Inspiratory pressure generally refers to the intrathoracic pressure at the end of calm inspiration, and its normal value is -10 to -5 mmHg, beyond which it can be considered abnormal. Under normal circumstances, negative pressure is usually maintained in the chest cavity to allow effective pulmonary ventilation. When a disease such as pneumothorax occurs, the end-inspiratory intrathoracic pressure can increase, and even dyspnea can occur as a result. Therefore, when this test is found to be elevated, or even becomes positive, please seek help from a medical professional in a timely manner. If the patient is accompanied by dyspnea and other uncomfortable symptoms, it is necessary to consult a doctor in time to avoid delaying the condition.