How can I tell if the position and depth of tracheal intubation are correct? It is easy to judge according to the “one look, two listen, three touch” recipe. Tracheal intubation is a skill that must be mastered by physicians in anesthesiology, ICU, and emergency medicine, etc. Internal medicine physicians usually go to anesthesiology to learn tracheal intubation during their rotations, and respiratory physicians (especially in units with RICU) should also master this skill. One of the things we should do immediately after intubating a patient is to confirm the position of the endotracheal tube. This includes whether it has entered the trachea (or esophagus) and how deep it has entered the trachea. Determining whether the catheter has entered the trachea (or esophagus): This is an urgent issue. If the catheter mistakenly enters the esophagus undetected, the consequences are predictable, with the possibility of acute gastric dilatation or even gastric perforation or rupture, as well as difficulty in correcting hypoxemia; if it enters the trachea too deeply, so that it penetrates deep into the left (or right) bronchus, resulting in unilateral ventilation; if it enters too superficially, just near the vocal cords, it can easily be dislodged. To ensure that the tracheal tube is indeed inserted into the airway and not accidentally into the esophagus, one of the most important lessons is that we witness the tip of the tube actually going in between the vocal cords, and as long as we keep our eyes on the action, we cannot be mistaken unless we are hallucinating. However, beginners may move their eyes away after exposing the entrance to the vocal cords, when the tracheal intubation catheter is not yet near the vocal cords, and accidental entry into the esophagus can happen. In addition, there are many ways to determine that the tracheal intubation catheter has entered the trachea. First, look: observe the thoracic heave and stomach during ventilation, if the thoracic heave is not obvious after ventilation, and the abdomen is obviously bulging, and there is regurgitated gastric contents in the trachea, there is no doubt that the catheter has entered the esophagus by mistake. If the ventilator is connected and the flow waveform of the exhaled air can be seen and the waveform is good, it is in the trachea. If you can monitor the patient’s end-expiratory carbon dioxide, if inserted into the trachea, you can see the square wave of carbon dioxide during expiration. It is generally believed that end-expiratory carbon dioxide monitoring is the most accurate, while expiratory waveform monitoring is simpler and more accurate. Second, listen: listen to the chest and abdominal breath sounds during ventilation, if the chest breath sounds are strong and the upper abdomen is not obvious, the tracheal tube is considered to be located in the trachea. If the catheter is in the stomach, we may also hear a very loud sound in the chest bilaterally during ventilation, but this is still different from the breath sounds and should be distinguished. Not that we hear the sound in the bilateral lungs to conclude that the catheter in the trachea, not also Third, touch, listen: after intubation, squeeze the thorax, if you hear breathing sounds at the mouth of the tracheal tube, the airflow is obvious more suggestive of the trachea. Note that this is only said to be “more likely”, not absolute. When judging the position of the catheter, we must pay attention to the monitoring of vital signs, and if the decision is unclear or the vital signs become poor, we should decisively remove the catheter, buckle the mask, pinch the skin ball, and reintubate after full oxygenation, and if necessary, we can ask a master to help. Judgment of how deep into the trachea: The above is to judge whether the catheter is in the trachea after intubation, and at the same time we have to judge how deep the catheter is inserted into the trachea, which is also very important. See below: The distance between the adult male incisors and the voice box is about 15-18 cm (14-16 cm for women), and the distance between the incisors and the rongeur is 25-32 cm (23-30 cm for women). What is the appropriate depth of insertion of the tracheal tube? It is generally accepted that the tip of the catheter should reach the middle of the trachea, i.e. 4-5 cm below the vocal cords, without being too shallow or too deep. The insertion depth is generally considered to be 23-25 cm from the incisors in male patients and 20-22 cm in female patients, with slight adjustments depending on the size of the patient. Pay attention to the symmetry of breath sounds on both sides of the chest with the stethoscope, if it is not symmetrical, it may be inserted too deep, withdraw a little and re-listen. It is best to take a chest radiograph to further adjust the position of the catheter, but clinically it is usually not deliberate to take an emergency bedside chest radiograph to determine the position, unless there are other reasons to take a chest radiograph (such as pneumonia), then the catheter position can be seen in passing.