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Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry
Published on: January 19, 2020
Cerebral Autoregulation During Antegrade Cerebral Perfusion in Neonates Undergoing Congenital Cardiac Surgery
Zhe Amy Fang1, Bradley S Marino2, Ken M Brady3
1Department of Pediatric Anesthesiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, IL.
Objectives:
Antegrade cerebral perfusion (ACP) is used to protect the brain during aortic arch reconstructions. It is unknown whether cerebral autoregulation remains intact during ACP. This study was designed to determine whether neonates exhibit cerebral vasoreactivity during ACP.
Design:
Retrospective cohort study.
Setting:
Single-center, university hospital.
Patients:
Neonates undergoing aortic arch reconstruction with ACP between August 2021 and January 2025.
Interventions:
Observational study.
Measurements And Main Results:
Demographics, procedural data, and physiological waveform data were collected. The primary outcome was the Hemoglobin Volume Index (HVx), calculated as the moving Pearson correlation coefficient between mean arterial blood pressure (ABP) and regional total hemoglobin (THb). THb is derived from near-infrared reflectance spectroscopy using the isosbestic point for hemoglobin. Below the lower limit of autoregulation (LLA), THb and mean ABP will positively correlate. Cerebral autoregulation curves were constructed for each patient to determine the LLA using an HVx cutoff of ≥0.2. A total of 59 cases involving 58 unique patients were included. The median age was 5 days (interquartile range [IQR] 3, 9), ACP time was 61 minutes (IQR 47, 77), and median LLA was 37.3 mmHg (IQR 34.6, 41.1). Seventeen patients (28.8%) demonstrated intact vasoreactivity. Patients who showed intact autoregulation had significantly less hypotension (LLA - ABPACP) during ACP compared with those who did not (5.0 mmHg [IQR -0.5, 7.17] v 8.5mmHg [IQR 4.7, 12.3]; p = 0.022).
Conclusions:
This study demonstrated that a minority of the neonates examined retained the ability to autoregulate during ACP. Hypotension below LLA is associated with impaired autoregulation during ACP.
