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Query: UMLS:C0268318 (ICP)
 10,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the cause of poor outcome in patients with normal pressure hydrocephalus (NPH) who did not respond as expected after shunt surgery. Two methods were used to evaluate shunts: radionuclide shunt patency study, or continuous ICP monitoring. 33/52 shunted patients (64%) from 1989 to 1995 had poor outcome, and 28/52 (54%) were investigated. Of those investigated, 9/28 (32%) were never better, and 19/28 (68%) were initially better then worse. Of 9 patients who were never better, ineffective shunt function was seen in 7; 5 had shunt revision (2 declined), and 1 improved. Of 19 patients who were initially better then worse, 15 had ineffective shunts; 15 underwent shunt revision, and 13 improved. Poor clinical outcome occurred in two-thirds of all patients after shunt surgery for NPH, but a potentially treatable cause (i.e. obstruction of the shunt or a shunt system that was patent but did not adequately correct the CSF circulatory disorder) was found in nearly 80% (22/28) of those investigated. The predominant cause of ineffective shunt function was obstruction of the peritoneal catheter. Clinical recovery occurred in 70% (14/20) of patients who had shunt revision surgery. We conclude that ineffective shunt function is a frequent cause of poor outcome after shunt surgery to treat NPH that should be sought and treated. These results have implications for longitudinal studies of the diagnosis and treatment of NPH. The effect of unrecognized shunt ineffectiveness on prior studies is unknown. Future studies should be designed to confirm that shunts are functioning before the diagnosis of NPH is considered incorrect.
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PMID:Evaluation of shunt function in patients who are never better, or better than worse after shunt surgery for NPH. 977 32

This study was carried out to elucidate the pathophysiologic mechanism of cerebral hyperemia observed during the early phase of bacterial meningitis. We tested the hypothesis that microbial invasion through the blood-brain barrier is responsible for cerebral vasodilation and hyperemia in meningitis. Escherichia coli was given either intravenously (i.v.) or intracisternally (i.c.) to closely mimic the primary or secondary bacterial invasion occurring in meningitis and newborn piglets were grouped according to their invasion results (+ or -); 12 in the i.v. (+) group, 14 in the i.v. (-) group, 13 in the i.c. (+) group, 15 in the i.c. (-) group. The results were compared with eight animals in the control group. Near infrared spectroscopy (NIRS) was employed to monitor changes in total hemoglobin (HbT), oxygenated hemoglobin (HbO), deoxygenated hemoglobin (Hb), deduced hemoglobin (HbD), and oxidized cytochrome aa3 (Cyt aa3). HbT, as an index of cerebral blood volume, increased progressively in both i.v. (+) and i.v. (-) groups and became significantly different from control and baseline values at 2 h. Hb significantly increased only in i.v. (+) group. HbD, as an index of cerebral blood flow, decreased significantly in i.v. (+), i.v.(-) and i.c. (-) groups and this change was mitigated in i.c. (+) group, HbO was reduced in i.c. (-) group and this decrease was attenuated in i.c. (+) group. Increased Cyt aa3 was observed in all experimental groups after bacterial inoculation. Changes in ICP, blood pressure, cerebral perfusion pressure, blood or CSF glucose or lactate, CSF TNF-alpha level, or CSF leukocytes number were not associated with changes in NIRS findings. These findings suggest that primary or secondary bacterial invasion across the blood-brain barrier is primarily responsible for cerebral vasodilation and hyperemia observed during the early phase of bacterial meningitis.
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PMID:Effects of microbial invasion on cerebral hemodynamics and oxygenation monitored by near infrared spectroscopy in experimental Escherichia coli meningitis in the newborn piglet. 1040 12

Previous studies have indicated that intraventricular administration of tissue-type plasminogen activator (TPA) might improve the prognosis of patients with intraventricular haemorrhage (IVH). In aneurysmal IVH, fibrinolytic treatment was always preceded by surgical repair of the aneurysm, since the risk of recurrent haemorrhage from a non-occluded aneurysm was estimated to be high. We reviewed a series of patients with IVH secondary to ruptured aneurysms (n = 4) or arteriovenous malformation (AVM; n = 1) who underwent emergency intraventricular administration of TPA before repair of the bleeding source. Fibrinolysis resulted in rapid decrease of haematoma volume and of ventricular dilatation, and prevented ventricular catheters from becoming obstructed. No intracranial haemorrhages or other complications occurred. The results suggest that the presence of recently ruptured aneurysms or AVM is not necessarily a contraindication for intraventricular administration of TPA. The potentially life saving benefits might outweigh the inherent risks of recurrent haemorrhage in carefully selected patients with massive IVH, in whom ventricular distension, periventricular brain compression, obstruction of CSF flow, and elevated ICP appear to be major determinants for the outcome.
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PMID:Fibrinolytic treatment of intraventricular haemorrhage preceding surgical repair of ruptured aneurysms and arteriovenous malformations. 1061 79

Computer-aided processing of the results obtained with the intrathecal infusion test using our newly developed mathematical model simplifies the investigation technique and thus the diagnosis of normal pressure hydrocephalus. Simultaneous determination of resistance and compliance in a single session markedly reduces the examination-related stress on the patient. In contrast to the classical methods, the new calculation does not require the ICP to reach a plateau. Unlike the static approach, our model describes the functional pressure-dependent course of the resistance. This means that account is taken of the non-linearity of the CSF dynamics during the processing of the biosignal. The intrathecal infusion test used to measure resistance and compliance is a reliable diagnostic method in patients with a normal pressure hydrocephalus.
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PMID:[Pressure-dependent flow resistance in craniospinal cerebrospinal fluid dynamics: a calculation model for diagnosis of normal pressure hydrocephalus]. 1072 Dec 34

