Critical care clinics
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Osmotherapy with compounds such as mannitol has become a mainstay of neurologic and neurosurgical intensive care. Elevated intracranial pressure is the most common indication. A substantive debate remains as to the appropriate timing of administration and the optimal fluid management protocol, and experts disagree about the clinically relevant mechanisms of action of osmotic diuretics. This article briefly summarizes the basic literature on the physical actions of mannitol, addresses commonly asked questions, and highlights some of the controversies that arise at the bedside.
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Critical care clinics · Jan 1997
ReviewMonitoring of cerebral hemodynamics with jugular bulb catheters.
Jugular venous oxygen saturation (SjvO2) monitoring is useful for detecting episodes of cerebral hypoxia/ischemia in patients with head injury, patients undergoing neurosurgical procedures, and patients undergoing cardiopulmonary bypass. The use of SjvO2 monitoring can direct the treatment of ischemic episodes and identify the optimal level of cerebral perfusion pressure and PCO2 for the individual patient.
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Generalised convulsive status epilepticus is a medical emergency. Knowledge of the pathophysiology of status epilepticus and the pharmacology of the medications used to treat it allow one to devise a rational protocol for management. Anticipation of medical complications facilitates intervention when required. Prognosis depends largely on the underlying causes.
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Critical care clinics · Jan 1997
ReviewThe use of hyperventilation and its impact on cerebral ischemia in the treatment of traumatic brain injury.
Traumatic brain injury is a common occurrence in the United States, leading to approximately 190,000 deaths or long-term disabilities. Following the primary insult, secondary disturbances in cerebral blood flow (CBF) and metabolism may have deleterious effects on potentially viable neurons. ⋯ Aggressive hyperventilation produces a marked reduction in CBF, which may give rise to or exacerbate cerebral ischemia, thus enhancing rather than reducing secondary injury. This article reviews the role of hyperventilation in the treatment of increased ICP and its impact on cerebral ischemia following traumatic brain injury.
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Critical care clinics · Jan 1997
ReviewTranscranial Doppler ultrasonography in the neurocritical care unit.
TCD ultrasonography is a noninvasive means to study the cerebral vasculature. By varying the depth and angle of insonation of a pulsed sound wave, the direction and velocity profile of the cerebral arteries can be ascertained. This can be used to identify areas of focal stenosis and increased resistance and to estimate the adequacy of cerebral flow. ⋯ TCD ultrasonography is capable of studying dynamic cerebrovascular processes. By being able to determine vessel patency, TCD may become a useful adjuvant to thrombolytic therapy. Continuous monitoring of flow velocities and profiles along with testing to cerebrovascular reserve promises to be a future active area of research.