scholarly journals Compliance of the cerebrospinal space: comparison of three methods

2021 ◽  
Author(s):  
Agnieszka Kazimierska ◽  
Magdalena Kasprowicz ◽  
Marek Czosnyka ◽  
Michał M. Placek ◽  
Olivier Baledent ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Direct Method ◽  
Correlation Coefficients ◽  
Normal Pressure ◽  
Indirect Methods ◽  
Arterial Blood ◽  
Increased Risk ◽  
The Mean ◽  
Time Courses ◽  
Arterial Blood Volume

Abstract Background Cerebrospinal compliance describes the ability of the cerebrospinal space to buffer changes in volume. Diminished compliance is associated with increased risk of potentially threatening increases in intracranial pressure (ICP) when changes in cerebrospinal volume occur. However, despite various methods of estimation proposed so far, compliance is seldom used in clinical practice. This study aimed to compare three measures of cerebrospinal compliance. Methods ICP recordings from 36 normal-pressure hydrocephalus patients who underwent infusion tests with parallel recording of transcranial Doppler blood flow velocity were retrospectively analysed. Three methods were used to calculate compliance estimates during changes in the mean ICP induced by infusion of fluid into the cerebrospinal fluid space: (a) based on Marmarou’s model of cerebrospinal fluid dynamics (CCSF), (b) based on the evaluation of changes in cerebral arterial blood volume (CCaBV), and (c) based on the amplitudes of peaks P1 and P2 of ICP pulse waveform (CP1/P2). Results Increase in ICP caused a significant decrease in all compliance estimates (p < 0.0001). Time courses of compliance estimators were strongly positively correlated with each other (group-averaged Spearman correlation coefficients: 0.94 [0.88–0.97] for CCSF vs. CCaBV, 0.77 [0.63–0.91] for CCSF vs. CP1/P2, and 0.68 [0.48–0.91] for CCaBV vs. CP1/P2). Conclusions Indirect methods, CCaBV and CP1/P2, allow for the assessment of relative changes in cerebrospinal compliance and produce results exhibiting good correlation with the direct method of volumetric manipulation. This opens the possibility of monitoring relative changes in compliance continuously.

scholarly journals Role of Oxidative Stress as a Marker of Cardiovascular Risk in Children on Regular Hemodialysis

2021 ◽  
pp. 416-421
Author(s):  
Muhammad Abrar ◽  
Mazhar Nadeem ◽  
Sunila Fatima
Keyword(s):  
Oxidative Stress ◽  
Cardiovascular Risk ◽  
Prognostic Significance ◽  
Public Health Problem ◽  
Dialysis Session ◽  
Major Public Health Problem ◽  
Arterial Blood ◽  
Increased Risk ◽  
The Mean ◽  
Regular Hemodialysis

Introduction: Chronic kidney disease (CKD) is a major public health problem worldwide, and its main consequences include loss of renal function leading to end-stage renal disease (ESRD), increased risk of cardiovascular disease (CVD), significant increase in morbidity and mortality, and a decrease in health-related quality of life. Aims and Objectives: The basic aim of the study is to analyze the oxidative stress and total antioxidant capacity as a biomarker of cardiovascular risk in those children who are on regular hemodialysis. Materials and Methods: This cross sectional study was conducted at DHQ hospital, Faisalabad during July 2020 to January 2021. The data were collected from the age of less than 18 years children of both sexes. There were 50 children who was selected for this study. At the time of the study, all the patients were on regular three HD sessions per week. In HD patients, venous blood samples were drawn immediately before and after hemodialysis session. Baseline laboratory investigations were carried out for all patients and controls including complete blood count, serum urea and creatinine, arterial pH, arterial blood gases and infection screening, which included blood and urinary cultures by standard methods.  Results: The data were collected from 50 dialysis patients. The mean age of this study is 15years. We collected all the demographic data of patients. The mean value of Urea is 64.34±2.44 mg/dl). At before-dialysis session, duration of disease positively correlated with TPX (r = 0.969, P <0.001), but, negatively correlated with TAC (r = −0.469, P <0.002). At after-dialysis session, HIF-1α negatively correlated with each of TPX (r = −0.529, P <0.001) and OSI (r = −0.459, P <0.003); while, OSI positively correlated with TPX (r = 0.944, P <0.001). Conclusion: It is concluded that HD patients, the clinical and prognostic significance of oxidative status associated with cardiovascular risk factors is very different from the general population. Although a direct causality cannot be inferred from such kind of correlative investigations.

