Abstract: A surgical instrument for providing an ionized gas to a surgical site includes a receptacle for a cylinder of pressurized surgical gas and a frame having a port near the distal end for emitting the surgical gas. A passageway extending between the receptacle and the port delivers the surgical gas to an electrode that is adapted for connection to a source of electrosurgical energy. A puncture assembly for rupturing a seal on the cylinder to release the surgical gas into the passageway includes a spring movable between a first state for storing mechanical energy and a relaxed state. An actuator is operable to move the spring to the relaxed state. A puncture pin is operatively coupled to the spring such that energy released by movement of the spring to the relaxed state is effective to move the puncture pin relative to the cylinder to rupture the seal.