Velocity Time Integral Guides Fluid Therapy for COPD Patients with Septic Shock:a Clinical Study 
YU Jiangquan,ZHENG Ruiqiang,ZHU Jin,ZHAO Yuan,YANG Penglei
Chinese General Practice . 2021, (23): 2945 -2949 .  DOI: 10.12114/j.issn.1007-9572.2021.01.003