Neurocritical care
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The phosphodiesterase-5 inhibitor sildenafil has been shown to attenuate delayed cerebral ischemia (DCI) and improve neurologic function in experimental subarachnoid hemorrhage (SAH). We recently demonstrated that it could improve cerebral vasospasm (CVS) in humans after SAH. However, successful therapies for DCI must also restore cerebral blood flow (CBF) and/or autoregulatory capacity. In this study, we tested the effects of sildenafil on CBF in SAH patients at-risk for DCI. ⋯ Infusion of sildenafil does not lead to a change in global or regional perfusion despite a significant reduction in cerebral perfusion pressure. While this could reflect the ineffectiveness of sildenafil-induced proximal vasodilatation to alter brain perfusion, it also suggests that cerebral autoregulatory function was preserved in this group. Future studies should assess whether sildenafil can restore or enhance autoregulation after SAH.
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The etiology of altered consciousness in patients with high-grade aneurysmal subarachnoid hemorrhage (SAH) is not thoroughly understood. We hypothesized that decreased cerebral blood flow (CBF) in brain regions critical to consciousness may contribute. ⋯ In this retrospective pilot study, we did not identify significant correlations between CBF and admission GCS, admission HH class, or MRI GCS for any DMN node. Potential explanations for these findings include small sample size, ASL data acquisition at variable times after SAH onset, and CBF analysis in DMN nodes that may not reflect the functional integrity of the entire network. High inter-rater reliability suggests ASL measurements of CBF within DMN nodes are reproducible. Larger prospective studies are needed to elucidate whether decreased cerebral perfusion contributes to altered consciousness in SAH.
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Infections are a common medical complication in hemorrhagic stroke patients, with vancomycin commonly used as empiric therapy. The purpose of this study was to evaluate the pharmacokinetic parameters of vancomycin in hemorrhagic stroke patients. ⋯ Patients with hemorrhagic stroke exhibited pharmacokinetic alterations favoring increased elimination of vancomycin when compared to predicted pharmacokinetic parameters based on population data. This may result in underexposure to vancomycin, leading to treatment failure and other medical complications.
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Severe traumatic brain injury is associated with a multi-systemic response and changes in metabolic demand. Patients requiring intracranial pressure monitoring or cerebrospinal fluid diversion, often signifies a greater severity of injury. For this group, the association between RBC transfusion, transfusion thresholds, and clinical recovery is unknown. In this study, we studied the association between transfusion and clinical recovery for severe traumatic brain injury patients requiring external ventricular drain or intracranial pressure monitor placement. ⋯ From our studies, we demonstrate no significant clinical benefit associated with stratified transfusion goals; however, there was a decrease in length of hospitalization for patients with transfusion thresholds of Hgb ≥ 8 mg/dL. Larger, randomized controlled trials may be required to more accurately assess outcomes in this patient population. In patients admitted for primary severe traumatic brain injury, we demonstrate no significant clinical benefit associated with stratified transfusion goals; however, there was a noticeable decrease in length of hospitalization for patients with transfusion thresholds of Hgb ≥ 8 mg/dL. Larger, randomized controlled trials may be required to more accurately assess outcomes in this patient population.
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This study investigated if cerebral blood flow (CBF) regulation by changes of the arterial partial pressure of carbon dioxide (PaCO2) can be used therapeutically to increase CBF and improve neurological outcome after subarachnoid hemorrhage (SAH). ⋯ CBF and StiO2 reproducibly increased by controlled hypercapnia of up to 60 mmHg even during the period of the maximum expected vasospasm. The absence of a rebound effect within the first hour after hypercapnia indicates that an improvement of the protocol is possible. The intervention may yield a therapeutic potential to prevent ischemic deficits after aneurysmal SAH.