Intracranial pressure

Pressures, Flow, and Brain Oxygenation During Plateau Waves of Intracranial Pressure

Authors: Dias C, Maia I, Cerejo A, Varsos G, Smielewski P, Paiva JA, Czosnyka M.

BACKGROUND: Plateau waves are common in traumatic brain injury. They constitute abrupt increases of intracranial pressure (ICP) above 40 mmHg associated with a decrease in cerebral perfusion pressure (CPP). The aim of this study was to describe plateau waves characteristics with multimodal brain monitoring in head injured patients admitted in neurocritical care.
METHODS: Prospective observational study in 18 multiple trauma patients with head injury admitted to Neurocritical Care Unit of Hospital Sao Joao in Porto. Multimodal systemic and brain monitoring of primary variables and secondary variables related to cerebral compensatory reserve and cerebrovascular reactivity were supported by dedicated software ICM+ ( www.neurosurg.cam.ac.uk/icmplus) . The compiled data were analyzed in patients who developed plateau waves.
RESULTS: In this study we identified 59 plateau waves that occurred in 44 % of the patients (8/18). During plateau waves CBF, cerebrovascular resistance, CO, and brain tissue oxygenation decreased. The duration and magnitude of plateau waves were greater in patients with working cerebrovascular reactivity. After the end of plateau wave, a hyperemic response was recorded in 64 % of cases with increase in CBF and brain oxygenation. The magnitude of hyperemia was associated with better autoregulation status and low oxygenation levels at baseline.
CONCLUSIONS: Multimodal brain monitoring facilitates identification and understanding of intrinsic vascular brain phenomenon, such as plateau waves, and may help the adequate management of acute head injury at bed side.

Therapeutic Hypothermia With the Use of Intracranial Pressure Monitoring for Acute Disseminated Encephalomyelitis With Brainstem Lesion: A Case Report

Authors: Miyamoto K, Kozu S, Arakawa A, Tsuboi T, Hirao JI, Ono K, Arisaka O.

Acute disseminated encephalomyelitis confined to the brainstem is associated with poor prognosis. We describe a case of a 10-year-old boy with acute disseminated encephalomyelitis in the brainstem that developed after influenza A infection. A 10-year-old boy presented with fever and prolonged disturbance of consciousness and was admitted to our hospital. Magnetic resonance imaging (MRI) of the midbrain, with T2-weighted and fluid-attenuated inversion recovery images, suggested acute disseminated encephalomyelitis accompanied by a brainstem lesion. Lumbar puncture showed pleocytosis and increased protein content, including myelin basic protein, interleukin-6, and immunoglobulin G, all suggestive of acute disseminated encephalomyelitis. Treatments such as methylprednisolone pulse therapy, intravenous immunoglobulin, and therapeutic hypothermia were performed. Although the patient presented with anisocoria with increased intracranial pressure monitoring during hypothermia, prompt therapy with d-mannitol and dopamine was effective. Our case results suggest that hypothermia could be included in the choice of therapy for acute disseminated encephalomyelitis with brainstem lesions.

Increased intracranial pressure and brain edema

Authors: Dietrich W, Erbguth F.

In primary and secondary brain diseases, increasing volumes of the three compartments of brain tissue, cerebrospinal fluid, or blood lead to a critical increase in intracranial pressure (ICP). A rising ICP is associated with typical clinical symptoms; however, during analgosedation it can only be detected by invasive ICP monitoring. Other neuromonitoring procedures are not as effective as ICP monitoring; they reflect the ICP changes and their complications by other metabolic and oxygenation parameters. The most relevant parameter for brain perfusion is cerebral perfusion pressure (CPP), which is calculated as the difference between the middle arterial pressure (MAP) and the ICP. A mixed body of evidence exists for the different ICP-reducing treatment measures, such as hyperventilation, hyperosmolar substances, hypothermia, glucocorticosteroids, CSF drainage, and decompressive surgery.

Valsalva manoeuver, intra-ocular pressure, cerebrospinal fluid pressure, optic disc topography: Beijing intracranial and intra-ocular pressure study

Authors: Zhang Z, Wang X, Jonas JB, Wang H, Zhang X, Peng X, Ritch R, Tian G, Yang D, Li L, Li J, Wang N.

