Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2016
Is Impaired Autoregulation Associated with Mortality in Patients with Severe Cerebral Diseases?
Cerebral autoregulation (CA) is a mechanism that compensates for variations in cerebral perfusion pressure (CPP) by changes in cerebral blood flow resistance to keep the cerebral blood flow constant. In this study, the relationship between lethal outcome during hospitalisation and the autoregulation-related indices PRx and Mx was investigated. ⋯ Increased PRx and Mx were associated with risk of death in patients with severe cerebral diseases. The relationship with mortality was more pronounced in PRx, whereas Mx showed a better correlation with GOS score.
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Acta Neurochir. Suppl. · Jan 2016
Cerebral Arterial Time Constant Recorded from the MCA and PICA in Normal Subjects.
Cerebral arterial time constant (τ) estimates how quickly the cerebral arterial bed distal to the point of insonation is filled with arterial blood following a cardiac contraction. It is not known how τ behaves in different vascular territories in the brain. We therefore investigated the differences in τ of two cerebral arteries: the posterior inferior cerebellar artery (PICA) and the middle cerebral artery (MCA). ⋯ The MCA-supplied vascular bed has a longer distal average length, measured from the place of insonation up to the small arterioles, than the PICA-supplied vascular bed. Therefore, a longer time is needed to fill it with arterial blood volume. This study thus confirms the physiological validity of the τ concept.
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Acta Neurochir. Suppl. · Jan 2016
The Evolution of the Clinical Use of Osmotic Therapy in the Treatment of Cerebral Edema.
For almost a century, it has been known that hypertonic solutions shrink cerebral tissue. Early attempts used hypertonic solutions of ions (sodium, magnesium) and sugars (glucose, dextrose, sucrose), concentrated albumin, and, later, urea. These early attempts were largely abandoned because the effect was short lived and often followed by a period of rebound edema. ⋯ In the 1990s, use of hypertonic saline was reintroduced as an alternative to address concerns about mannitol. More recently, administration of hypertonic saline has transitioned from boluses to continuous infusions. The rationale for and data supporting the use of continuous infusions are presented.
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Acta Neurochir. Suppl. · Jan 2016
Effects of Brain Temperature on Cerebrovascular Autoregulation During the Acute Stage of Severe Traumatic Brain Injury.
The pressure reactivity index (PRx) is calculated as a moving correlation coefficient between intracranial pressure (ICP) and mean arterial blood pressure (MABP), and this analytical value is viewed as reflecting a vasomotor response to MABP variability. At present, the factors influencing the PRx value during the acute stage of traumatic brain injury (TBI) are not known. We observed significant cases where changes in the calculated value of PRx seemed to be influenced by changes in brain temperature during the course of acute stage TBI. ⋯ During the hypothermic condition, the mean value of PRx was -0.019; however, after gradual rewarming, the value of PRx increased drastically, and the mean value during the rewarming period, when the brain temperature exceeded 35 °C, was 0.331. Similarly, in another case where the patient underwent therapeutic brain hypothermia, the PRx showed a mean value of -0.038 during the hypothermic condition, and a mean value of 0.052 during the rewarming period. In both cases, a trend toward a negative correlation between ICP and MABP during brain hypothermia shifted to a positive correlation upon rewarming.
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Acta Neurochir. Suppl. · Jan 2016
CSF Lumbar Drainage: A Safe Surgical Option in Refractory Intracranial Hypertension Associated with Acute Posttraumatic External Hydrocephalus.
External lumbar drainage (ELD) of cerebrospinal fluid (CSF) in posttraumatic refractory intracranial hypertension (ICHT) is controversial. We report our experience of ELD in ICHT associated with acute disturbance of CSF flow within subarachnoid spaces (SASs). ⋯ Acute traumatic external hydrocephalus may explain some of the specific situations of secondary increased ICP, with a "normal" CT scan, that is refractory to medical treatment. In these situations, lumbar drainage should be considered to be a safe, minimally invasive, and effective surgical option.