UMEM Educational Pearls

Assessing Volume Status in the Critically Ill

  • In previous pearls we have discussed the many limitations of central venous pressure as an accurate marker of volume status.
  • Importantly, the focus of volume assessment should be on determining which patients are likely to augment their cardiac output in response to additional IVFs, i.e. 'preload responsive'.
  • Ultrasound can be used in the ED to assist in identifying which patients are preload responsive.
  • In general, a 15% variation in the inferior vena cava diameter with respiration predicts response to additional fluids.


Boyd JH, Walley KR. The role of echocardiography in hemodynamic monitoring. Curr Opin Crit Care 2009;15:1-5.