You can do neck surgery to see the trachea and then intubate the trachea where you can see the tube from neck.You are ery sure whether the tube is into the chachea by this way.

• 我们有一个办法；就将老鼠麻醉后；平放；用冷光源的灯直接照在喉部皮肤上；距离非常近；将灯头贴在皮肤上；然后将老鼠舌头拉出；在灯光照射下可以看到气管开口的鱼口状；然后将管插入即可.