An occlusive dressing is an air- and water-tight trauma dressing used in first aid. These dressings are generally made with a waxy coating so as to provide a total seal, and as a result do not have the absorbent properties of gauze pads. They are typically used to treat open, or "sucking," chest wounds to alleviate or prevent a tension pneumothorax (serious complications of a collapsed lung). They are also used in conjunction with a moist sterile dressing for intestinal eviceration.
Occlussive dressings come in various forms, including Vaseline Gauze, which sticks to the skin surrounding the wound using vaseline.
If you do not have a commercial occlusive dressing available and suspect that a patient has a "sucking" chest wound (sucking at wound site, respiratory distress, decreased breath sounds on one side of chest), a piece of plastic or the side of a plastic bag can be placed over the wound and taped to the chest on 3 sides, leaving one side open as a "flutter valve" to allow for exhalation. Whether the seal is taped on 3 or 4 sides varies by jurisdiction. Check with your state laws or medical director in EMS services to determine how your area handles occlusive dressings.
They can also be used to enhance the penetration and absorption of topically-applied medications, such as ointments and creams. Furthermore, they may be used in in vivo acute toxicity tests of dermal irritation and sensitisation. The test animal is shaved and the test material is applied to the skin and wrapped in an occlusive material. The skin is then exposed after 23 hours and an assessment for redness and oedema is made. this assessment is repeated 48 hours later.