The present invention provides a medical device for manipulation of tissue of a patient. The medical device comprises a shaft having a proximal section extending to a distal section that has a closed distal end portion. The shaft has a plurality of lumens formed therein including a first lumen and a second lumen. The first lumen is for distally advancing a first reactant through the proximal section. The second lumen is for distally advancing a second reactant through the proximal section. Positioned longitudinally within the shaft and distally from the first and second lumens is a mixing element. The mixing element is in fluid communication with the first and second lumens. The mixing element has a series of baffles for mixing the first and second reactants together producing a reaction product to heat the closed distal end portion of the shaft for manipulation of the tissue.
