# Bilateral Transcranial Doppler Monitoring During Neonatal Cardiac Surgery; Guidance for Clinical and Scientific Use

## TL;DR

This study shows that using bilateral transcranial Doppler monitoring during neonatal heart surgery is feasible and can provide real-time data on brain blood flow.

## Contribution

The study demonstrates the feasibility of continuous bilateral transcranial Doppler monitoring in neonatal cardiac surgery.

## Key findings

- Bilateral transcranial Doppler monitoring was successfully applied in 44 neonatal cardiac surgery procedures.
- Cerebral blood flow velocity measurements showed consistent patterns pre-, during, and post-bypass.
- Signal quality remained sufficient in most cases, with minimal signal deterioration observed.

## Abstract

Neonates undergoing cardiac surgery face a high risk of neurological injury and neurodevelopmental complications. Transcranial Doppler monitoring is used and validated in adults to measure cerebral blood flow and can provide valuable insights into cerebral perfusion in neonates. Nevertheless, it has not been widely introduced in neonatal cardiac surgery.

This study aims to evaluate the feasibility of continuous bilateral transcranial Doppler monitoring for assessing cerebral perfusion during neonatal cardiac surgery.

Continuous transcranial Doppler monitoring was employed during neonatal cardiac surgery with a commercially available transcranial Doppler system and fixation materials. Cerebral blood flow velocity, invasive arterial blood pressure, and other key physiological parameters were measured throughout the procedures.

A total of 44 procedures were monitored. Four were excluded due to storage problems (n = 2), inadequate time to apply the probes (n = 1), and subject drop‐out due to lower surgery severity (n = 1). Bilateral sufficient signal quality was obtained in all patients at the start. Unilateral signal deterioration occurred in 1 (2.5%) of left middle cerebral artery measurements and in 3 (7.5%) of right middle cerebral artery measurements. Mean (SD) left/right MCA CBFV were: pre‐bypass 17.2 (6.4)/15.4 (6.8) cm/s, during bypass 10.8 (4.0)/10.2 (4.3) cm/s, and post‐bypass 18.4 (5.9)/16.1 (5.1) cm/s. Mean (SD) ABP was 38.1 (4.4) mmHg pre‐bypass, 38.0 (5.1) mmHg during bypass, and 47.8 (4.7) mmHg post‐bypass.

This study demonstrates that bilateral transcranial Doppler monitoring is feasible during neonatal cardiac surgery when performed within the recommended operational safety limits. Transcranial Doppler provides real‐time information on cerebral blood flow, complementing existing tools.

ClinicalTrials.gov identifier: NCT04713605