Doppler images of intra-pulmonary shunt within atelectasis in anesthetized children.

BACKGROUND: Doppler images of pulmonary vessels in pulmonary diseases associated with subpleural consolidations have been described. Color Doppler easily identifies such vessels within consolidations while spectral Doppler analysis allows the differentiation between pulmonary and bronchial arteries. Thus, Doppler helps in diagnosing the nature of consolidations. To our knowledge, Doppler analysis of pulmonary vessels within anesthesia-induced atelectasis has never been described before. The aim of this case series is to demonstrate the ability of lung ultrasound to detect the shunting of blood within atelectatic lung areas in anesthetized children.

FINDINGS: Three anesthetized and mechanically ventilated children were scanned in the supine position using a high-resolution linear probe of 6-12 MHz. Once subpleural consolidations were detected in the most dependent posterior lung regions, the probe was rotated such that its long axis followed the intercostal space. In this oblique position, color Doppler mapping was performed to detect blood flow within the consolidation. Thereafter, pulsed waved spectral Doppler was applied in the previously identified vessels during a short expiratory pause, which prevented interferences from respiratory motion. Different flow patterns were identified which corresponded to both, pulmonary and bronchial vessels. Finally, a lung recruitment maneuver was performed which leads to the complete resolution of the aforementioned consolidation thereby confirming the pathophysiological entity of anesthesia-induced atelectasis.

CONCLUSIONS: Lung ultrasound is a non-invasive imaging tool that not only enables the diagnosis of anesthesia-induced atelectasis in pediatric patients but also analysis of shunting blood within this consolidation.