Optimizing agitated saline volume for contrast echocardiography: Balancing diagnostic performance and operator fatigue

Abstract

Background

Agitated saline contrast echocardiography, essential for patent foramen ovale detection, typically uses a 10 mL saline protocol, which may lead to operator fatigue and compromise diagnostic accuracy. This study aimed to identify an optimal saline volume that balances diagnostic efficacy and minimizes operator fatigue.

Methods

Fifty-three patients with suspected patent foramen ovale underwent echocardiography using three saline protocols: 10 mL (9 mL saline + 1 mL air), 7 mL (6.4 mL saline + 0.6 mL air), and 5 mL (4.6 mL saline + 0.4 mL air). The protocols were evaluated for their impact on microbubble signal intensity in the right atrium, right-to-left shunt grading, and operator fatigue, as assessed by the Borg CR10 scale.

Results

The signal intensities were comparable between the 10 mL and 7 mL protocols, while the 5 mL protocol showed significantly lower signal intensities at all time points (p < 0.001). The 7 mL protocol achieved 100% right-to-left shunt grading concordance with the 10 mL protocol, while the 5 mL protocol showed decreased accuracy and recall. Operator fatigue significantly decreased with the reduction in saline volume (p < 0.001), and the 7 mL protocol demonstrated optimal diagnostic accuracy and reduced fatigue.

Conclusion

A 7 mL agitated saline volume is recommended for contrast echocardiography to maintain diagnostic accuracy while significantly reducing operator fatigue, offering a practical balance between diagnostic precision and operator comfort.