Autonomic Nervous System Activity during Refractory Rise in Intracranial Pressure.

• Main Authors: Fedriga, Marta, Czigler, Andras, Nasr, Nathalie, Zeiler, Frederick A, Park, Soojin, Donnelly, Joseph, Papaioannou, Vasilios, Frisvold, Shirin K, Wolf, Stephan, Rasulo, Frank, Sykora, Marek, Smielewski, Peter, Czosnyka, Marek
• Format: Article in Journal/Newspaper
• Language: English
• Published: Mary Ann Liebert Inc 2021
• Subjects: Granger causality; autonomic nervous system; refractory intracranial hypertension; upper breakpoint of ICP; Adult; Aged; Baroreflex; Brain Injuries; Female; Heart Rate; Humans; Intracranial Hypertension; Male; Middle Aged; Retrospective Studies; Tromso; Rif
• Online Access: https://www.repository.cam.ac.uk/handle/1810/318580; https://doi.org/10.17863/CAM.65695

Refractory intracranial hypertension (RIH) is a dramatic increase in intracranial pressure (ICP) that cannot be controlled by treatment. Recent reports suggest that the autonomic nervous system (ANS) activity may be altered during changes in ICP. Our study aimed to assess ANS activity during RIH and the causal relationship between rising in ICP and autonomic activity. We reviewed retrospectively 24 multicenter (Cambridge, Tromso, Berlin) patients in whom RIH developed as a pre-terminal event after acute brain injury (ABI). They were monitored with ICP, arterial blood pressure (ABP), and electrocardiography (ECG) using ICM+ software. Parameters reflecting autonomic activity were computed in time and frequency domain through the measurement of heart rate variability (HRV) and baroreflex sensitivity (BRS). Our results demonstrated that a rise in ICP was associated to a significant rise in HRV and BRS with a higher significance level in the high-frequency HRV (p < 0.001). This increase was followed by a significant decrease in HRV and BRS above the upper-breakpoint of ICP where ICP pulse-amplitude starts to decrease whereas the mean ICP continues to rise. Temporality measured with a Granger test suggests a causal relationship from ICP to ANS. The above results suggest that a rise in ICP interacts with ANS activity, mainly interfacing with the parasympathetic-system. The ANS seems to react to the rise in ICP with a response possibly focused on maintaining the cerebrovascular homeostasis. This happens until the critical threshold of ICP is reached above which the ANS variables collapse, probably because of low perfusion of the brain and the central autonomic network. United States National Institutes of Health (NIH), the National Institute of Neurological Disorders and Stroke (NINDS), the Canadian Institutes for Health Research (CIHR), the Canadian Foundation for Innovation (CFI), the University of Manitoba Centre on Aging, the University of Manitoba VPRI Research Investment Fund (RIF), the University of Manitoba ...