Calibrated abdominal compression to assess fluid responsiveness in extremely and very preterm neonates: a pilot study

Predicting fluid-responsiveness is challenging in preterm neonates. It is however crucial to avoid unnecessary fluid bolus that could lead to fluid overload. In children, stroke volume changes induced by an abdominal compression (ΔSV-AC) can predict fluid responsiveness. This exploratory pilot study aimed to evaluate the feasibility and tolerance of this preload challenge in preterm neonates.

This prospective, single-center pilot study was conducted in a tertiary neonatal intensive care unit. Mechanically-ventilated and sedated preterm neonates under 32 weeks of corrected gestational age who required a 10 mL.kg^-1 fluid bolus were eligible. Stroke volume was measured by echocardiography at baseline, during a gentle abdominal compression, and after the fluid bolus. A ≥15% stroke volume increase after fluid bolus defined fluid-responsiveness. In exploratory analysis, area under the receiver operating characteristic curve (AUROC) of ΔSV-AC was measured to predict fluid-responsiveness.

Eighteen fluid boluses were analyzed. Fluid-responsiveness was observed in 8 (44%) cases. The calibrated abdominal compression and the echocardiographic measurements were feasible in all cases. Although no serious adverse events were attributed to the maneuver, we observed three cases of transient but significant decreases in stroke volume or heart rate, two of which were accompanied by a subjective impression of poor tolerance. All other cases were subjectively rated as well tolerated. In exploratory analysis, after adjustment for repeated measures, the AUROC of ΔSV-AC to predict fluid-responsiveness was 0.76 (95% CI 0.43-1). The best threshold for ΔSV-AC was 17% with a specificity of 0.91 (95% CI 0.60-1), a sensitivity of 0.51 (95% CI 0.17-1), and positive and negative predictive values of 0.85 (95% CI 0.36-1) and 0.68 (95% CI 0.33-1) respectively.

This study suggests that calibrated abdominal compression could be feasible in a population of critically ill preterm neonates mostly suffering from PPHN-related shock, although its tolerance is uncertain. Further studies are needed to better tailor this maneuver to preterm neonates and to characterize its diagnostic accuracy, including in more common etiologies of neonatal shock.Clinical Trial Registration: https://clinicaltrials.gov/study/NCT06287710, identifier NCT06287710.