Transesophageal Echocardiography for Intraoperative Hemodynamic Assessment: A Physiology-Based, Phase-Oriented...

Intraoperative transesophageal echocardiography (TEE) has evolved from a diagnostic adjunct into a real-time tool supporting perioperative decision-making in cardiac surgery. Although the 2025 American Heart Association Scientific Statement and the 2025 American Society of Echocardiography updates on diastolic and right heart function introduce new parameters and severity grading relevant to intraoperative interpretation, an integrated framework linking these advances to perioperative fluid stewardship has been lacking. This review synthesizes contemporary guidelines and pertinent recent evidence into a physiology-based, phase-oriented practical framework for intraoperative TEE assessment in adult cardiac surgery. Preload assessment integrates left ventricular end-diastolic area, left ventricular outflow tract velocity-time integral dynamics, and diastolic indices and explicitly distinguishes fluid responsiveness from fluid tolerance. Afterload interpretation differentiates vascular load, mechanical obstruction, and vasoplegia. Contractility is assessed using ejection fraction and regional wall-motion analysis, with attention to discordance between global longitudinal strain and ejection fraction. Postpericardiotomy and post‒cardiopulmonary bypass physiology require phase-specific reinterpretation. Emerging measures-including left atrial reservoir strain, 3-dimensional right ventricular ejection fraction, tricuspid annular plane systolic excursion/pulmonary artery systolic pressure coupling, and end-systolic elastance-are discussed as adjuncts, though their intraoperative feasibility and validation remain limited. Many thresholds throughout are extrapolated from transthoracic or intensive care populations rather than validated for intraoperative cardiac surgical TEE. Rather than introducing new measurements, this review organizes established TEE findings into a phase-based decision structure. Each finding is linked to a specific management decision within the Resuscitation-Optimization-Stabilization-Evacuation framework, with particular attention to distinguishing fluid tolerance from fluid responsiveness. The proposed framework is conceptual and warrants prospective validation.