Changes in brain surface pH during acute isocapnic metabolic acidosis and alkalosis

1981 ◽  
Vol 51 (2) ◽  
pp. 276-281 ◽  
Author(s):  
S. Javaheri ◽  
A. Clendening ◽  
N. Papadakis ◽  
J. S. Brody
Keyword(s):  
Cerebrospinal Fluid ◽  
Metabolic Acidosis ◽  
Interstitial Fluid ◽  
Acid Base ◽  
Surface Ph ◽  
Brain Surface ◽  
Arterial Blood ◽  
Anesthetized Dogs ◽  
The Mean ◽  
The Brain

It has been thought that the blood-brain barrier is relatively impermeable to changes in arterial blood H+ and OH- concentrations. We have measured the brain surface pH during 30 min of isocapnic metabolic acidosis or alkalosis induced by intravenous infusion of 0.2 N HCl or NaOH in anesthetized dogs. The mean brain surface pH fell significantly by 0.06 and rose by 0.04 pH units during HCl or NaOH infusion, respectively. Respective changes were also observed in the calculated cerebral interstitial fluid [HCO-3]. There were no significant changes in cisternal cerebrospinal fluid acid-base variables. It is concluded that changes in arterial blood H+ and OH- concentrations are reflected in brain surface pH relatively quickly. Such changes may contribute to acute respiratory adaptations in metabolic acidosis and alkalosis.

scholarly journals Correlation of Primate Caudate Neural Activity and Saccade Parameters in Reward-Oriented Behavior

2003 ◽  
Vol 89 (4) ◽  
pp. 1774-1783 ◽  
Author(s):  
Hideaki Itoh ◽  
Hiroyuki Nakahara ◽  
Okihide Hikosaka ◽  
Reiko Kawagoe ◽  
Yoriko Takikawa ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Time Window ◽  
Correlation Coefficients ◽  
Saccade Latency ◽  
Major Type ◽  
Projection Neurons ◽  
Saccade Velocity ◽  
Trial Basis ◽  
The Mean ◽  
Time Courses

Changes in the reward context are associated with changes in neuronal activity in the basal ganglia as well as changes in motor outputs. A typical example is found in the caudate (CD) projection neurons and saccade parameters. It raised the possibility that the changes in CD neuronal activity contribute to the changes in saccade parameters. To examine this possibility, we calculated the correlation coefficients (CORs) of the firing rates of each neuron with saccade parameters (peak saccade velocity and latency) on a trial-by-trial basis. We then calculated the mean CORs separately for two CD populations: reward-enhanced type neurons (RENs) that showed enhanced activity and reward-depressed type neurons (RDNs) that showed depressed activity when reward was expected. The activity of RENs was positively correlated with the saccadic peak velocity and negatively correlated with the saccade latency. The activity of RDNs was not significantly correlated with the saccade parameters. We further analyzed the CORs for RENs, a major type of CD neurons. First, we examined the time courses of the CORs using a moving time window (duration: 200 ms). The positive correlation with the saccade velocity and the negative correlation with the saccade latency were present not only in the peri-saccadic period but also during the pre- and postcue periods. Second, we asked whether the CORs with the saccade parameters were direction-selective. A majority of RENs were more active before contralateral saccades (contralateral-preferring neurons) and their activity was correlated more strongly with contralateral saccades than with ipsilateral saccades. A minority of RENs, ipsilateral-preferring neurons, showed no such preference. These results are consistent with the hypothesis that CD neuronal activity exerts facilitatory effects on contralateral saccades and that the effects start well before saccade execution. Furthermore, a multiple regression analysis indicated that changes in activity of some, but not all, CD neurons could be explained by changes in saccade parameters; a major determinant was reward context (presence or absence of reward). These results suggest that, while a majority of CD neurons receive reward-related signals, only some of them can make a significant contribution to change saccadic outputs based on expected reward.

