This study aims to explore the feasibility and scientific validity of carotid-jugular Doppler in evaluating volume tolerance in shock patients (with the VExUS score as an important reference standard), and to conduct an in-depth analysis of the correlation between its monitoring indicators and patient prognosis.The primary endpoint is comparison of the agreement between hands-free carotid-jugular Doppler and the VExUS score in evaluating volume tolerance.The secondary endpoint is correlation between volume tolerance assessed by hands-free carotid-jugular Doppler and the clinical outcomes of shock patients.