Subhi Rami, Smith Katherine, Duke Trevor
Centre for International Child Health, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Victoria, Australia.
Arch Dis Child. 2009 Jan;94(1):6-10. doi: 10.1136/adc.2008.138362. Epub 2008 Oct 1.
Acute respiratory infections (ARI) cause 3 million deaths in children worldwide each year. Most of these deaths occur from pneumonia in developing countries, and hypoxaemia is the most common fatal complication. Simple and adaptable indications for oxygen therapy are important in the management of ARI. The current WHO definition of hypoxaemia as any arterial oxygen saturation (SpO(2)) <90% does not take into account the variation in normal oxygen saturation with altitude. This study aimed to define normal oxygen saturation and to estimate the threshold of hypoxaemia for children permanently living at different altitudes.
We carried out a systematic review of the literature addressing normal values of oxygen saturation in children aged 1 week to 12 years. Hypoxaemia was defined as any SpO(2) at or below the 2.5th centile for a population of healthy children at a given altitude. Meta-regression analysis was performed to estimate the change in mean SpO(2) and the hypoxaemia threshold with increasing altitude.
14 studies were reviewed and analysed to produce prediction equations for estimating the expected mean SpO(2) in normal children, and the threshold SpO(2) indicating hypoxaemia at various altitudes. An SpO(2) of 90% is the 2.5th centile for a population of healthy children living at an altitude of approximately 2500 m above sea level. This decreases to 85% at an altitude of approximately 3200 m.
For health facilities at very high altitudes, giving oxygen to all children with an SpO(2) <90% may be too liberal if oxygen supplies are limited. In such settings, Spo(2) <85% may be more appropriate to identify children most in need of oxygen supplementation.
急性呼吸道感染（ARI）每年在全球导致300万儿童死亡。这些死亡大多发生在发展中国家的肺炎病例中，而低氧血症是最常见的致命并发症。简单且适用的氧疗指征在ARI的管理中很重要。世界卫生组织目前将低氧血症定义为任何动脉血氧饱和度（SpO₂）<90%，但未考虑到正常血氧饱和度随海拔高度的变化。本研究旨在确定正常血氧饱和度，并估计长期生活在不同海拔高度儿童的低氧血症阈值。
我们对关于1周龄至12岁儿童血氧饱和度正常值的文献进行了系统综述。低氧血症被定义为在给定海拔高度的健康儿童群体中，任何SpO₂处于或低于第2.5百分位数。进行了元回归分析以估计平均SpO₂的变化以及低氧血症阈值随海拔升高的变化。
对14项研究进行了综述和分析，以得出用于估计正常儿童预期平均SpO₂以及指示不同海拔高度低氧血症的SpO₂阈值的预测方程。对于生活在海拔约2500米的健康儿童群体，SpO₂为90%是第2.5百分位数。在海拔约3200米时，这一数值降至85%。
对于海拔非常高地区的医疗机构，如果氧气供应有限，对所有SpO₂<90%的儿童给予氧气可能过于宽松。在这种情况下，SpO₂<85%可能更适合用于识别最需要补充氧气的儿童。
