Increased Intracranial Pressure Attenuates the Pulsating Component of Cerebral Venous Outflow

Unnerbäck, Mårten; Ottesen, Johnny T.; Reinstrup, Peter

doi:10.1007/s12028-019-00733-4

Cited by 13 publications

(13 citation statements)

References 30 publications

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“…While this effect is most easily observed in sheep F, it can also be observed in all sheep where ITP to ICP communication existed. Minimal CVP reaction was observed across the infusion study both in mean and pulse, corresponding to previous literature stating that elevated ICP serves to attenuate venous pulse reactions [ 29 ].…”

Section: Discussionsupporting

confidence: 76%

Intercompartmental communication between the cerebrospinal and adjacent spaces during intrathecal infusions in an acute ovine in-vivo model

Podgoršak

Trimmel

Oertel

et al. 2022

Fluids Barriers CNS

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Introduction The treatment of hydrocephalus has been a topic of intense research ever since the first clinically successful use of a valved cerebrospinal fluid shunt 72 years ago. While ample studies elucidating different phenomena impacting this treatment exist, there are still gaps to be filled. Specifically, how intracranial, intrathecal, arterial, and venous pressures react and communicate with each other simultaneously. Methods An in-vivo sheep trial (n = 6) was conducted to evaluate and quantify the communication existing within the cranio-spinal, arterial, and venous systems (1 kHz sampling frequency). Standardized intrathecal infusion testing was performed using an automated infusion apparatus, including bolus and constant pressure infusions. Bolus infusions entailed six lumbar intrathecal infusions of 2 mL Ringer’s solution. Constant pressure infusions were comprised of six regulated pressure steps of 3.75 mmHg for periods of 7 min each. Mean pressure reactions, pulse amplitude reactions, and outflow resistance were calculated. Results All sheep showed intracranial pressure reactions to acute increases of intrathecal pressure, with four of six sheep showing clear cranio-spinal communication. During bolus infusions, the increases of mean pressure for intrathecal, intracranial, arterial, and venous pressure were 16.6 ± 0.9, 15.4 ± 0.8, 3.9 ± 0.8, and 0.1 ± 0.2 mmHg with corresponding pulse amplitude increases of 2.4 ± 0.3, 1.3 ± 0.3, 1.3 ± 0.3, and 0.2 ± 0.1 mmHg, respectively. During constant pressure infusions, mean increases from baseline were 14.6 ± 3.8, 15.5 ± 4.2, 4.2 ± 8.2, and 3.2 ± 2.4 mmHg with the corresponding pulse amplitude increases of 2.5 ± 3.6, 2.5 ± 3.0, 7.7 ± 4.3, and 0.7 ± 2.0 mmHg for intrathecal, intracranial, arterial, and venous pulse amplitude, respectively. Outflow resistances were calculated as 51.6 ± 7.8 and 77.8 ± 14.5 mmHg/mL/min for the bolus and constant pressure infusion methods, respectively—showing deviations between the two estimation methods. Conclusions Standardized infusion tests with multi-compartmental pressure recordings in sheep have helped capture distinct reactions between the intrathecal, intracranial, arterial, and venous systems. Volumetric pressure changes in the intrathecal space have been shown to propagate to the intraventricular and arterial systems in our sample, and to the venous side in individual cases. These results represent an important step into achieving a more complete quantitative understanding of how an acute rise in intrathecal pressure can propagate and influence other systems.

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Section: Discussionsupporting

confidence: 76%

Intercompartmental communication between the cerebrospinal and adjacent spaces during intrathecal infusions in an acute ovine in-vivo model

Podgoršak

Trimmel

Oertel

et al. 2022

Fluids Barriers CNS

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“…Their results are consistent with the present study. A recent study also reported that increased ICP attenuates the pulsatility of cerebral venous out ow [26] .…”

Section: Interpretation Of the Decreased Pimentioning

confidence: 85%

Phase-Contrast MRI Indices can Reflect Intracranial Compliance Deterioration Induced by Intra-Abdominal/ Thoracic Hypertension

