Clinical trials

Hemodynamic instability is a common and serious condition in patients undergoing liver transplantation and is associated with increased morbidity and mortality if not promptly recognized and treated. It results from multiple interacting factors, including blood loss, changes in vascular tone, cardiac dysfunction, and complications related to the surgical procedure. Traditional monitoring strategies focus on global hemodynamic variables such as blood pressure and cardiac output. However, these parameters may not accurately reflect tissue perfusion or oxygen delivery at the microcirculatory level. As a result, patients may appear hemodynamically stable while still experiencing inadequate tissue oxygenation. This study aims to evaluate hemodynamic instability using an integrative physiological approach based on the interaction between different components of the cardiovascular system. Specifically, the study will assess four key interfaces: the relationship between the heart and the arterial system, the coherence between macrocirculation and microcirculation, the interaction between venous return and the right atrium, and the coupling between the right ventricle and the pulmonary circulation. The main objective is to identify distinct hemodynamic profiles in patients during the immediate postoperative period following liver transplantation. In addition, the study will evaluate the incidence of tissue hypoxia within the first 24 hours and its association with clinical outcomes, including 30-day evolution. This is a prospective observational study conducted in adult patients admitted to the intensive care unit after liver transplantation who develop hemodynamic instability requiring vasoactive support. During the first 24 hours, multimodal hemodynamic monitoring will be performed, including assessment of cardiac function, vascular tone, venous congestion, pulmonary circulation, and markers of tissue perfusion such as lactate levels and capillary refill time. By integrating these variables, patients will be classified into different hemodynamic profiles according to the predominant underlying mechanism. This approach aims to improve the understanding of cardiovascular dysfunction in this setting and to support more individualized and physiologically guided management strategies.

Mechanical ventilation is essential for managing acute respiratory distress syndrome (ARDS), but it can also cause ventilator-induced lung injury (VILI) due to mechanical forces. VILI results from the interaction between lung structure and mechanical ventilation factors, such as tidal volume, plateau pressure, driving pressure, inspiratory flow, respiratory rate, and PEEP. Intrinsic factors like lung heterogeneity further increase the risk. Elastic power (EP), a key component, is linked to repetitive alveolar stretching and disease progression. Study Objectives: Examine the correlation between elastic power and pulmonary hyperinflation. Compare EP's sensitivity and specificity with other overdistension markers like driving pressure, plateau pressure, upper inflection point, and compliance.

Specific characteristics of the lung, such as its functional capacity, heterogeneity, and recruitment potential, can influence the development of ventilator-induced lung injury even under safe ventilation conditions. Objective: To evaluate the risk of ventilator-induced lung injury at the regional level in patients with acute respiratory distress syndrome ventilated with similar tidal volumes and inspiratory pressures.