Clinical definition of negative pressure drainage: that is, the clinical application of self-contained drainage tubes, rinsing tubes of polyvinyl alcohol foam material to cover or fill all kinds of skin or deep tissue wounds, translucent membrane adhesive seal, and then connected to the negative pressure source and rinsing tubes to form a set of complete closed-circuit circulatory system. The system is used to seal, cover and rinse the wound, add medication, oxygen, suction, drainage and other treatments to the wound. This definition is from Weitong Negative Pressure Drainage (Guangzhou Fukang Medical Instrument Co., Ltd)