scholarly journals Aspirin is associated with an increased risk of subdural hematoma in normal-pressure hydrocephalus patients following shunt implantation

2015 ◽  
Vol 123 (2) ◽  
pp. 423-426 ◽  
Author(s):  
Peter Birkeland ◽  
Jens Lauritsen ◽  
Frantz Rom Poulsen
Keyword(s):  
Cerebrospinal Fluid ◽  
Normal Pressure Hydrocephalus ◽  
Subdural Hematoma ◽  
Normal Pressure ◽  
Aspirin Therapy ◽  
Cerebrospinal Fluid Shunt ◽  
Survival Estimate ◽  
Therapy Regimen ◽  
Shunt Implantation ◽  
Increased Risk

OBJECT In this paper the authors investigate whether shunt-treated patients with normal-pressure hydrocephalus receiving aspirin therapy are at increased risk of developing subdural hematoma (SDH). METHODS Records from 80 consecutive patients who had undergone implantation of a cerebrospinal fluid shunt for the treatment of normal-pressure hydrocephalus were retrospectively reviewed. RESULTS Eleven cases of symptomatic SDH occurred, all among patients receiving aspirin or clopidogrel. The 5-year survival estimate was 0.3 (p < 0.0001) for users of aspirin and the hazard ratio was 12.8 (95% CI 3.1–53). CONCLUSIONS Patients on an aspirin therapy regimen have a markedly increased risk of SDH after a shunt has been implanted for the treatment of normal-pressure hydrocephalus. Users of clopidogrel may have an even greater risk.

scholarly journals Cerebrospinal fluid closing pressure-guided tap test for the diagnosis of idiopathic normal pressure hydrocephalus: A descriptive cross-sectional study

2020 ◽  
Vol 11 ◽  
pp. 315
Author(s):  
Diego Fernando Gómez-Amarillo ◽  
Luis Fernando Pulido ◽  
Isabella Mejía ◽  
Catalina García-Baena ◽  
María Fernanda Cárdenas ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Opening Pressure ◽  
Cross Sectional ◽  
Tap Test ◽  
The Mean ◽  
Closing Pressure

Background: Tap test improves symptoms of idiopathic normal pressure hydrocephalus (iNPH); hence, it is widely used as a diagnostic procedure. However, it has a low sensitivity and there is no consensus on the parameters that should be used nor the volume to be extracted. We propose draining cerebrospinal fluid (CSF) during tap test until a closing pressure of 0 cm H2O is reached as a standard practice. We use this method with all our patients at our clinic. Methods: This is a descriptive cross-sectional study where all patients with presumptive diagnosis of iNPH from January 2014 to December 2019 were included in the study. We used a univariate descriptive analysis and stratified analysis to compare the opening pressure and the volume of CSF extracted during the lumbar puncture, between patients in whom a diagnosis of iNPH was confirmed and those in which it was discarded. Results: A total of 92 patients were included in the study. The mean age at the time of presentation was 79.4 years and 63 patients were male. The diagnosis of iNPH was confirmed in 73.9% patients. The mean opening pressure was 14.4 cm H2O mean volume of CSF extracted was 43.4 mL. Conclusion: CSF extraction guided by a closing pressure of 0 cm H2O instead of tap test with a fixed volume of CSF alone may be an effective method of optimizing iNPH symptomatic improvement and diagnosis.

