Medical dressing to treat sucking chest wound

A medical dressing configured to be applied to a chest wound, the dressing comprising:

• a flexible main membrane including a front surface configured to face a chest of a patient and a back surface opposite to the front surface, wherein the flexible main membrane includes an opening;
• an adhesive layer on the front surface of the flexible main membrane wherein the adhesive layer extends entirely around the opening and is offset from the opening by at least one-eighth of an inch;
• a flexible sealing membrane entirely covering the opening of the flexible main membrane and overlapping at least a portion of the flexible main membrane;
• an array of joints sandwiched between the sealing membrane and the flexible main membrane, wherein the array of joints extends around the opening of the flexible main membrane, and
• vent passages sandwiched between the flexible main membrane and the sealing membrane, wherein the vent passages extend between joints in the array of joints and each of the vent passages defines an air passage extending from the opening to an outer edge of the sealing membrane.