Neurocritical care
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The noise produced by oscillatory movements of secretions in the oropharynx, hypopharynx, and trachea during inspiration and expiration in unconscious terminal patients is often described as "the death rattle." The secretions are produced by the salivary glands and bronchial mucosa. These patients are usually too weak to expectorate or swallow the migrating secretions. Sputum usually only accumulates in these areas if there is a significant impairment of the cough reflex, as in deep coma or near death. ⋯ Death rattle was most commonly reported in patients dying from pulmonary malignancies, primary brain tumors, or brain metastases, and predicts death within 48 hours in 75% of the patients. After withdrawal of artificial ventilation from the intensive care unit, excessive respiratory secretion resulting in a rattling breathing during the last hours of life is not uncommon, especially not in pulmonary and neurological patients. The distressing experience and negative influence in the bereavement process indicates an ethical demand to treat this symptom from the perspective of others merely than that of the patient.
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The ideal therapy and neurocritical care for patients with aneurysmal subarachnoid hemorrhage (SAH) follows from an early and accurate diagnosis. However, approximately 30% of patients with SAH are misdiagnosed at their initial visit to a physician. ⋯ I suggest a strategy for selecting which patients with headache require evaluation beyond history and physical examination and how that evaluation should proceed. Other diagnostic issues are also discussed, such as use of magnetic resonance scanning and angiography for diagnosis, distinguishing the traumatic LP from true SAH, the concept of warning bleeds, and the LP-first diagnostic strategy.
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Review
Physiological and biochemical principles underlying volume-targeted therapy--the "Lund concept".
The optimal therapy of sustained increase in intracranial pressure (ICP) remains controversial. The volume-targeted therapy ("Lund concept") discussed in this article focuses on the physiological volume regulation of the intracranial compartments. The balance between effective transcapillary hydrostatic and osmotic pressures constitutes the driving force for transcapillary fluid exchange. ⋯ Pressure autoregulation of cerebral blood flow is likely to be impaired in these conditions. A high cerebral perfusion pressure accordingly increases intracapillary hydrostatic pressure and leads to increased intracerebral water content and an increase in ICP. The volume-targeted "Lund concept" has been evaluated in experimental and clinical studies to examine the physiological and biochemical (utilizing intracerebral microdialysis) effects, and the clinical experiences have been favorable.
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Cerebral vasospasm secondary to aneurysmal subarachnoid hemorrhage that has become refractory to maximal medical management can be treated with selective intra-arterial papaverine infusions. Papaverine is a potent vasodilator of the proximal, intermediate, and distal cerebral arteries and can improve cerebral blood flow (CBF). ⋯ Intra-arterial papaverine can be used alone or in combination with balloon angioplasty. This article reviews the mechanism of action, technique of administration, effects on CBF, clinical results, and complications of intra-arterial papaverine for the treatment of cerebral vasospasm.
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The value of brain tissue oxygenation (PbtO2) measurements in determining brain death is unknown. ⋯ PbtO2 can be successfully and accurately used as a bedside adjunctive test for brain death. The use of PbtO2 as a sole confirmatory test for brain death in the setting of an appropriate clinical examination will require the evaluation of a larger number of patients to assess its sensitivity and specificity.