athens ), Norway.gr〕 There is considerable controversy over the diagnosis of birth asphyxia due to medicolegal reasons. Because of its lack of precision, the term is eschewed in modern obstetrics. ==Cause== * Inadequate oxygenation of maternal blood due to hypoventilation during anesthesia, heart diseases, pneumonia, respiratory failure * Low maternal blood pressure due to hypotension e.g. compression of vena cava and aorta, excess anaesthesia * Inadequate relaxation of uterus due to excess oxytocin * Premature separation of placenta * Placental insufficiency * Knotting of umbilical cord around the neck of infant 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「perinatal asphyxia」の詳細全文を読む スポンサード リンク
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