Neurocritical care
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There is a growing interest in measuring cerebral autoregulation in patients with acute brain injury. Non-invasive finger photo-plethysmography (Finapres) is the method of choice to relate arterial blood pressure to changes in cerebral blood flow. Among acutely ill patients, however, peripheral vasoconstriction often limits the use of Finapres requiring direct intravascular blood pressure measurement. We evaluated how these two different forms of blood pressure monitoring affect the parameters of dynamic cerebral autoregulation (DCA). ⋯ Overall, both methods yield similar results and can be used for the assessment of DCA. However, there was a small but significant difference for both mean Mx and phase shift, which would need to be adjusted for during monitoring of patients when using both methods. When available, invasive arterial blood pressure monitoring may improve accuracy and thus should be the preferred method for DCA assessment in the ICU.
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Despite intensive research, neurological morbidity from delayed cerebral ischemia remains common after aneurysmal subarachnoid hemorrhage (SAH). In the current study, we evaluate the neuroprotective effects of a pH-dependent GluN2B subunit-selective NMDA receptor antagonist in a murine model of SAH. ⋯ These data demonstrate that use of a pH-dependent NMDA antagonist has the potential to work selectively in areas of ischemia known to undergo acidic pH shifts, and thus may be associated with selective regional efficacy and fewer behavioral side effects than non-selective NMDA antagonists.
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In order to deliver specialized neurocritical care (NCC) without a dedicated neurological intensive care unit (ICU), we established a virtual NCC unit within an existing mixed level III ICU. This initiative required changes to patient allocation, physician staffing, and care protocols. In advance of its implementation, we gaged readiness, assessed barriers, and solicited feedback from staff. ⋯ A new workable model for NCC has been developed, facilitated by this analysis. Steps to overcome barriers demonstrated in this study include additional educational measures, changes to the rounding protocols, and patient allocation algorithms.
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Observational Study
Red Blood Cell Transfusion Increases the Risk of Thrombotic Events in Patients with Subarachnoid Hemorrhage.
Red blood cell transfusion (RBCT) may increase the risk of thrombotic events (TE) in patients with subarachnoid hemorrhage (SAH) through changes induced by storage coupled with SAH-related hypercoagulability. We sought to investigate the association between RBCT and the risk of TE in patients with SAH. ⋯ RBCT is associated with an increased risk of TE and VTE in SAH patients. A dose-dependent relationship exists between number of units transfused and thrombosis. Age of blood does not appear to play a role.
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Babies are frequently exposed to cerebral hypoxia and ischemia (H/I) during the perinatal period as a result of stroke, problems with delivery or post delivery respiratory management. The sole FDA approved treatment for acute stroke is tissue-type plasminogen activator (tPA). Endogenous tPA is upregulated and potentiates impairment of pial artery dilation in response to hypotension after H/I in pigs. Mitogen-activated protein kinase (MAPK), a family of at least 3 kinases, ERK, p38 and JNK, is also upregulated after H/I, with ERK contributing to impaired vasodilation. This study examined the hypothesis that H/I aggravates the vascular response to two important procontractile mediators released during CNS ischemia, endothelin-1 (ET-1) and thromboxane, which is further enhanced by tPA and ERK MAPK. ⋯ These data indicate that H/I aggravates ET-1 and thromboxane mediated cerebral vasoconstriction by upregulating endogenous tPA and ERK MAPK.