Title: Safer Intubation with a nasal cannula? Introducing Apneic Oxygenation
题目：应用鼻导管辅助气管插管安全吗？介绍窒息性供氧
Author 作者: Haney Mallemat

Pre-oxygenation prior to rapid sequence intubation (RSI) is performed to prevent hypoxemia during endotracheal intubation.
快序插管（RSI）前给氧是用来防止由于气管插管时造成的缺氧状态。
An appropriate period of pre-oxygenation will potentially increase the amount of apnea time during intubation, however patients with certain critical illnesses (e.g., severe pneumonia) may desaturate faster than expected.
适当的插管前给氧会增加插管时的呼吸停止时间，同时一些危重病人（如重型肺炎）会很快进入缺氧状态。
Apnea time can be increased by maintaining high-flow oxygen by nasal cannula (e.g., 15L), during application of the bag-valve mask and during the time of attempted endotracheal tube placement; this concept is known as apneic oxygenation.
鼻导管高流量（15升）给氧会增加球囊活门面罩和气管内插管所需的呼吸停止时间，这一概念被称为窒息性供氧。
Apneic oxygenation is based on the principle that when patients are apneic, alveoli absorb oxygen into the blood stream at a rate of approximately 250 mL/minute, creating a diffusion gradient from the pharynx (containing a high-density of oxygen from the nasal cannula) to a lower concentration of oxygen in the alveoli.
窒息性供氧的机制是，在窒息的时候，肺泡氧吸收速度大概为每分钟250毫升，从而在高氧浓度的喉咽部与低氧的肺泡之间产生了氧浓度差，导致氧弥散。
Although a patient’s oxygenation can be maintained longer using apneic oxygenation, its application does not remove the continuous buildup of CO2 in the alveoli during apena. Therefore, respiratory acidosis can result after a prolonged period of apneic oxygenation. 
虽然窒息性供氧会维持较长的氧含量，但并不能排除由于窒息造成的二氧化碳的滞留。因此，长时间的窒息性给氧会产生呼吸性酸中毒。
The complete article describing the physiology and practical applications can be found here....it's free! 这是免费的文章地址： http://www.annemergmed.com/article/S0196-0644(11)01667-2/fulltext
References 参考文献：
Weingart, S and Levitan, R. Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012 Mar; 59(3):165-175.e1