The grading of edema is as follows: I. Edema of both lower limbs can be divided into three levels, i.e. mild edema, moderate edema and severe edema. Mild edema means that edema is limited to below both ankles, moderate edema means that edema is limited to below both knees, and severe edema means that edema exceeds both knees; II. Edema is also divided into three degrees. I degree edema means that the skin will be depressed when pressing, but it recovers quickly, II degree edema means that there is depression after pressing and the depression cannot be recovered within 10 seconds, and the skin does not shine, and III degree edema means that the depression cannot be recovered after pressing for more than 10 seconds, and the skin shines or even flows.