Effect of systemic arterial hypotension on the rate of cerebrospinal fluid formation in dogs

1974 ◽  
Vol 41 (3) ◽  
pp. 350-355 ◽  
Author(s):  
Michael E. Carey ◽  
A. Richard Vela
Keyword(s):  
Blood Pressure ◽  
Cerebrospinal Fluid ◽  
Mean Arterial Blood Pressure ◽  
Content Type ◽  
Arterial Blood ◽  
Ventriculocisternal Perfusion ◽  
Fluid Formation ◽  
The Mean ◽  
Csf Production ◽  
Fine Print

✓The rate of cerebrospinal fluid (CSF) production in dogs was measured by ventriculocisternal perfusion with artificial CSF containing inulin. In normotensive animals, the average CSF production was 36 ± 6 µl/min. When the mean arterial blood pressure was reduced to 62 ± 1 mm Hg, the CSF production fell to 22 ± 5 µl/min, a 39% reduction in fluid formation. The authors briefly discuss various hypotheses to explain this reduction.

Isocapnic hyperpnea in awake ponies during inspiration of 4% CO2

1979 ◽  
Vol 47 (2) ◽  
pp. 445-452 ◽  
Author(s):  
J. A. Orr ◽  
D. W. Busija
Keyword(s):  
Cerebrospinal Fluid ◽  
Direct Measurement ◽  
Arterial Blood ◽  
The Mean ◽  
Chemical Stimuli ◽  
Isocapnic Hyperpnea

Unanesthetized ponies were given 4% CO2 (inspired CO2 pressure = 28 Torr) to breathe at two levels of arterial O2 pressure (PaO2): 1) near 75 Torr and 2) near 200 Torr. During 4% CO2 breathing, at either level of PaO2, the mean arterial CO2 pressure (PaCO2) was unchanged from control measurements (control measurements were made at the same PaO2, but with no CO2 in inspired air), suggesting that awake ponies can “clear” 4% CO2. The ability of individual ponies to clear 4% CO2 was quite variable: some ponies did not clear 4% CO2 and others cleared 4% CO2 on one day but not on the following day. Based on the average of 20 experiments, however, PaCO2 was unchanged from 40 Torr during inspiration of 4% CO2. Direct measurement of chemical stimuli to breathing in arterial blood and cisternal cerebrospinal fluid indicate that ventilation increased during CO2 breathing even though PaCO2, pHa, PaO2, and CSF pH were not changed in a direction that might explain the accompanying change in ventilation. The authors suggest that stimuli to receptors other than peripheral or medullary chemoreceptors may be responsible for the reported “isocapnic hyperpnea.”

Cerebrospinal fluid drainage as influenced by ventricular pressure in the rabbit

1982 ◽  
Vol 56 (6) ◽  
pp. 790-797 ◽  
Author(s):  
J. Gordon McComb ◽  
Hugh Davson ◽  
Shigeyo Hyman ◽  
Martin H. Weiss
Keyword(s):  
Cerebrospinal Fluid ◽  
Indigo Carmine ◽  
Normal Pressure ◽  
Cervical Lymph Nodes ◽  
Content Type ◽  
Cisterna Magna ◽  
Arterial Circulation ◽  
Sagittal Sinus ◽  
Arterial Blood ◽  
Ventriculocisternal Perfusion

✓ Artificial cerebrospinal fluid (CSF) containing radioisotope iodinated (125I) serum albumin (RISA) and either blue dextran or indigo carmine was given to white New Zealand rabbits over 4 hours. In one group it was given by ventriculocisternal perfusion, in one by ventricular infusion, and in one by cisterna magna infusion. Blood was sampled continuously from the superior sagittal sinus (SSS) or intermittently from the systemic arterial circulation. Removal of CSF from the cisterna magna during the ventriculocisternal perfusion kept the intracranial pressure (ICP) at 0 to 5 torr, whereas ventricular or cisterna magna infusion raised the ICP to 20 to 30 torr and 15 to 20 torr, respectively. In the two groups with raised ICP, an increased concentration of RISA was present in the optic nerves, olfactory bulbs, episcleral tissue, and deep cervical lymph nodes; but this was not found in the group with normal ICP. In all three groups, the concentration of RISA in the SSS blood was the same as in the systemic arterial blood. The concentration gradient of RISA across the cerebral cortex was similar in both the ventriculocisternal perfusion and the ventricular infusion groups. With cisterna magna infusion, the concentration of RISA was the same on the cortical surface and less in the ventricles compared with the ventricular infusion. It is concluded that, with elevated ICP, CSF drained via pathways that are less evident under normal pressure. Drainage of CSF was similar irrespective of whether the infusion site was the ventricles or cisterna magna. It did not appear that acute dilatation of the ventricles during ventricular infusion compromised the subarachnoid space over the surface of the hemisphere, as the concentration of RISA on the convexities and in the SSS blood did not significantly differ between the groups. Transcortical bulk transfer of CSF was not evident with raised ICP.

