Give Fluid Challenge
Measure VTI or SV before and immediately after 250ml bolus bolus challenge if clinically indicated. Fluid responsive does not mean they need fluid but that they should respond by increasing cardiac output.
You are probably on the steep portion of the FS curve (above)
Test for Predictors of Fluid Responsiveness
Measure SV or VTI interrogating the LVOT, mitral valve inflow or aortic/carotid flows using PWD or CWD to asses for respiratory variations. Make sure you are scanning as parallel to the flow as possible.
As an example, on the images above, LVOT PWD with minimal variation. On the right there is observable variation.
Do you observe a variation of VTI or peak velocity variations >12%
1. Miller A, Mandeville J. Predicting and measuring fluid responsiveness with echocardiography. Echo Res Pract. 2016;3(2):G1-G12. doi:10.1530/ERP-16-0008
2. Desai N, Garry D. Assessing dynamic fluid-responsiveness using transthoracic echocardiography in intensive care. BJA Education, 18(7):218-226(2018)