Embodiments of the invention provide apparatus, systems and methods for introducing fluids into a body cavity for hypothermic, resuscitative, or other treatment. One embodiment provides an apparatus for introducing fluids into a peritoneal cavity comprising an access device for insertion into subcutaneous tissue, an infusion member and an advancement member. The access device includes a lumen, a proximal end, a tissue penetrating distal end and a stop for controlling the depth of the distal end into tissue. The infusion member includes an infusion lumen, a removal lumen and at least one sensor and is advanceable from a lumen of the access device into the peritoneal cavity. The advancement member is removably positionable in an infusion member lumen and has sufficient column strength to advance the infusion member tip through abdominal wall tissue into the peritoneal cavity. When the advancement member is removed, the infusion member tip is substantially atraumatic.