During an acute asthma attack, it can be graded according to the severity of the condition, which is divided into four grades: mild, moderate, severe and critical. Mild: Patients usually have shortness of breath after activity, and can lie down or live normally. They can speak in long continuous sentences, are in good spirits and do not sweat significantly, and their respiratory rate increases mildly. Pulmonary function indicators are in the normal range, PEF is above 80% of the expected value, and blood gas analysis are also in the normal range. Moderate: Shortness of breath usually occurs after a little activity, preference for sitting, frequent interruptions in speech, slight anxiety and irritability, sweating, increased respiratory rate, and activity of the supplementary respiratory muscles. The trigeminal sign may be seen, loud and diffuse croup may be heard in both lungs, the heart rate may increase, and there may be a decrease in lung function. Severe: Shortness of breath may be manifested even at rest, and there is telangiectatic breathing, anxiety, and profuse sweating. The heart rate and respiratory rate increase significantly, and the partial pressure of oxygen in blood gas analysis decreases significantly, and respiratory failure is manifested. In severe cases, the patient may show drowsiness, blurred consciousness, inability to speak, and contradictory chest and abdominal movements.