Neurocritical care
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This study assesses the utility of a hybrid optical instrument for noninvasive transcranial monitoring in the neurointensive care unit. The instrument is based on diffuse correlation spectroscopy (DCS) for measurement of cerebral blood flow (CBF), and near-infrared spectroscopy (NIRS) for measurement of oxy- and deoxy-hemoglobin concentration. DCS/NIRS measurements of CBF and oxygenation from frontal lobes are compared with concurrent xenon-enhanced computed tomography (XeCT) in patients during induced blood pressure changes and carbon dioxide arterial partial pressure variation. ⋯ DCS measurements of CBF and NIRS measurements of tissue blood oxygenation were successfully obtained in neurocritical care patients. The potential for DCS to provide continuous, noninvasive bedside monitoring for the purpose of CBF management and individualized care is demonstrated.
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Cardiac arrest and aneurysmal subarachnoid hemorrhage both cause sudden, severe cerebral hypoperfusion at ictus. Animal studies indicate that the resultant microvascular dysfunction and cerebral perfusion abnormalities are important determinants of the associated cerebral injury in both conditions. Although this suggests that perfusion imaging might be a useful tool for prognostication in patients with these conditions, this hypothesis has not been thoroughly investigated in humans. ⋯ Early global cerebral hypoperfusion can be demonstrated by CT perfusion imaging after cardiac arrest associated with high-grade aneurysmal subarachnoid hemorrhage and may be indicative of poor neurologic outcome. CT perfusion should be investigated as a prognostic tool in these conditions.
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We examined a bedside technique transcerebral double-indicator dilution (TCID) for global cerebral blood flow (CBF) as well as the concept of effective cerebral perfusion pressure (CPP(eff)) during different treatment options for intracranial hypertension, and compared global CBF and CPP(eff) with simultaneously obtained conventional parameters. ⋯ TCID allows repeated measurements of global CBF at the bedside. Elevated ventilation lowered and osmotherapy temporarily raised global CBF. In situations of increased vasotonus, CPP(eff) is a better indicator of blood flow changes than conventional CPP.
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Cerebral arterial vasospasm and delayed ischemic neurological deficits are significant contributors to morbidity and mortality following aneurysmal subarachnoid hemorrhage. Additional treatment modalities are needed. Intraventricular nicardipine has been suggested as a potential therapy for the treatment of cerebral vasospasm. It is an appealing option for multiple reasons: many of these patients already have ventricular drains in place, it can be safely administered at the bedside, and can be used in patients for whom conventional therapies are either not effective or not tolerated. ⋯ Intraventricular nicardipine was associated with a significant and sustained reduction in mean cerebral blood flow velocity as measured by transcranial Doppler when used in the treatment of suspected cerebral vasospasm following aneurysmal subarachnoid hemorrhage. We do not find significant safety concerns related to elevations of intracranial pressure or ventricular catheter related infections. Further prospective studies are warranted to better determine the efficacy and safety of this therapy.
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Intracerebral hemorrhage (ICH) is associated with the highest mortality of all strokes. Admission to a Neurosciences Critical Care Unit (NCCU) compared to a general ICU has been associated with reduced mortality following ICH. Such association has led to several hospitals transferring ICH patients to Neuro-ICUs in tertiary care centers. However, delays in optimizing ICH management prior to and during transfer can lead to deleterious consequences. To compare functional outcomes in ICH patients admitted to our NCCU directly from the ED versus inter-hospital transfer admissions. ⋯ Patients with ICH brought directly to our ED had significantly better outcomes than IHT; we hypothesize this may be caused by delays in optimizing management prior to arrival at the facility with a dedicated Neuro-ICU. Nevertheless, other equally plausible hypotheses need to be prospectively tested.