Mechanical cardiopulmonary resuscitation device with telescoping piston

A mechanical cardiopulmonary resuscitation (CPR) device, comprising:

• a central housing;
• a telescoping piston, extending from the central housing, the telescoping piston including:
• an outer piston sleeve structured to move toward and away from the patient's torso and toward and away from the central housing, the outer piston sleeve having a proximal end toward the central housing, the proximal end of the outer piston sleeve configured to remain within the central housing when the telescoping piston is extending from the central housing, and
• an inner piston sleeve within the outer piston sleeve structured to move relative to the outer piston sleeve toward and away from the patient's torso, the inner piston sleeve having a proximal end toward the central housing, the proximal end of the inner piston sleeve configured extend beyond the central housing when the telescoping piston is extending from the central housing;
• and
• a driving component configured to drive the telescoping piston to extend toward the patient's torso and retract the telescoping piston from the patient's torso.