Systems, devices, and methods permit insulation of a body cavity prior to the insertion of a cannula into the body cavity. Some embodiments of an access system comprise an obturator (160), a trocar (110), and a fluid flow channel (180). The access system has a closed configuration, in which a distal end of the access system is fluidly isolated from the fluid flow channel, and an open configuration, in which the distal end of the access system is fluidly connected to the fluid flow channel, thereby permitting fluid flow, for example, an insulation gas into a body cavity.
