Feasibility of Measuring Renal Blood Flow Using Transesophageal Echocardiography in Pediatric Patients Undergoing Cardiac Surgery

Objective

To evaluate the feasibility of measuring renal blood flow (RBF) using transesophageal echocardiography (TEE) in pediatric patients undergoing cardiac surgery.

Design

A prospective noninterventional study.

Setting

A university hospital.

Participants

Twenty-three pediatric patients who underwent surgical repair for complex congenital heart defects were included in this study.

Intervention

None.

Measurements and Main Results

The authors evaluated the accuracy of using TEE to visualize the left renal artery by comparing TEE images with preoperative computed tomography angiographic images. RBF was measured during the cardiopulmonary bypass (CPB) period. TEE images and Doppler studies from all subjects were interpreted by 2 blinded independent assessors. Inter- and intraobserver reproducibility was quantified by calculating the variability and intraclass correlation coefficients. Linear regression models were used to further investigate the relationship between volumetric RBF and CPB perfusion rate. The left renal artery was indentified successfully in 96% of the study population, with a mean Doppler angle of 19.5° ± 6.7° (all of them <30°). Both inter- and intraobserver variability was <10%. Inter- and intraobserver reproducibility in the RBF measurements were excellent. The volumetric RBF showed a linear relationship with the CPB perfusion rate (r = 0.881, p < 0.001) and the mean artery pressure (r = 0.457, p = 0.032).

Conclusion

For 96% of pediatric patients undergoing cardiac surgery, it is feasible to measure RBF using intraoperative TEE during CPB. Volumetric RBF was related to the perfusion rate and the mean artery pressure during CPB.

Key Words:  transesophageal echocardiography , renal blood flow , pediatric patient , cardiac surgery