Design and Validation of a Recirculating Cooling System for Robotic Cardiac Injection Therapy to Improve Patient Safety and Surgeon Workflow

HeartLander is a miniature mobile robot designed to navigate on the surface of the heart using a crawling motion and is well-suited for delivering myocardial injections. Previous work has incorporated a cooling system to enable delivery of a thermally responsive anti-ventricular remodeling hydrogel to a target injection site. However, the previous setup required the saline coolant to be discharged at the distal end of the system and into the patient's pericardial space, hindering the hydrogel from forming a deposit at the target site, presenting an additional burden to the surgeon's workflow, and increasing the risk to the patient. To prevent this, we redesigned the system to include a return channel for the coolant, which discharges to a reservoir outside the patient. We validated this design with a multiphysics simulation, static water bath tests, and by demonstration of controlled injections in an ovine heart ex vivo at 37°C.