Improving Trans-Esophageal Echocardiography: A Miniaturized Cooling System

Abstract

Minimally Invasive Surgery (MIS) for cardiac procedures was adopted in the late 90s as a valid alternative to open-heart surgeries, allowing for a minor operative trauma and a faster post-operative recovery. In the context of MIS, the presence of accurate imaging techniques is of paramount importance, as surgeons operate without a direct view of the surgical site. Nowadays, fluoroscopic and ultrasound (US) images, using a Trans-Esophageal probe, are simultaneously employed. The development of real-time three-dimensional Trans-Esophageal Echocardiography has enabled the execution of various trans-catheter procedures. However, recent studies have highlighted the occurrence of esophageal lesions following TEE-guided cardiac interventions. Specifically, probe insertion without direct visualization and repeated adjustment for optimal instrument guidance, along with prolonged use-induced heating, appear to be the primary causes of complications. The major reason for using a dual imaging technique is that commercial probes automatically switch off once a temperature threshold of approximately 42.5°C is reached; for safety reasons related to potential thermal damage to the internal walls of the esophagus. Based on numerical simulations and experimental results, a miniaturized cooling device for TEE probes is proposed, thus reinforcing the reliability of US images in the intraoperative scenario, as they are completely harmless to both patients and doctors. The proposed system consists of a silicone cap incorporating an internal cooling circuit. It does not interfere with the clinical workflow, effectively maintains the probe within a safe temperature range for the entire duration of a surgical procedure, and does not compromise intraoperative image quality.