An improved reservoir for the flushing test to diagnose shunt insufficiency.

OBJECTIVE Reservoirs integrated into hydrocephalus shunts are commonly used for the removal of CSF and for intra-ventricular pressure measurement. Pumping with the reservoir to diagnose shunt sufficiency is still a matter of controversy. The authors describe an improved flushing device and its characteristic features in vitro and in vivo. METHODS The flushing reservoir is constructed with a sapphire ball in a cage as a nonresistance valve to also enable the detection of distal occlusions. The most important reservoir parameters were investigated in vitro, simulating total and partial proximal and distal shunt occlusions. Then the expected advantages were assessed in vivo by evaluating the pump test data of 360 implanted reservoirs. The results were compared with those found in the literature. RESULTS The optimization of the technical parameters of the device, such as the high stroke volume in combination with moderate suction force, are obvious advantages compared with other flushing devices. Total occlusion of the ventricular catheter and the valve could be assessed with high certainty. The detection of a total obstruction of the peritoneal catheter or any partial obstruction is also possible, depending on its exact grade and location. CONCLUSIONS Shunt obstructions can be assessed using the pumping test. The reservoir construction presented here provides a clear enhancement of that diagnostic test.

Vestibulo-ocular monitoring as a predictor of outcome after severe traumatic brain injury.

INTRODUCTION: Based on the knowledge that traumatic brainstem damage often leads to alteration in brainstem functions, including the vestibulo-ocular reflex, the present study is designed to determine whether prediction of outcome in the early phase after severe traumatic brain injury is possible by means of vestibulo-ocular monitoring. METHODS: Vestibulo-ocular monitoring is based on video-oculographic recording of eye movements during galvanic labyrinth polarization. The integrity of vestibulo-ocular reflex is determined from the eye movement response during vestibular galvanic labyrinth polarization stimulation. Vestibulo-ocular monitoring is performed within three days after traumatic brain injury and the oculomotor response compared to outcome after six months (Glasgow Outcome Score). RESULTS: Twenty-seven patients underwent vestibulo-ocular monitoring within three days after severe traumatic brain injury. One patient was excluded from the study. In 16 patients oculomotor response was induced, in the remaining 11 patients no oculomotor response was observed. The patients' outcome was classified as Glasgow Outcome Score 1-2 or as Glasgow Outcome Score 3 to 5. Statistical testing supported the hypothesis that those patients with oculomotor response tended to recover (exact two-sided Fisher-Test (P < 10-3)). CONCLUSIONS: The results indicate that vestibulo-ocular monitoring with galvanic labyrinth polarization performed during the first days after traumatic brain injury helps to predict favourable or unfavourable outcome. As an indicator of brainstem function, vestibulo-ocular monitoring provides a useful, complementary approach to the identification of brainstem lesions by imaging techniques.

Evidence for vestibular processing in the caudal fastigial nucleus using vector addition.

BACKGROUND: While strong vestibular input to the fastigial nucleus has been demonstrated, little is known on how this is integrated in the oculomotor region of the caudal area of fastigial nucleus. In this study, single units in the caudal region of the fastigial nucleus were recorded in the rat, while applying sinusoidal galvanic stimuli to the labyrinths. MATERIAL/METHODS: The left and right labyrinths were polarized with either monaural or binaural sinusoidal stimuli (0.5 hertz), with stimulus phase shifts between right and left in 90 degrees steps (90 degrees, 180 degrees, 270 degrees, 360 degrees). The study describes the interaction and integration between the information of both labyrinths in the caudal fastigial nucleus. RESULTS: In 23 neurons, the relationship between input (galvanic stimuli to the labyrinths) and output (neuronal discharge) was analyzed for a series of stimuli (102 recordings in total). During monaural stimulation, phase shifts greater than 45 degrees were observed in 14 of 23 neurons (60.9%) during stimulation to the left and right labyrinths. To explain this phenomenon and the previously observed tuning characteristics in the fastigial nucleus, the neuronal responses were regarded as vectors. Thus, the observed response for binaural stimulation appeared to correspond to a vector addition of the left and right vestibular afferents. Of the 23 neurons, 14 neurons (60.9%) indicated a difference between predicted and measured values of less than 14.1 degrees. CONCLUSIONS: The findings support a working model based on vector addition of vestibular afferents in the caudal fastigial nucleus.

Transcranial Doppler ultrasound during galvanic labyrinth polarization depicts central vestibular processing, demonstrating bilateral vestibular projection.

