Inferior Vena Cava/Abdominal Aorta Ratio as a Guide for Fluid Resuscitation

The fluid therapy is crucial in the treatment of critically ill children. Inadequate or excessive fluid resuscitation leads to increased mortality and morbidity, thus necessitating an accurate parameter for predicting fluid responsiveness when conducting fluid resuscitation. The inferior vena cava/abdominal aorta (IVC/Ao) ratio is suggested as a good guide for fluid resuscitation. However, the cutoff value for predicting fluid responsiveness in children has not been established. Is IVC/Ao ratio can be used to predict fluid responsiveness?

The objective was to determine the accuracy and a cutoff value of IVC/Ao in predicting fluid responsiveness. A prospective cross-sectional study was conducted in the emergency room and the pediatric intensive care unit of the tertiary hospital from March to August 2017. We consecutively enrolled all critically ill children aged 1 month to 18 years' old who were hemodynamically unstable (shock). Measurements of IVC/Ao with ultrasound and stroke volume with ultrasound cardiac output monitor were obtained before and after fluid challenge.

Of 167 subjects enrolled in this study, only 58 subjects were included, most of whom were male (58.6%) and ranging in age from 1 to 11 months (32.8%). The mean IVC/Ao ratio before the fluid challenge in the fluid responsive group was 0.70 ± 0.053. The best cutoff of the IVC/Ao ratio is 0.675 with area under the curve 70.8% (95% confidence interval of 54.6%-87%), 75.7% sensitivity, and 61.9% specificity for predicting significant fluid responsiveness.

The measurement of IVC/Ao is an accurate, sensitive, and specific parameter to predict fluid responsiveness. The best cut-off for the IVC/Ao ratio is 0.675.