The role of noninvasive ultrasound blood flow velocity time integral in the evaluation of fluid responsiveness during passive leg raising test

Objective To evaluate the feasibility of using noninvasive ultrasonic cardiac output monitor USCOM velocity time integral (VTI) as the observation index of PLR. Methods This prospective study recruited 36 septic shock or acute pancreatitis patients from October 2014 to October 2016 in the resuscitation room and EICU of Peking Union Medical College Hospital. The change of VTI and plus pressure before and after PLR (ΔVTIplr and ΔPP), and the change of VTI and stroke volume before and after 500 mL of volume expansion (ΔVTIve and ΔSV) were recorded. Fluid response positive was defined as stroke volume increase more than 15% after volume expansion. Results ΔVTIplr was positively correlated with ΔSV (Spearman correlation coefficient r=0.888, P 15% was 94.7%, the specificity was 94.1%, area under the ROC curve was 0.989; the sensitivity of Δ VTIplr in >12% was 84.2%, the specificity was 88.2%, area under the ROC curve was 0.916; and the sensitivity of Δ PP in >10.5% was 78.9%, the specificity was 88.2%, the area under the ROC curve was 0.870. Conclusions Δ VTIplr measured by USCOM before and after the PLR is a sensitive and specific index. It is better than the classic index Δ PP. Δ VTIplr measured by USCOM is completely noninvasive, which has very good application prospect in the emergency department.