Does respiratory variation of inferior vena cava diameter predict fluid responsiveness in spontaneously ventilating children with sepsis.

OBJECTIVE: The intent of fluid bolus therapy (FBT) is to increase cardiac output and tissue perfusion, yet only 50% of septic children are fluid responsive. We evaluated respiratory variation of inferior vena cava (IVC) diameter as a predictor of fluid responsiveness.

METHODS: A prospective observational study in the ED of The Royal Children's Hospital, Melbourne, Australia. Patients were spontaneously ventilating children treated with FBT for sepsis-induced acute circulatory failure. IVC ultrasound was performed prior to FBT. Trans-thoracic echocardiography was performed prior to, 5 and 60 min after FBT. IVC collapsibility index and stroke distance were calculated by a blinded Paediatric Emergency Physician and blinded Paediatric Cardiologist, respectively.

RESULTS: Thirty-nine fluid boluses were recorded in 33 children, 28/39 (72%) of which met criteria for fluid responsiveness at 5 min, which was sustained in 2/28 (7%) of initial fluid responders at 60 min. Sensitivity and specificity (95% confidence interval) of IVC collapsibility index were 0.44 (0.25-0.65) and 0.33 (0.10-0.65) with an area under the receiver operator characteristics curve (95% confidence interval) of 0.38 (0.23-0.55) at 5 min. Test characteristics 60 min after fluid bolus administration were not meaningful because of the infrequency of sustained fluid responsiveness in this patient group. There was no significant correlation between IVC collapsibility and fluid responsiveness at 5 or 60 min.

CONCLUSIONS: IVC collapsibility has poor test characteristics for predicting fluid responsiveness in spontaneously ventilating children with sepsis.