<prompt> In an adult, of total body surface required to be involved in a burn injury to cause shock15202530  <response>: As the size approaches 10-15 of total body surface area TBSA, the loss of intravascular fluid can cause a level of circulatory shock. Fuhermore, once the area increases to 25 of TBSA, the inflammatory reaction causes fluid loss in vessels remote from the burn injury.Ref: Bailey and love 27e pg: 619 