For which three degrees of pneumothorax leakage, it is mainly given to the clinician’s judgment after intubation, which are mild, moderate and severe. If there are no air bubbles coming out of the water seal bottle when the patient is breathing calmly and deeply, but only when the patient coughs hard, it is a mild air leak. If there is no air leakage when the patient is breathing calmly, but bubbles come out when the patient is breathing deeply and coughing, it is a moderate air leakage. There are also severe air leaks, where the patient has air leaks when breathing calmly and even more when breathing deeply and coughing.