Cardiac and vascular findings using ultrasound in hypovolemic children.

BACKGROUND

Ultrasound is a non-invasive tool that helps assess volume status.

OBJECTIVES

To assess the dehydration and passive leg raising impact on ultrasound-derived cardiac and inferior vena cava parameters to improve early detection of hypovolemia in children.

DESIGN

Prospective observational study in a tertiary paediatric intensive care unit.

METHODS

We recruited 66 healthy children 8-14 years old who fasted in Ramadan. Inferior vena cava diameter, inferior vena cava collapsibility, velocity time integral and maximum velocity (Vmax) were measured at left ventricle outflow tract pre- and post-fasting, with and without passive leg raising. Aorta diameter in systole was also measured pre- and post-fasting.

OUTCOME MEASURES

Inferior vena cava diameter and collapsibility, velocity time integral and Vmax with and without passive leg raising, pre and post fasting, and inferior vena cava/Ao ratio pre and post fasting were measured.

RESULTS

Median percentage of weight loss after fasting was 1.1% (range, 0%-3.9%). Inferior vena cava maximum diameter and inferior vena cava/aorta did not change significantly after fasting ( < 0.05). Inferior vena cava diameters increased and inferior vena cava collapsibility decreased after passive leg raising ( < 0.001) pre and post fasting. Velocity time integral increased with passive leg raising ( < 0.001) but was not affected by fasting ( = 0.17). Vmax increased with passive leg raising and decreased in fasting ( = 0.001).

CONCLUSION

Passive leg raising affected ultrasound measurements. Left ventricle outflow tract Vmax was affected by fasting/mild dehydration, and further trials are needed to confirm its value in predicting hypovolemia in children.

LIMITATIONS

There was no significant effect of dehydration on the measurements probably because of the small sample and mild dehydration. This cannot be generalised because it is a single-centre study and younger children were not included.