Comparison of the Ultrasonic Cardiac Output Monitor and Echocardiography for Hemodynamic Assessment in Pediatric...

To compare the Ultrasonic Cardiac Output Monitor (USCOM) and suprasternal Doppler echocardiography obtained from the same acoustic window in children under general anesthesia, focusing on flow-derived parameters used for perioperative fluid assessment.

Prospective observational study.

Single tertiary-care university hospital operating rooms.

Children aged 6 months to 15 years (American Society of Anesthesiologists physical status I-II) undergoing elective surgery with standardized general anesthesia.

Performance of suprasternal continuous-wave Doppler measurements using USCOM followed immediately by suprasternal Doppler echocardiography under unchanged ventilatory and anesthetic conditions.

After induction and hemodynamic stabilization, stroke volume, velocity time integral, aortic valve area, and stroke volume variation were recorded as the mean of 3 consecutive measurements. Fifty-seven children were included (median age 7 years; interquartile range, 3.4-11 years). USCOM produced higher stroke volume and velocity-time integral values than echocardiography, while aortic valve area estimates were similar. The greatest discrepancy was observed for stroke volume variation, which was markedly higher with USCOM and demonstrated wide limits of agreement. Using a 12% threshold, USCOM classified most patients as fluid responsive, whereas echocardiography identified substantially fewer children above this cutoff.

Even when measurements were obtained from the same suprasternal window under controlled intraoperative conditions, USCOM systematically overestimated flow-derived parameters and markedly inflated stroke volume variation compared with echocardiography. These findings suggest that USCOM-derived stroke volume variation should be interpreted with caution in pediatric anesthesia and should not be used interchangeably with echocardiography to guide perioperative fluid management.