Theoretical And Applicational Study On Cardiac And Cerebral Hemodynamics In Simulated Acute Hypovolemia

The lower body negative pressure (LBNP) was used as a model of acute hypovolemia. The effects of this simulated acute hypovolemia on cardiac and cerebrovascular hemodynamics were investigated by Doppler ultrasonography, and the effects of generalized sympathetic activation on cerebral autoregulation was further investigated by studying the characteristics of cerebrovascular heamodynamics in healthy young adults and the effects of cold pressor test (CPT) on cerebrovascular hemodynamics. These series of studies made some experimental bases for exploring sensitive Doppler indices to predict the fluid responsiveness and clarifying the mechanisms of syncope in hypovolemia.Part â…  Study on cardiac hemodynamics in simulated acute hypovolemia Objectives To observe the effects of simulated acute hypovolemia on the blood flow velocities in cardiac valves and superior vena cava(SVC), and to study the value of Doppler blood flow velocities and related indices in predicting the fluid responsiveness.