Measurement of intravascular volume status in infants undergoing cranial vault reconstruction for craniosynostosis

Determining the need, optimal timing, amount, and type of fluid for volume expansion in hypovolemic infants is challenging, due to their small intravascular volumes and robust compensatory reserve. To assess markers of fluid responsiveness in hypovolemic infants, we studied those undergoing cranial vault reconstructive surgery-a procedure associated with significant blood loss. We aimed to determine the ability of the Compensatory Reserve Index (CRI) monitor, which provides a continuous, individual-specific, beat-to-beat estimate of central volume status, to distinguish fluid responders from non-responders.

A prospective observational pilot study of infants undergoing cranial vault reconstructive surgery for craniosynostosis was performed from May 2019-January 2020. A CardioQ-Esophageal Doppler Monitor, which measures changes in peak aortic velocity, was utilized to distinguish fluid responders- defined as those who demonstrated an increase in peak aortic velocity > 15% following a crystalloid bolus (10 mL/kg). Several static and dynamic variables were analyzed, including the CRI monitor. Each variable's performance was compared using area under the receiver operator curves (AUC), adjusting for age and bolus volume.

Twenty subjects were included and a total of 23 boluses (19 crystalloid and 4 blood) were administered. Of all boluses, 7 (all crystalloid) were provided to fluid responders and 16 to non-responders. There were no statistically significant differences in bolus volumes or bolus durations between responders and non-responders. While adjusting for age and bolus volume, CRI performed similarly to other bedside tools to predict fluid responsiveness with an AUC of 0.7024 (95% CI = 0.459, 0.946).

Distinguishing infants who are fluid responders from those who are not can be challenging. CRI is a continuous, non-invasive measure that was developed using adult waveform data, yet even in very young patients is able to identify those who may benefit from additional volume expansion.

Therapeutic/Care management.

Level II.