scholarly journals Validation of Davson’s equation in patients suffering from idiopathic Normal Pressure Hydrocephalus

2018 ◽  
Author(s):  
Afroditi-Despina Lalou ◽  
Virginia Levrini ◽  
Matthew Garnett ◽  
Eva Nabbanja ◽  
Dong-Joo Kim ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Normal Pressure Hydrocephalus ◽  
Fundamental Equation ◽  
Indirect Evidence ◽  
Correlation Coefficients ◽  
Normal Pressure ◽  
Hospital Data ◽  
Sagittal Sinus ◽  
Key Factor ◽  
The Relationship

AbstractIntroductionThe so called Davson’s equation relates baseline intracranial pressure (ICP) to resistance to cerebrospinal fluid outflow (Rout), formation of cerebrospinal fluid (If) and sagittal sinus pressure (PSS) There is a controversy over whether this fundamental equation is applicable in patients with normal pressure hydrocephalus (NPH). We investigated the relationship between Rout and ICP and also other compensatory, clinical and demographic parameters in NPH patients.MethodWe carried out a retrospective study of 229 patients with primary NPH who had undergone constant-rate infusion studies in our hospital. Data was recorded and processed using ICM+ software. Relationships between variables were sought by calculating Pearson product correlation coefficients and p values.ResultsWe found a significant, albeit weak, relationship between ICP and Rout (R=0.17, p=0.0049), Rout and peak-to-peak amplitude of ICP (AMP) (R=0.27, p=3.577e−05) and Rout and age (R=0.16, p=0.01306).ConclusionsThe relationship found between ICP and Rout provides indirect evidence to support disturbed Cerebrospinal fluid circulation as a key factor in disturbed CSF dynamics in NPH. Weak correlation may indicate that other factors: variable Pss and formation of CSF outflow contribute heavily to linear model expressed by Davson’s equation.

scholarly journals Tracking blood pressure changes by means of non-invasive intermittent blood pressure measurements in clinical application

2021 ◽  
Vol 7 (2) ◽  
pp. 815-818
Author(s):  
Robert Huhle ◽  
Thorsten Richter ◽  
Marcelo Gama de Abreu
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Pressure Range ◽  
Tracking Error ◽  
Correlation Coefficients ◽  
Non Invasive ◽  
Arterial Blood ◽  
The Mean ◽  
Blood Pressure Range ◽  
Pressure Changes

Abstract Considering accuracy/precision cut-offs of 5 ± 8 mmHg and cut-off values for inter-class correlation coefficients (ICC=0.37...1, from DIN EN ISO 81060-2), absolute and relative errors in time independent measurement of blood pressure changes with non-invasive intermittent devices (NiBP) are derived mathematically for mean arterial blood pressure range of 40-180 mmHg. As a clinically relevant value for change of arterial blood pressure 20% of the baseline blood pressure is considered. The mean ratio between the change of BP measured by the NiBP and measured by the invasive reference device (TE%) were proposed as quality measure for the evaluation of NiBP device tracking capability. The proposed measure TE%is theoretically independent of absolute accuracy but depends on precision and ICC of a device. NiBP devices show considerable maximum TE% of 41% in tracking mean blood pressure changes respectively. In 10% of the measurements in the low blood pressure range TE% exceeding 100%. The mean 50th/90th TE% percentile over the whole blood pressure range were 25/61%, respectively. Furthermore, TE% was relatively insensitive to assumed blood pressure range but sensitive to ICC. NiBP devices have high relative error in tracking blood pressure changes that make those devices not well-suited for tracking blood pressure changes. The proposed tracking error allows the definition of reasonable accuracy/precision requirements of NBP devices.

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