Ultrasound can tell you if a child is dehydrated

Using ultrasound at the patient's bedside is a noninvasive way to diagnose intravascular volume depletion in children with gastroenteritis, says a new study.1

Researchers looked at 36 children between 6 months and 16 years with clinical evidence of dehydration. Bedside ultrasound measurements of the inferior vena cava and aorta were taken before and immediately after intravenous (IV) fluids were administered, and these levels were compared to a group of 36 children who did not undergo ultrasound.

As measured by bedside ultrasound, the inferior vena cava and aorta ratio was lower in children clinically assessed to be dehydrated. The level increases with administration of IV fluid boluses, say the researchers.

Because ultrasound is rapid and noninvasive, it can help improve patient flow and cause less pain than using standard laboratory tests to evaluate dehydration, says Lei Chen, MD, the study's author and faculty at Yale University School of Medicine in New Haven, CT.

Although ED physicians perform the ultrasounds, ED nurses could be trained to do them, says Chen. "We have trained nurses to perform bladder ultrasounds prior to urethral catheterizations in young children," she says.2 "We foresee similar possibilities for this modality in the future."


  1. Chen L, Kim Y, Santucci KA. Use of ultrasound measurement of the inferior vena cava diameter as an objective tool in the assessment of children with clinical dehydration. Acad Emerg Med 2007; 14:841-845.
  2. Chen L, Hsiao AL, Moore CL, et al. Utility of bedside bladder ultrasound prior to urethral catheterization in young children. Pediatrics 2005; 115:108-111.