Negative pressure wound therapy (NPWT) is a technique using vacuum dressing to promote wound healing in complicated wound. However for many patients, the application and removal of the NPWT is source of procedural pain. Some techniques had been reported to reduce these pain such as administering topical lidocain or normal saline solution before the dressing change. The authors hypothesized that administering cold water into the NPWT sponge would decrease pain during dressing changes.