Feng

Liu³

et al. 2021

Preprint

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BackgroundIdentifying elevated intracranial pressure (ICP) and decreased intracranial compliance (ICC) is imperative for optimizing patient management in neurocritical care settings. Intra-abdominal hypertension (IAH) and intrathoracic hypertension (ITH) is common in trauma patients, which affects homeostasis of ICP/ICC. Knowledge of this effects is little and monitoring this effect is difficult. In the current study, we examined whether the indices generated from 2D cine phase contrast MRI (2D cine PC-MRI) could reflect ICC/ICP alterations induced by elevated IAH/ITH during VM.MethodsA total of 50 healthy young volunteers participated in this study (male: female = 24:26), and took a 2D cine PC-MRI during normal breath and VM respectively. Cross-section area (CSA) of dominant IJV and ipsilateral ICA, the maximum blood flow (Fmax), minimum blood flow (Fmin), mean blood flow (MBF), pulsatility index (PI), arteriovenous delay (AVD) and time to peak of arterial pulse (TTP) were gauged from images or calculated from the blood flow curves generated from 2D cine PC-MRI. ResultsDuring VM state, in comparison to NB, CSAIJV increased significantly (p<0.0001), indicating an elevation of cerebral venous outflow resistance; Fmax_ICA, Fmax_IJV, Fmean_ICA and Fmean_IJV decreased significantly (p<0.0001, p<0.0001, p<0.001, p<0.0001, respectively); PI_ICA and PI_IJV decreased significantly (p<0.0001, p<0.0001); both absolute and normalized AVD decreased significantly (p<0.0001, p<0.0001), while absolute and normalized TTP increased significantly (p=0.0329, p=0.0376).Conclusions Indices generated from 2D cine PC-MRI, especially AVD and TTP, can reveal the ICC/ICP dynamics induced by elevated IAP/ITP. These indices have potential clinical application in ICC/ICP monitoring in patients who was speculated with an IAH or ITH.

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“… 61 Not only do these large movement cause significant increase of ICP, small movements, such as twitching and changes in body position, 111 can increase ICP dramatically. It is important to understand the ICP change and its relation with different behaviors, because ICP elevation alters CSF clearance pathways, 163 , 164 affects venous outflow dynamics 165 and determines sympathetic activity. 166 , 167 Increases in ICP are also associated with pathology.…”

Section: Other Physiological Signal Monitoringmentioning

confidence: 99%

Behavioral and physiological monitoring for awake neurovascular coupling experiments: a how-to guide

et al. 2022

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. Significance: Functional brain imaging in awake animal models is a popular and powerful technique that allows the investigation of neurovascular coupling (NVC) under physiological conditions. However, ubiquitous facial and body motions (fidgeting) are prime drivers of spontaneous fluctuations in neural and hemodynamic signals. During periods without movement, animals can rapidly transition into sleep, and the hemodynamic signals tied to arousal state changes can be several times larger than sensory-evoked responses. Given the outsized influence of facial and body motions and arousal signals in neural and hemodynamic signals, it is imperative to detect and monitor these events in experiments with un-anesthetized animals. Aim: To cover the importance of monitoring behavioral state in imaging experiments using un-anesthetized rodents, and describe how to incorporate detailed behavioral and physiological measurements in imaging experiments. Approach: We review the effects of movements and sleep-related signals (heart rate, respiration rate, electromyography, intracranial pressure, whisking, and other body movements) on brain hemodynamics and electrophysiological signals, with a focus on head-fixed experimental setup. We summarize the measurement methods currently used in animal models for detection of those behaviors and arousal changes. We then provide a guide on how to incorporate this measurements with functional brain imaging and electrophysiology measurements. Results: We provide a how-to guide on monitoring and interpreting a variety of physiological signals and their applications to NVC experiments in awake behaving mice. Conclusion: This guide facilitates the application of neuroimaging in awake animal models and provides neuroscientists with a standard approach for monitoring behavior and other associated physiological parameters in head-fixed animals.

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Increased Intracranial Pressure Attenuates the Pulsating Component of Cerebral Venous Outflow

Cited by 13 publications

References 30 publications

Intercompartmental communication between the cerebrospinal and adjacent spaces during intrathecal infusions in an acute ovine in-vivo model

Intercompartmental communication between the cerebrospinal and adjacent spaces during intrathecal infusions in an acute ovine in-vivo model

Phase-Contrast MRI Indices can Reflect Intracranial Compliance Deterioration Induced by Intra-Abdominal/ Thoracic Hypertension

Behavioral and physiological monitoring for awake neurovascular coupling experiments: a how-to guide

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