too low or too high怎么理解？

The differential diagnosis for oxygen desaturation in any patient should include lack of oxygen delivery, inadequate ventilation, and increased oxygen demand. First and foremost listen to the patient to ensure adequate breath sounds. In this case ensure that there is still an adequate source of oxygen to your ventilator or your inflation bag. Ensure patency of all connections. Check the endotracheal tube patency and look for kinks or plugs. Check the endotracheal tube depth and see if it is too low (mainstem intubation) or too high (inadvertent extubation).

任何患者的氧饱和度降低的鉴别诊断都应包括氧输送不足、通气不足和需氧量增加。首先，也是最重要的，要倾听病人的声音，以确保有足够的呼吸声音。在这种情况下，确保您的呼吸机或充气袋仍有足够的氧气来源。确保所有连接的通畅性。检查气管导管是否通畅，检查是否有扭结或堵塞。检查气管插管深度，看是否过低(插管主干)或过高(意外拔管)。

这里的 too low (mainstem intubation) or too high (inadvertent extubation)怎么理解？