Systems, assemblies, and methods for treating a bronchial tree

A catheter (2000, 2500, 3000), comprising: an elongated body (2030, 2530) through which a coolant can flow; an electrode (2004, 2504) configured to deliver energy to ablate nerve tissue in an airway wall of a bronchial tree; and an expandable balloon (2002, 2502, 3002) having a collapsed state and an expanded state, wherein the expandable balloon in the expanded state is sized to contact the airway wall of the bronchial tree, wherein the expandable balloon engages the elongate body and is configured to contain the coolant such that the coolant cools the electrode and the expandable balloon when the catheter is in contact with the airway wall to limit or prevent tissue damage between the electrode and the nervous tissue, where the electrode (2004) is attached to the expandable balloon (2002, 2502, 3002) such that electrode (2004) is moved toward the airway wall as the expandable balloon moves from the collapsed state to the expanded state, and wherein electrode (2004) is configured to deliver a sufficient amount of energy to ablate a portion of a nerve trunk that runs along the bronchial tree to attenuate nervous system signals transmitted to a portion of the bronchial tree while the expandable balloon (2002, 2502, 3002) is in the expanded state, and wherein the expandable balloon (2002, 2502, 3002) is configured to absorb thermal energy from the airway wall to limit or prevent tissue damage between the electrode and nerve tissue, wherein the elongated body includes an internal inflow passage (2011) that is coupled to a coolant inlet (2013) close to one end of the expandable balloon characterized in that the elongated body further includes an internal outlet passage (2021) that is coupled to a coolant outlet (2023) at another end of the expandable balloon such that coolant circulates within the expandable balloon as the coolant flows through the internal inflow passage, the coolant inlet, the coolant outlet and the internal outlet passage.