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Oxygen xứng đáng vị trí của nó trong dược điển bất kỳ bởi vì - như hầu như bất kỳ loại thuốc khác - oxy có thể làm rất nhiều tác hại, cũng như rất nhiều tốt. Nó cần phải được sử dụng cẩn thận, sử dụng tất cả phải được ghi chép, và 'liều' được sử dụng ghi lại. | OXYGEN Use Supplemental oxygen is used to correct hypoxia in babies with pulmonary problems especially where this is causing a mismatch between the ventilation and the perfusion of the lung. Pathophysiology Oxygen deserves its place in any pharmacopoeia because - like almost any other drug - oxygen can do a lot of harm as well as a lot of good. It needs to be used with care all use should be documented and the dose used recorded. While lack of oxygen can be damaging the body can manage with blood that is only about 50-60 saturated as long as the quantityof oxygen delivered to the tissues is adequate. Were this not true the fetus would be in substantial trouble before birth as would the brain of the baby with cyanotic heart disease. Cardiac output and tissue perfusion matter more than blood pressure and anaemia can undermine oxygen delivery as much as overt cyanosis. While tissue hypoxia can be damaging it is the combined effect of CO2 accumulation and lack of oxygen asphyxia that is most damaging causing a respiratory carbonic acid as well as a metabolic lactic acid acidosis. Too much oxygen can also be damaging however. Prolonged exposure to more than 60 oxygen can be toxic to the pulmonary epithelium and hyperbaric oxygen can cause convulsions. There is also evidence that a relatively high partial pressure of oxygen in the blood is one of a range of factors that can interfere with the normal growth of blood vessels into the retina at the back of the eye in the last 10 weeks of what should have been intrauterine life. In most cases the retinal changes resolve spontaneously leaving no damage but severe change can lead to permanent cicatricial scarring if it involves more than the outer rim of the retina and this scarring can sometimes progress to retinal detachment and complete blindness. Good controlled trial evidence that excessive oxygen could cause blindness first appeared in 1952 but we still do not know precisely what constitutes excessive oxygen. Even the .
