المؤلفون: Podgoršak, Anthony, Trimmel, Nina Eva, Oertel, Markus Florian, Arras, Margarete, Weisskopf, Miriam, Schmid Daners, Marianne, id_orcid:0 000-0002-6411-8871

المصدر: Fluids and Barriers of the CNS, 20

مصطلحات موضوعية: Arterial blood pressure, Cerebrospinal fluid, Hydrocephalus, Intracranial pressure, Ovine model, Physiology

الوصف: Introduction Most investigations into postural influences on craniospinal and adjacent physiology have been performed in anesthetized animals. A comprehensive study evaluating these physiologies while awake has yet been completed. Methods Six awake sheep had telemetric pressure sensors (100 Hz) implanted to measure intracranial, intrathecal, arterial, central venous, cranial, caudal, dorsal, and ventral intra-abdominal pressure (ICP, ITP, ABP, CVP, IAPcr, IAPcd, IAPds, IAPve, respectively). They were maneuvered upright by placing in a chair for two minutes; repeated 25 times over one month. Changes in mean and pulse pressure were calculated by comparing pre-chair, P0, with three phases during the maneuver: P1, chair entrance; P2, chair halftime; P3, prior to chair exit. Statistical significance (p ≤ .05) was assessed using repeated measures ANOVA. Results Significant mean pressure changes of (P1 − P0) and (P3 − P0) were measured at − 12.1 ± 3.1 and − 14.2 ± 3.0(p < .001), 40.8 ± 10.5 and 37.7 ± 3.5(p = .019), 9.7 ± 8.3 and 6.2 ± 5.3(p = .012), 22.3 ± 29.8 and 12.5 ± 12.1(p = .042), and 11.7 ± 3.9 and 9.0 ± 5.2(p = .014) mmHg, for ICP, ITP, IAPds, IAPcr, IAPca, respectively. For pulse pressures, significant changes of (P1 − P0) and (P3 − P0) were measured at − 1.3 ± 0.7 and − 2.0 ± 1.1(p < .001), 4.7 ± 2.3 and 1.4 ± 1.4(p < .001), 15.0 ± 10.2 and 7.3 ± 5.5(p < .001), − 0.7 ± 1.8 and − 1.7 ± 1.7(p < .001), − 1.3 ± 4.2 and − 1.4 ± 4.7(p = .006), and 0.3 ± 3.9 and − 1.0 ± 1.3(p < .001) mmHg, for ICP, ITP, ABP, IAPds, IAPcr, IAPca, respectively. Conclusions Pressures changed posture-dependently to differing extents. Changes were most pronounced immediately after entering upright posture (P1) and became less prominent over the chair duration (P2-to-P3), suggesting increased physiologic compensation. Dynamic changes in IAP varied across abdominal locations, motivating the abdominal cavity not to be considered as a unified entity, but sub-compartments with individual dynamics. ; ISSN:2045-8118

وصف الملف: application/application/pdf

العلاقة: info:eu-repo/semantics/altIdentifier/wos/001103140900001; info:eu-repo/grantAgreement/SNF/Projekte Lebenswissenschaften/184913; http://hdl.handle.net/20.500.11850/641250Test

الإتاحة: https://doi.org/20.500.11850/641250Test
https://doi.org/10.3929/ethz-b-000641250Test
https://doi.org/10.1186/s12987-023-00485-6Test
https://hdl.handle.net/20.500.11850/641250Test

المؤلفون: Podgoršak, Anthony, Trimmel, Nina Eva, Flürenbrock, Fabian, id_orcid:0 009-0008-1811-5769, Oertel, Markus Florian, Arras, Margarete, Weisskopf, Miriam, Schmid Daners, Marianne, id_orcid:0 000-0002-6411-8871

المصدر: Fluids and Barriers of the CNS, 20 (1)

مصطلحات موضوعية: Arterial blood pressure, Cerebrospinal fluid, Hydrocephalus, Intracranial pressure, Sheep model, Transfer function, Tilt testing

الوصف: Introduction Optimal shunt-based hydrocephalus treatments are heavily influenced by dynamic pressure behaviors between proximal and distal ends of shunt catheters. Posture-dependent craniospinal, arterial, venous, and abdominal dynamics thereby play an essential role. Methods An in-vivo ovine trial (n = 6) was conducted to evaluate communication between craniospinal, arterial, venous, and abdominal dynamics. Tilt-testing was performed between –13° and + 13° at 10-min intervals starting and ending at 0° prone position. Mean pressure, pulse pressure, and Pearson correlation (r) to the respective angle were calculated. Correlations are defined as strong: |r|≥ 0.7, mild: 0.3 <|r|< 0.7, and weak: |r|≤ 0.3. Transfer functions (TFs) between the arterial and adjacent compartments were derived. Results Strong correlations were observed between posture and: mean carotid/femoral arterial (r = − 0.97, r = − 0.87), intracranial, intrathecal (r = −0.98, r = 0.94), jugular (r = − 0.95), abdominal cranial, dorsal, caudal, and intravesical pressure (r = − 0.83, r = 0.84, r = − 0.73, r = 0.99) while mildly positive correlation exists between tilt and central venous pressure (r = 0.65). Only dorsal abdominal pulse pressure yielded a significant correlation to tilt (r = 0.21). TFs followed general lowpass behaviors with resonant peaks at 4.2 ± 0.4 and 11.5 ± 1.5 Hz followed by a mean roll-off of − 15.9 ± 6.0 dB/decade. Conclusions Tilt-tests with multi-compartmental recordings help elucidate craniospinal, arterial, venous, and abdominal dynamics, which is essential to optimize shunt-based therapy. Results motivate hydrostatic influences on mean pressure, with all pressures correlating to posture, with little influence on pulse pressure. TF results quantify the craniospinal, arterial, venous, and abdominal compartments as compliant systems and help pave the road for better quantitative models of the interaction between the craniospinal and adjacent spaces. ; ISSN:2045-8118

وصف الملف: application/application/pdf

العلاقة: info:eu-repo/semantics/altIdentifier/wos/001041570500001; info:eu-repo/grantAgreement/SNF/Projekte Lebenswissenschaften/184913; http://hdl.handle.net/20.500.11850/625123Test

الإتاحة: https://doi.org/20.500.11850/625123Test
https://doi.org/10.3929/ethz-b-000625123Test
https://doi.org/10.1186/s12987-023-00458-9Test
https://hdl.handle.net/20.500.11850/625123Test

المؤلفون: Podgoršak, Anthony, Trimmel, Nina Eva, Oertel, Markus Florian, Qvarlander, Sara, Arras, Margarete, Eklund, Anders, Weisskopf, Miriam, Schmid Daners, Marianne, id_orcid:0 000-0002-6411-8871

المصدر: Fluids and Barriers of the CNS, 19 (1)

مصطلحات موضوعية: Cerebrospinal fluid, Bolus infusion, Constant pressure infusion, Hydrocephalus, Intracranial pressure, Intrathecal pressure, Sheep model

الوصف: 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: ...

وصف الملف: application/application/pdf

العلاقة: info:eu-repo/semantics/altIdentifier/wos/000738696800001; info:eu-repo/grantAgreement/SNF/Projekte Lebenswissenschaften/184913; http://hdl.handle.net/20.500.11850/523060Test

الإتاحة: https://doi.org/20.500.11850/523060Test
https://doi.org/10.3929/ethz-b-000523060Test
https://doi.org/10.1186/s12987-021-00300-0Test
https://hdl.handle.net/20.500.11850/523060Test