Reduced CBF recovery detected by longitudinal 3D-SSP SPECT analyses predicts outcome of postoperative patients after subarachnoid haemorrhage

Performance of Electrical Velocimetry for Noninvasive Cardiac Output Measurements in Perioperative Patients After Subarachnoid Hemorrhage

BACKGROUND

Fluid therapy guided by cardiac output measurements is of particular importance for adequate cerebral perfusion and oxygenation in neurosurgical patients. We examined the usefulness of a noninvasive electrical velocimetry (EV) device based on the thoracic bioimpedance method for perioperative hemodynamic monitoring in patients after aneurysmal subarachnoid hemorrhage.

PATIENTS AND METHODS

In total, 18 patients who underwent surgical clipping or endovascular coiling for ruptured aneurysms were examined prospectively. Simultaneous cardiac index (CI) measurements obtained with EV (CIEV) and reference transpulmonary thermodilution (CITPTD) were compared. A total of 223 pairs of data were collected.

RESULTS

A significant correlation was found between CIEV and CITPTD (r=0.86; P<0.001). Bland and Altman analysis revealed a bias between CIEV and CITPTD of -0.06 L/min/m, with limits of agreement of ±1.14 L/min/m and a percentage error of 33%. Although the percentage error for overall data was higher than the acceptable limit of 30%, subgroup analysis during the postoperative phase showed better agreement (23% vs. 42% during the intraprocedure phase). Four-quadrant plot and polar plot analyses showed fair-to-poor trending abilities (concordance rate of 90% to 91%, angular bias of +17 degrees, radial limits of agreement between ±37 and ±40 degrees, and polar concordance rate of 72% to 75%), including the subgroup analysis.

CONCLUSIONS

Absolute CI values obtained from EV and TPTD are not interchangeable with TPTD for perioperative use in subarachnoid hemorrhage patients. However, considering the moderate levels of agreement with marginal trending ability during the early postoperative phase, this user-friendly device can provide an attractive monitoring option during neurocritical care.

Rapamycin protects against early brain injury independent of cerebral blood flow changes in a mouse model of subarachnoid haemorrhage

We evaluated the neuroprotective role of rapamycin, a mammalian target of rapamycin (mTOR) kinase inhibitor, in cerebral ischaemia and locomotor function in a mouse model of subarachnoid haemorrhage (SAH). Pretreatment with rapamycin, an mTOR kinase inhibitor, resulted in better recovery from cerebral hypoxia early after SAH than control (P < .05), while the values of peak flow velocity in the middle cerebral artery did not change significantly (P > .05). Average distance travelled and the ratio of central-area distance/total travelled distance determined by open-field test after day 14 was significantly higher in mice pretreated with rapamycin than in control mice (P < .05). Inhibition of the mTOR pathway could be protective against post-SAH early brain injury, ameliorating brain tissue hypoxia and locomotor hypoactivity.

Central action of rapamycin on early ischemic injury and related cardiac depression following experimental subarachnoid hemorrhage

Early brain injury and related cardiac consequences play a key role in the devastating outcomes after subarachnoid hemorrhage (SAH). We reported that rapamycin exerts neuroprotection against cortical hypoxia early after SAH, but its mechanism is poorly understood. This in vivo study aimed to determine the potential role of the transcription factor STAT3 in the rapamycin-mediated neuroprotection in a mouse model of SAH. Forty C57BL/6 N mice were treated with an intracerebroventricular injection of rapamycin or vehicle (control) given after SAH induction by a filament perforation method, with or without STAT3 (Stattic) or ERK (PD98059) inhibitor pretreatment. Cerebral blood flow signals (%vascularity), brain tissue oxygen saturation (SbtO₂), and cardiac output (CO) were analyzed using an ultrasound/photoacoustic imaging system. Clinically relevant neurocardiac depression was notable in severe SAH mice. Rapamycin improved %vascularity, SbtO₂, and CO on day 1 after SAH onset. The beneficial effects of rapamycin on cerebral blood flow and oxygenation persisted until day 3, resulting in a significant reduction in post-SAH new cerebral infarctions and survival, as well as improved neurological functions, compared to the control group. All of the effects were attenuated by pretreatment with Stattic or PD98059. These data suggest that ERK and JAK/STAT3 pathways play an important role in the neurocardiac protection by rapamycin after SAH. We propose that rapamycin is a novel pharmacological strategy to target STAT3 activation, with a possible crosstalk through the ERK pathway, for the treatment of post-SAH early brain injury.

Posterior Associative and Cingulate Cortex Involvement of Brain Single-Photon Emission Computed Tomography (SPECT) Imaging in Semantic Dementia with Probable Alzheimer Disease Pathology: A Case Report

Patient: Male, 61

Final Diagnosis: Semantic dementia

Symptoms: Primary progressive aphasia

Medication: —

Clinical Procedure: Neuroimaging

Specialty: Nuclear Medicine

Preceding functional tooth loss delays recovery from acute cerebral hypoxia and locomotor hypoactivity after murine subarachnoid haemorrhage

Tooth loss and related changes in the functionality may lead to worse outcome of stroke patients, but the effect on hemorrhagic stroke remains unclear. This study aimed to determine the impact of impaired masticatory function on acute cerebral oxygenation and locomotor activity after experimental subarachnoid haemorrhage (SAH). Twenty C57BL/6 mice with (MC-treated group) or without (control group) prior treatment of cutting off the upper molars were subjected to SAH by endovascular perforation. Grading of SAH and acute cerebral infarction were assessed by MR images. Brain tissue oxygen saturation (SbtO₂ ) by photoacoustic imaging and parameters related to locomotor activity by open-field test were analyzed serially after SAH. In all mice, global SbtO2 depression was notable immediately after SAH induction (P <.001), which recovered close to the baseline levels until day 3. However, MC-treated mice demonstrated a prolonged relative cerebral hypoxia (<40% of the baseline SbtO2) as compared to the control (3 ± 1 vs 1 ± 1 days; P <.05). The average distance travelled on day 7 and the ratio of central-area distance/total travelled distance by open-field test between days 7 and 14 were significantly lower in MC-treated mice than in the control mice (P <.05), although the occurrences of new infarction were not statistically different (P >.05). These data suggest a possible link between preceding masticatory impairment and early brain injury to deteriorate neurobehavioural function in patients after SAH.