Method and apparatus for inflating and deflating balloon catheters

A method of providing coolant to a medical device having an expandable element, the method comprising:

• transferring the coolant from a first coolant reservoir to a second coolant reservoir in fluid communication with the first coolant reservoir;
• interrupting fluid communication between the first coolant reservoir and the second coolant reservoir to fluidly isolate the first coolant reservoir from the second coolant reservoir;
• transferring the coolant from the second coolant reservoir to the expandable element to inflate the expandable element to a target pressure;
• uninterrupting fluid communication between the first coolant reservoir and the second coolant reservoir;
• and
• evacuating the coolant from the expandable element with a vacuum source such that a target coolant flow rate is achieved while maintaining a pressure in the expandable element at a level substantially equal to or greater than the target pressure.