How to change open wound dressings?

Clean dressing chang. Wound dressings have to be changed in a clean environment (hands washed with soap and water or disinfectant) If the dressing got stuck to the wound, using sterile water or saline solution can aid in minimizing pain. Once the dressing has been removed the wound has to be cleaned and dressed again. The dressing should be chosen based on the amount of drainage: Absorptive vs moisture donating.
Depends. Your wound care depends on the wound, the location, the size. Be more specific. Best to ask you doctor.