Pseudotumor cerebri (PTC) presents with varied spectrum of manifestations, association with diverse pathological conditions and variable outcome. A preliminary observation on children presenting with PTC is being presented because of certain peculiarities, not observed earlier, like occurring in clusters during particular season, all were infants having close relationship with viral illness and all had extremely benign outcome. Children presenting with raised ICP were hospitalised and evaluated. The relevant investigations carried out included lumbar puncture, cranial ultrasonography, CT Scan and culture studies. Fifteen children, all in infancy with male-female ratio of 2:3 presented in clusters of 11 (73.3%) cases during late summer and early fall presented with bulging fontanelle, vomiting 11, fever 12, respiratory infection 5, diarrhea 5, lateral deviation of eye balls 4 and skin rashes 5 cases. Contact with viral illness in the family was found in 10 cases. Lumbar puncture showed high opening high CSF pressure in all. Results of this study suggest peculiar and perhaps different form of PTC seen recently which affected only the infants. These were closely related to viral illness and had benign outcome.
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PMID:Infantile pseudotumor cerebri related to viral illness. 1083 33

ICP monitoring per se has never been subjected to a prospective randomized clinical trial (PRCT) to establish its efficacy (or lack thereof) in improving outcome from severe head injury. Hence, there are insufficient data to support its use as a standard. However, there is a large body of published clinical experience that indicates that ICP monitoring (1) helps in the earlier detection of intracranial mass lesions, (2) can limit the indiscriminate use of therapies to control ICP which themselves can be potentially harmful, (3) can reduce ICP by CSF drainage and thus improve cerebral perfusion, (4) helps in determining prognosis, and (5) may improve outcome. ICP monitoring is therefore used by most head injury experts in the United States and is accepted as a relatively low-risk high-yield, modest cost intervention. Comatose head injury patients (GCS 3-8) with abnormal CT scans should undergo ICP monitoring. Comatose patients with normal CT scans have a much lower incidence of intracranial hypertension unless they have two or more of the following features at admission: age over 40, unilateral or bilateral motor posturing, or a systolic blood pressure of less than 90 mm Hg. ICP monitoring in patients with a normal CT scan with two or more of these risk factors is suggested as a guideline. Routine ICP monitoring is not indicated in patients with mild or moderate head injury. However, it may be undertaken in certain conscious patients with traumatic mass lesions at the discretion of the treating physician.
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PMID:The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Indications for intracranial pressure monitoring. 1093 90

In patients who require ICP monitoring, a ventricular catheter connected to an external strain gauge transducer or catheter tip pressure transducer device is the most accurate reliable method of monitoring ICP and enables therapeutic CSF drainage. Clinically significant infections or hemorrhage associated with ICP devices causing patient morbidity are rare and should not deter the decision to monitor ICP. Parenchymal catheter tip pressure transducer devices measure ICP similar to ventricular ICP pressure but have the potential for significant measurement differences and drift due to the inability to recalibrate. These devices are advantageous when ventricular ICP is not obtained or if there is obstruction in the fluid couple. Subarachnoid or subdural fluid coupled devices and epidural ICP devices are currently less accurate.
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PMID:The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Recommendations for intracranial pressure monitoring technology. 1093 92

Various methods of laboratory testing are currently being used to explore the hydrodynamic properties of shunts. We constructed a novel shunt-testing rig with a human-like compliance to be able to subject shunts to in-vivo recorded ICP patterns. The human-like situation was realized with a pear-shaped glass container with a non-linear, third-order pressure/volume characteristic similar to the CSF system. The new device also allows conventional shunt testing. Shunt performance in conventional pressure/flow tests (linear compliance) was compared to tests with human-like compliance. No clinically relevant differences were seen. Clinically recorded ICP waves (Lundberg type A and B) were reproduced before and after shunt implementation. Shunt insertion reduced pressure in the A-wave pattern to slightly negative values. Reproducing B-waves, the shunt dampened wave amplitude and pressure decreased below the opening pressure of the valve. In conclusion, the presented device allows a standardized reproduction of ICP patterns. The effects of shunt implantation can be studied.
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PMID:Application of clinically recorded ICP patterns--an extension of conventional shunt testing. 1115 1

The internationally accepted methods of calculating cerebrospinal fluid dynamics proceed from the assumption of a pressure-independent resistance to CSF outflow. Our new model focusses on the pressure-dependency of this resistance. In it, we monitor the entire pressure course over time, p(t) during and after infusion. A comparison of the pressure rise, On(p), during infusion, and the decrease, Off(p), to the same pressure level, permits the creation of all the formulas for C(p) and R(p). The simultaneous measurement of resistance and compliance during a single intervention allows us to minimize patient exertion. In contrast to the classical methods, it is not necessary for the ICP to reach a plateau. Our mathematical model differs from the static examination model by describing a pressure-dependent slope of the function for the resistance. This has been demonstrated in a study using H-Tx rats. In this way, we are able to take the non-linearity of the CSF resorption into consideration.
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PMID:[Pressure-dependent outflow resistance in cerebrospinal fluid dynamics: evaluation a calculation model for diagnosis of normal pressure hydrocephalus in an animal experiment with H-Tx rats]. 1138 39

Acute brain injury states (e.g. head injury, subarachnoid haemorrhage) show clear inverse relationships of ICP vs compliance, with ICP instability at times of lower compliance states. Variance in compliance values is large in hydrocephalus where ICP is relatively lower and compliance higher. Nonetheless, early experience shows that compliance data influence decisions on CSF diversion treatments. Future work will focus on the ability of intracranial compliance to predict ensuing ICP instability and methodological refinement for monitoring patients who have higher compliance states.
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PMID:Multi-centre assessment of the Spiegelberg compliance monitor: preliminary results. 1145 76


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