Don't know how you are going to "burp" a chest wall, but I usually attempt to have the patient cough, just before securing the occlusive dressing. I would never apply a four sided dressing onto a wound, that has pressure enough to "burp", or entrap gasses.
As rid said, steer clear of a 4 sided occlusive dressing should you want to let air out. You also can try and align the layers of tissue to allow for the passing of air while the patient cough by plasing your palms of your hand around the wound and moving them around a little. If you can get your hands on some Jelonet (Gauze embeded in Vaseline), you can use that to make a semi occlusive dressing.