PURPOSE: To assess whether a Valsalva manoeuver influences intra-ocular pressure (IOP), cerebrospinal fluid pressure (CSF-P) and, by a change in the trans-laminar cribrosa pressure difference, optic nerve head morphology.
METHODS: In the first part of the study, 20 neurological patients (study group 'A') underwent measurement of IOP and lumbar CSF-P measurement in a lying position before and during a Valsalva manoeuver. In the second study part, 20 healthy subjects (study group 'B') underwent ocular tonometry and confocal scanning laser tomography of the optic nerve head before and during a Valsalva manoeuver.
RESULTS: During the Valsalva manoeuver in study group 'A', the increase in CSF-P by 10.5 ± 2.7 mmHg was significantly (p < 0.001) higher than the increase in IOP by 1.9 ± 2.4 mmHg. The change in CSF-P was not significantly (p = 0.61) correlated with the change in IOP. During the Valsalva manoeuver in study group 'B', IOP increased by 4.5 ± 4.2 mmHg and optic cup volume (p < 0.001), cup/disc area ratio (p = 0.02), cup/disc diameter ratio (p = 0.03) and maximum optic cup depth (p = 0.01) significantly decreased, while neuroretinal rim volume (p = 0.005) and mean retinal nerve fibre layer thickness (p = 0.02) significantly increased.
CONCLUSIONS: The Valsalva manoeuver-associated short-term increase in CSF-P was significantly larger than a simultaneous short-term increase in IOP. It led to a Valsalva manoeuver-associated decrease or reversal of the trans-laminar cribrosa pressure difference, which was associated with a change in the three-dimensional optic nerve head morphology: optic cup-related parameters decreased and neuroretinal rim-related parameters enlarged. These findings may be of interest for the pathogenesis of glaucomatous optic neuropathy.

Short-duration hypothermia after ischemic stroke prevents delayed intracranial pressure rise

Authors: Murtha LA, McLeod DD, McCann SK, Pepperall D, Chung S, Levi CR, Calford MB, Spratt NJ.

BACKGROUND: Intracranial pressure elevation, peaking three to seven post-stroke is well recognized following large strokes. Data following small-moderate stroke are limited. Therapeutic hypothermia improves outcome after cardiac arrest, is strongly neuroprotective in experimental stroke, and is under clinical trial in stroke. Hypothermia lowers elevated intracranial pressure; however, rebound intracranial pressure elevation and neurological deterioration may occur during rewarming.
HYPOTHESES: (1) Intracranial pressure increases 24 h after moderate and small strokes. (2) Short-duration hypothermia-rewarming, instituted before intracranial pressure elevation, prevents this 24 h intracranial pressure elevation.

MRI findings of elevated intracranial pressure in cerebral venous thrombosis versus idiopathic intracranial hypertension with transverse sinus stenosis

Authors: Ridha MA, Saindane AM, Bruce BB, Riggeal BD, Kelly LP, Newman NJ, Biousse V.

PURPOSE: To determine whether MRI signs suggesting elevated intracranial pressure (ICP) are preferentially found in patients with idiopathic intracranial hypertension (IIH) than in those with cerebral venous thrombosis (CVT).
METHODS: Among 240 patients who underwent standardized contrast-enhanced brain MRI/MRV at our institution between 9/2009 and 9/2011, 60 with abnormal imaging findings on MRV were included: 27 patients with definite IIH, 2 patients with presumed IIH, and 31 with definite CVT. Medical records were reviewed, and imaging studies were prospectively evaluated by the same neuroradiologist to assess for presence or absence of transverse sinus stenosis (TSS), site of CVT if present, posterior globe flattening, optic nerve sheath dilation/tortuosity, and the size/appearance of the sella turcica.
RESULTS: 29 IIH patients (28 women, 19 black, median-age 28, median-body mass index, 34) had bilateral TSS. 31 CVT patients (19 women, 13 black, median-age 46, median-BMI 29) had thrombosis of the sagittal (3), sigmoid (3), cavernous (1), unilateral transverse (7), or multiple (16) sinuses or cortical veins (1). Empty/partially-empty sellae were more common in IIH (3/29 and 24/29) than in CVT patients (1/31 and 19/31) (p<0.001). Flattening of the globes and dilation/tortuosity of the optic nerve sheaths were more common in IIH (20/29 and 18/29) than in CVT patients (13/31 and 5/31) (p<0.04).
CONCLUSION: Although abnormal imaging findings suggestive of raised ICP are more common in IIH, they are not specific for IIH and are found in patients with raised ICP from other causes such as CVT.

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