Safety and Feasibility of Bedside Electrical Impedance Tomography With Hypertonic Saline Contrast for Assessing Pulmonary Perfusion in Mechanically Ventilated Children With Acute Respiratory Distress Syndrome: A Pilot Study.

Abstract

Importance: Electrical impedance tomography (EIT) offers a noninvasive, radiation-free imaging alternative, but its perfusion evaluation capability in children is understudied. Hypertonic saline-enhanced EIT may address this gap, enabling real-time guidance for individualized respiratory support.

Objectives: This study aims to systematically assess the safety and efficacy of hypertonic saline-enhanced bedside EIT in evaluating pulmonary perfusion in pediatric patients with acute respiratory distress syndrome (ARDS).

Design: Single-center prospective observational study.

Setting and participants: Pediatric ARDS patients undergoing invasive mechanical ventilation were enrolled at the PICU of the Capital Center for Children's Health, Capital Medical University, China, from December 29, 2024, to August 7, 2025.

Main outcomes and measures: Each participant received a central venous bolus of 0.2 mL/kg (up to a maximum of 10 mL) of a 10% hypertonic saline. EIT data were collected from 2 minutes before the injection to 1-2 minutes following it. Key parameters, including dead space ventilation fraction, intrapulmonary shunt fraction, and ventilation/perfusion (V/Q) matching percentage, were analyzed to evaluate lung pathophysiology and inform therapeutic strategies. The study monitored eight patients (four males, four females; ages ranging from 4 mo to 11 yr).

Results: All procedures were well-tolerated, with no adverse events, including hypernatremia. In five patients who also underwent contrast-enhanced CT, EIT findings were consistent with CT results. Seven patients demonstrated matched V/Q ratios (74.97-80.39%), while one patient with pulmonary embolism exhibited increased dead space ventilation (37.03%) and decreased V/Q matching (60.71%).

Conclusions and relevance: Hypertonic saline-enhanced EIT is a safe, effective, and feasible bedside method for evaluating pulmonary perfusion in mechanically ventilated children with ARDS. These findings implied potential associations with the CT outcomes, indicating its significant potential for guiding targeted respiratory management. Although promising, these results stem from a small sample size, necessitating further validation in larger studies.