The Effects of Gradual Change in Head Positioning on the Relationship between Systemic and Cerebral Haemodynamic Parameters in Healthy Controls and Acute Ischaemic Stroke Patients

Posture-Induced Changes in Intraocular, Orbital, Cranial, Jugular Vein, and Arterial Pressures in a Porcine Model

Purpose

The purpose of this study was to determine posture-induced changes in arterial blood pressure (ABP), intraocular pressure (IOP), orbital pressure (Porb), intracranial pressure (ICP), and jugular vein pressure (JVP) at various tilt angles in an in vivo pig.

Methods

Anesthetized and ventilated pigs (n = 8) were placed prone on a tiltable operating table. ABP, IOP, Porb, ICP, and JVP were monitored while the table was tilted at various angles between 15 degrees head up tilt (HUT) and 25 degrees head down tilt (HDT) either in stepwise changes (5 degrees per step) or continuously. The mean pressure was calculated from digitized pressure waveforms from each compartment. For stepwise changes in tilt angle the pressures were plotted as a function of tilt angle. For continuous tilt changes, the pressures were plotted as a function of time.

Results

In the case of stepwise changes, ABP remained relatively stable whilst IOP, Porb, ICP, and JVP demonstrated significant differences between most angles (typically P < 0.0001). The difference was greatest for IOP (P < 0.0001) where the average IOP increased from 13.1 ± 1.23 mm Hg at 15 degrees HUT to 46.3 ± 2.03 mm Hg at 25 degrees HDT. The relationship between pressure and tilt angle was almost linear for ICP and JVP, and sigmoidal for IOP and Porb. Interestingly, the effect of changes in tilt angle occurred very rapidly, within a few seconds.

Conclusions

Our results in a pig model demonstrate that changes in posture (tilt angle) induce rapid changes in IOP, Porb, ICP, and JVP, with IOP affected most severely.

Promising Cerebral Blood Flow Enhancers in Acute Ischemic Stroke

Ischemic stroke presents a major global economic and public health burden. Although recent advances in available endovascular therapies show improved functional outcome, a good number of stroke patients are either ineligible or do not have access to these treatments. Also, robust collateral flow during acute ischemic stroke independently predicts the success of endovascular therapies and the outcome of stroke. Hence, adjunctive therapies for cerebral blood flow (CBF) enhancement are urgently needed. A very clear overview of the pial collaterals and the role of genetics are presented in this review. We review available evidence and advancement for potential therapies aimed at improving CBF during acute ischemic stroke. We identified heme-free soluble guanylate cyclase activators; Sanguinate, remote ischemic perconditioning; Fasudil, S1P agonists; and stimulation of the sphenopalatine ganglion as promising potential CBF-enhancing therapeutics requiring further investigation. Additionally, we outline and discuss the critical steps required to advance research strategies for clinically translatable CBF-enhancing agents in the context of acute ischemic stroke models.

Value of Hcy combined with Framingham score for predicting macrovascular disease in elderly patients with type 2 diabetes

To analyze the predictive value of homocysteine (Hcy) combined with the Framingham risk score for cardio- and cerebrovascular disease in elderly patients with type 2 diabetes mellitus (T2DM) to provide a reference for clinical treatment. We retrospectively reviewed the clinical data of 1036 elderly patients with T2DM admitted to our hospital between July 2017 and July 2022. The patients were divided into occurrence (n = 438) and control (n = 598) groups based on the incidence of cardio- or cerebrovascular disease. Univariate and multivariate logistic analyses were used to analyze the factors associated with cardio-cerebral small-vessel disease in the elderly patients with T2DM. The predictive value of Hcy combined with the Framingham score for cardio- and cerebrovascular diseases in elderly patients with T2DM was determined using receiver operating characteristic curves. Univariate analysis showed that the occurrence group had significantly higher Framingham score, systolic blood pressure (SBP), total cholesterol (TC), fasting blood glucose (FBG), 2-hour postprandial plasma glucose, Hcy, glycated hemoglobin, smoking history, and disease duration than the control group (all P < .05). Food preferences, sleep duration, physical exercise, high density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol levels were significantly lower in the occurrence group than in the control group (all P < .05). Multivariate logistic analysis showed that smoking history, duration of diabetes, Framingham score, SBP, TC, FBG, HDL-C, 2h postprandial plasma glucose, and Hcy levels were risk factors for cardio- and cerebrovascular disease in elderly patients with T2DM. The area under the curve for Hcy and Framingham scores was 0.741 (95% confidence interval [CI]: 0.635-1.871) and 0.717 (95% CI: 0.601-0.856), respectively. Hcy combined with the Framingham score demonstrated a significantly higher predictive value (0.852, 95% CI: 0.741-0.979). Long smoking history, long diabetes duration, high Framingham score, high SBP, high TC, high FBG, low HDL-C, and high Hcy levels are risk factors for cardio-cerebrovascular disease in elderly patients with T2DM. In addition, Hcy level combined with the Framingham score demonstrated superior predictive power for cardio- and cerebrovascular disease in elderly patients with T2DM.

Mobilization phases in traumatic brain injury

Mobilization in traumatic brain injury (TBI) have shown the improvement of length of stay, infection, long term weakness, and disability. Primary damage as a result of trauma's direct effect (skull fracture, hematoma, contusion, laceration, and nerve damage) and secondary damage caused by trauma's indirect effect (microvasculature damage and pro-inflammatory cytokine) result in reduced tissue perfusion & edema. These can be facilitated through mobilization, but several precautions must be recognized as mobilization itself may further deteriorate patient's condition. Very few studies have discussed in detail regarding mobilizing patients in TBI cases. Therefore, the scope of this review covers the detail of physiological effects, guideline, precautions, and technique of mobilization in patients with TBI.

Influence of postural changes on haemodynamics in internal carotid artery bifurcation aneurysm using numerical methods

Cerebral intracranial aneurysms are serious problems that can lead to stroke, coma, and even death. The effect of blood flow on cerebral aneurysms and their relationship with rupture are unknown. In addition, postural changes and their relevance to haemodynamics of blood flow are difficult to measure in vivo using clinical imaging alone. Computational simulations investigating the detailed haemodynamics in cerebral aneurysms have been developed in recent times not only to understand the progression and rupture but also for clinical evaluation and treatment. In the present study, the haemodynamics of a patient-specific case of a large aneurysm on the left side internal carotid bifurcation (LICA) and no aneurysm on the right side internal carotid bifurcation (RICA) was investigated. The simulation of these patient-specific models using fluid–structure interaction provides a valuable comparison of flow behavior between normal and aneurysm models. The influences of postural changes were investigated during standing, sleeping, and head-down (HD) position. Significant changes in flow were observed during the HD position and quit high arterial blood pressure in the internal carotid artery (ICA) aneurysm model was established when compared to the normal ICA model. The velocity increased abruptly during the HD position by more than four times (LICA and RICA) and wall shear stress by four times (LICA) to ten times (RICA). The complex spiral flow and higher pressures prevailing within the dome increase the risk of aneurysm rupture.