University of Twente Student Theses


Cerebral Autoregulation Monitoring with Transcranial Doppler during Neonatal Cardiac Durgery

Martherus, Boyd Victor (2024) Cerebral Autoregulation Monitoring with Transcranial Doppler during Neonatal Cardiac Durgery.

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Abstract:Neonates with critical congenital heart disease require life-saving cardiac surgery shortly after birth. While survival rates have improved, the challenge of improving neurological outcome, remains urgent. Evidence-based blood pressure and circulatory management strategies in congenital heart disease patients are desirable. Cerebral autoregulation monitoring offers a promising avenue for individualized blood pressure management in this vulnerable population. The objective was to evaluate the feasibility of cerebral autoregulation monitoring for blood pressure management in neonatal cardiac surgery and to investigate its clinical relevance related to neurological outcome. Cerebral autoregulation was monitored in 28 neonates during cardiac surgery with cardiopulmonary bypass between April 2022 and October 2023. Autoregulation monitoring was conducted using transcranial Doppler to measure cerebral blood flow velocity concur- rently with invasive arterial blood pressure monitoring. These measurements were utilized to calculate the mean velocity index, which was determined based on their correlation with each other. A threshold value of the mean velocity index of 0.45 is used to distinguish intact from impaired autoregulation. The mean velocity index is used to determine each individuals optimal blood pressure and limits of autoregulation. The clinical relevance was assessed by examining the association with new white matter injury, as identified through pre- and post- operative MRI scans. Additionally, for comparative purposes, we also employed near-infrared spectroscopy, the modality most commonly reported in the literature for autoregulation monitoring, despite its inherent limitations. Mean gestational age was 38.5 ± 1.0 weeks, and all patients received cardiac surgery within 16 days of life. Cerebral autoregulation monitoring with Transcranial doppler was superior to near infrared spectroscopy. The lower limit of autoregulation was 29.4 ± 6.4 mmHg (range: 19.0 - 41.5), optimal mean arterial blood pressure was 42.0 ± 7.0 mmHg (range: 34.4 - 56.2), and the upper limit of autoregulation was 49.5 ± 4.9 mmHg (range: 44.3 - 58.4). No significant association between patient characteristics and the ability to delineate the cerebral autoregulation curve was found. Additionally, the time spent outside the range for intact autoregulation was not significantly associated with new white matter injury. The study established the feasibility of using Transcranial Doppler for personalized blood pressure management in neonatal cardiac surgery, highlighting significant individual variations in blood pressure thresholds. However, it found no significant link between autoregulation limits during surgery and brain lesion size. Despite its limitations, the study paves the way for future research to refine blood pressure management strategies and improve outcomes in neonatal cardiac care.
Item Type:Essay (Master)
Wilhelmina Children's Hospital, Utrecht, The Netherlands
Faculty:ET: Engineering Technology
Subject:44 medicine
Programme:Technical Medicine MSc (60033)
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