Neuroanaesthesia: Overview

Neuromodulation: Technology at the Neural Interface is the preeminent journal in the area of neuromodulation, providing our readership with the state of the art clinical, translational and basic science research in our field and representing the needs of the broad neuromodulation community. For clinicians, engineers, scientists and members of the biotechnology industry alike, Neuromodulation provides timely and rigorously peer reviewed articles on the technology, science and clinical application of devices that interface with the nervous system to treat disease and improve function. Neuromodulation covers an ever expanding field including pain, headache, movement disorders, spasticity, paralysis, psychiatric disorders, epilepsy, sensory deprivation, gastric dysfunction, obesity and incontinence.

Abstract
Brain tumor surgeries are among the most challenging procedures in neurosurgery, necessitating careful anesthetic management to achieve maximal tumor resection while preserving neurological function. Anesthesia affects key physiological parameters, including cerebral blood flow, intracranial pressure, and blood-brain barrier permeability, which are crucial in determining surgical outcomes. This mini-review examines the effects of various anesthetic agents, such as propofol, isoflurane, and sevoflurane, on tumor perfusion and infiltration, highlighting their potential to modulate tumor biology through mechanisms involving immune response, angiogenesis, and molecular pathways. The mini-review identifies critical gaps in the literature, particularly concerning the long-term impacts of anesthetic agents on tumor biology and patient survival, and calls for well-conducted randomized controlled trials to address these issues. Furthermore, it explores innovative strategies, including targeted anesthesia delivery and the integration of genomic and proteomic data, to enhance personalized patient care. By synthesizing current knowledge and identifying areas for future research, this mini-review aims to provide a foundation for optimizing anesthetic protocols in brain tumor surgeries to improve both short- and long-term patient outcomes.

Abstract
Background: Recent studies show that levels of the brain injury biomarkers glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) are elevated postoperatively in infants undergoing surgery for craniosynostosis. The aim of this study was to investigate the relationship between intraoperative hypotension and blood loss on biomarker levels.

Methods: This retrospective study included all consecutive patients undergoing surgery for metopic synostosis at our institution from January 2019 to September 2020 who were included in a previous trial. We extracted data from the medical record on intraoperative blood pressure, heart rate, and intraoperative blood loss. Pre- and postoperative GFAP and NfL levels were measured in stored blood samples. Hypotension was defined as the area under the curve (AUC) of mean arterial blood pressure (MAP) at 4 threshold levels (35, 40, 45, and 50 mm Hg, respectively). This AUC and intraoperative blood loss were used to identify correlations with postoperative changes in baseline GFAP and NfL levels.

Results: A total of 20 patients [age: 190±65 d (mean±SD); and weight: 8.0±1.0 kg] undergoing an open cranial vault procedure for metopic synostosis repair were included. Intraoperative blood loss was 27±11 mL/kg, and we did not identify significant association between plasma NfL or GFAP level and any MAP threshold (NfL AUC40 rs=0.08, AUC45 rs=0.15, AUC50 rs=0.30. GFAP AUC40 rs=-0.17, AUC45 rs=0.01, AUC50 rs=-0.06) or blood loss parameter [NfL rs=0.26, GFAP rs=-0.15].

Conclusion: We did not identify a relationship between MAP, blood loss, and markers of brain injury. Our findings suggest that other factors (eg, mechanical manipulation) may explain the observed elevations in brain injury biomarkers after craniosynostosis surgery. This study is limited by its sample size and further investigation is needed.