摘要INTRODUCTIONThe microcirculation is attracting more and more attention due to its central role in prognosis of critically ill patients.Monitoring perfusion of patients on intensive care units is of highest priority to guide diagnostic and treatment strategies to optimize organ perfusion,subsequently leading to an individualized therapy.The most often used parameter to detect alterations in the microcirculation is serum lactate;there is still lack of bedside monitoring methods for direct observation of microcirculation.With the noninvasive,convenient,and unique value in the quick diagnosis and dynamic monitoring during the course of treatment,bedside critical ultrasonography has been widely used,regarded as the "visual stethoscope." Contrast-enhanced ultrasonography (CEUS) is a competing technology that enables real-time observation of vascular perfusion;the basic composition of the contrast agents is microbubbles made of gases embedded within a shell characterized by safety,high tolerance,and lack of radiation,which can reflect ultrasound and avoid destruction during circulation and allow for continuous imaging of the vasculature and microcirculation.Therefore,CEUS can be used for the assess tissue microcirculation of critically ill patients,particularly in visceral organs.[1]