Cerebral autoregulation (CA) is a protective mechanism that maintains cerebral blood flow at a relatively constant level despite fluctuations of cerebral perfusion pressure or arterial blood pressure. It is a universal physiological mechanism that may involve myogenic, neural control as well as metabolic regulations of cerebral vasculature in response to changes in pressure or cerebral blood flow. Traditionally, CA has been represented by a sigmoid curve with a wide plateau between about 50 mm Hg and 170 mm Hg of steady-state changes in mean arterial pressure, defined as static CA. With the advent of transcranial Doppler, measurement of cerebral blood flow in response to transient changes in arterial pressure has been used to assess dynamic CA. However, a gold standard for measuring CA is not currently available. Stroke has been the leading cause of long-term adult disability throughout the world. A better understanding of CA and its response to pathological derangements can help assess the severity of stroke, guide management decisions, assess response to interventions and provide prognostic information. The objective of this review is to provide a comprehensive insight about physiology of autoregulation, measurement methodologies and clinical applications in stroke to help build a consensus for what should be included in an internationally agreed protocol for CA testing and monitoring, and to promote its translation into clinical bedside practice for stroke management.

The extracellular P signal acquired from the human head using nonlocalized P MRS contains a significant component likely contributed by peripheral blood and CSF in meninges that must be removed in order to use this signal as an endogenous probe for measuring extracellular pH and other properties in the brain.

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Background and Purpose: Cerebral microbleeds (CMB) are reported to be frequent in moyamoya disease (MMD) and moyamoya syndrome (MMS) in the Asian population. It is associated with an increased risk of intracerebral hemorrhage. The significance of CMB in MMD/MMS in non-Asian populations has not been well established. Our study aimed to investigate the prevalence of CMB in MMD/MMS in a moymoya cohort with a majority of non-Asians and to identify risk factors for developing a CMB and its predictive value for subsequent vascular events. Methods: The moyamoya database was compiled by screening for MMD/MMS among patients admitted to the Zale-Lipshy University Hospital at the University of Texas Southwestern Medical Center. We identified and analyzed data of 67 patients with MMD or MMS. Patients were characterized as CMB+ or CMB– based on MRI findings. In CMB+ patients, the total number and location of CMB were identified. Univariate and multivariate logistic regression were used to identify risk factors for developing CMB and whether CMB are associated with the development of subsequent vascular events. Results: Out of a total of 67 patients, 11 (16%) had CMB. Males had significantly higher odds of having CMB as compared to females (OR 1.76; 95% CI 1.40–24.3, p = 0.021). The incidence of CMB was also associated with age at diagnosis (mean age of CMB+ patients vs. CMB– patients: 44 vs. 34 years, respectively, p = 0.024), smoking (p = 0.006), and hemorrhagic stroke at presentation (p = 0.034). Logistic regression with multivariate analysis found that gender and age at diagnosis remained statistically significant. New ischemic events occurred in 2 (20%) out of 10 CMB+ patients and 13 (23%) out of 55 CMB– patients, respectively (p = 0.79). While 2 (3%) CMB– patients had a new cerebral hemorrhage during follow-up, none of the CMB+ patients did. Conclusions: CMB are less prevalent in MMD/MMS in the USA than in Asia. An older age at diagnosis and male gender were associated with CMB. The presence of CMB was not associated with an increased risk of a subsequent ischemic or hemorrhagic stroke.

Objective: Documenting vital signs and National Institutes of Health Stroke Scale (NIHSS) once every 15 minutes after intravenous thrombolytic therapy for acute ischemic stroke is often used as a metric to assess the quality of care. This study explores the association between "once every 15 minutes" documentation and stroke outcomes.Methods: This is a retrospective study of the first 2 hours of vital signs and NIHSS documentation after thrombolytic stroke therapy. Sociodemographic and clinical data, including NIHSS, temperature, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, and respiratory rate, were abstracted from the medical record. Missing documentation was examined for association with modified Rankin Scale (mRS) scores and neurologic changes.Result: Among 84 patients with a mean age of 68.8 years, there were 2276 documented assessments from an expected 3780. There were 104 clinically significant changes in 1 or more index variables. The most commonly missed documentation occurred during interventional radiology. After controlling for admission NIHSS, there was no significant relationship between the completeness of documentation and discharge mRS score (r 2 = 0.047, P = .0561), nor between vital sign documentation and discharge mRS (r 2 = 0.003, P = .6338).Conclusion: Frequency of documentation does not reflect the quality of care during the early phase of acute stroke treatment.