order啥意思？

In the conscious healthy subject, the shunt or venous admixture amounts to only 1% to 2% of cardiac output (page 101). This results in an alveolar/arterial Po2 gradient of less than 1 kPa (7.5 mmHg) in the young healthy subject breathing air, but the gradient increases with age and lung disease. During anaesthesia, the alveolar/arterial Po2 difference is usually increased to a value that corresponds to an average shunt of about 10%. Measurements of pulmonary venous admixture, taking into account the mixed venous oxygen content, have also been made, and these concur with shunts of the order of 10%. This provides an acceptable basis for predicting arterial Po2 during an uncomplicated anaesthetic, and it also permits calculation of the concentration of oxygen in the inspired gas that will provide an acceptable arterial Po2. About 30% to 40% inspired oxygen is usually adequate in an uncomplicated anaesthetic.

在清醒的健康受试者中，分流或静脉血掺杂仅占心输出量的1%～2%（第101页）。这导致呼吸空气时，年轻健康受试者P（A-a）O2＜1kpa（7.5mmHg），但P（A-a）O2随肺部疾病和年龄的增加而增加。麻醉时，P（A-a）O2通常增加至相当于约10%平均分流的对应值。考虑到还有混合静脉血氧含量，还测量了肺静脉血掺杂，这些结果与10%左右的分流率一致。10%左右的分流率为预测无并发症麻醉期间的PaO2值奠定了一个可行的基础，也允许在为患者提供可接受的PaO2 时根据10%左右的分流率计算出需要的吸入氧浓度，在无并发症的麻醉中，通常约30%～40%的吸入氧浓度就足够了。