The combination of galvanic labyrinth polarization and transcranial Doppler ultrasound was employed to depict the neurovascular coupling in the cerebral vestibular areas. For galvanic stimulation, surface electrodes were attached to the right and left mastoid and two further electrodes were fixed near to each shoulder blade. Thus, each pair of electrodes (mastoid to shoulder) facilitated unilateral stimulation of the ipsilateral vestibular labyrinth. Blood flow in the middle cerebral artery and the internal carotid artery in both hemispheres was measured by means of Doppler ultrasound. The transcranial Doppler ultrasound system was head-fixed and allowed continuous monitoring of the blood flow throughout the trials. Using a series of different stimulation modes (bilateral, unilateral left, unilateral right and sham), the changes in mean blood flow velocity were evaluated by comparing baseline blood flow under resting conditions to blood flow during stimulation. A total of 18 trials were performed with each of seven volunteer subjects. Galvanic labyrinth polarization elicited a clear sensation of pendular body movement in all subjects. Significant blood flow increase (P < 0.05) in both hemispheres was observed during bilateral stimulation. Of more interest is that unilateral stimulation also elicited a significant increase in flow in both the ipsilateral and the contralateral hemispheres, demonstrating the existence of bilateral projections from each vestibular labyrinth. The combination of galvanic labyrinth polarization with transcranial Doppler ultrasound blood flow measurement provides a novel approach to the functional assessment of the vestibular system (deep cerebral structures and cortical areas). This novel technique provides a useful tool for clinical examinations.

Point-of-care testing for interleukin-6 in cerebro spinal fluid (CSF) after subarachnoid haemorrhage.

BACKGROUND: Intrathecal interleukin (IL)-6 is considered to be a proinflammatory biomarker for cerebral inflammatory response. This is of clinical importance for the prediction of vasospasm after subarachnoid haemorrhage (SAH). We evaluated a bedside technique for the quantitative measurement of IL-6 in the cerebrospinal fluid (CSF). MATERIAL/METHODS: 32 samples of CSF and serum were taken from 11 patients suffering from SAH on day 3, 4 and 5 after bleeding. A lateral flow immunoassay chip-test (POC-Test) was used for bedside testing and the results were compared to the standard chemiluminescence-based ELISA (Immulite) performed in a specialized laboratory. RESULTS: For CSF analysis Immulite and POC-Test show linear correlation (r2=0.81). The high IL-6 values found in SAH are depicted more easily by the POC-Test, because it has a working range of up to 10.000 pg/ml instead of up to 1000 pg/ml for Immulite. Serum IL-6 values were clearly lower, suggesting CNS inflammation in SAH. CONCLUSIONS: The new chip-test provides a handy tool for the neurosurgical intensive care unit, analysing CSF IL-6 concentrations within 20 minutes. This is the first time a point-of care test for IL-6 in CSF was evaluated. The test results match the values achieved by the standard Immulite technique. Therefore a tool for clinical routine interleukin-6 investigation is provided which could find use in a broad variety of neurosurgical and neurological diseases.

A new qualitative interleukin-6 bedside test can predict pneumonia in patients with severe head injury--comparison to the standard Immulite test and a semiquantitative bedside test.

Severe head injury (SHI) leads to systemic immunosuppression, which is processed by central mechanisms and is associated with a high risk of pneumonia. The timely identification of an immunodepressed condition in SHI patients might help prevent infections by changing the intensive care strategy. The aim of this prospective study is to evaluate a new method for identifying immunodepression and predicting pneumonia. We correlated interleukin (IL)-6 levels determined by the standard test (Immulite) and performed by specialized laboratories with those obtained using the new bedside test (PicoScan) with the occurrence of pneumonia in patients with SHI. Thirty-two patients with isolated SHI were investigated. Analyses were performed on serum samples taken 2 to 24 hours after trauma. Pearson correlation coefficient was 0.924 (P<0.001) for IL-6 values determined by PicoScan versus Immulite and Spearman rho was 0.572 for visual interpretation versus Immulite (P=0.01). Immulite and PicoScan have a positive predictive value of 91% and 100%, respectively, and a negative predictive value of 76% and 86%. The present study investigated for the first time the determination of IL-6 concentrations by PicoScan in patients. Our findings show a good correlation with the results of the standard Immulite test and suggest that the PicoScan may be used as a handy tool to predict pneumonia in SHI patients.

Using video-oculography for galvanic evoked vestibulo-ocular monitoring in comatose patients.

Binocular eye movement responses to galvanic vestibular stimulation were measured in comatose patients. Healthy persons have been demonstrated to show a consistent and reproducible relationship between eye movement and galvanic vestibular stimulation. Any pathology of the vestibular integrating structures (brainstem and to some degree the cerebellum and cortex) is assumed to influence this response pathognomonically. A monitoring facility was designed to record eye movements during galvanic labyrinth polarization (GaLa) in order to examine the vestibular response in comatose patients. GaLa was applied by means of two pairs of electrodes attached between the mastoid and interscapular region. A custom-built, battery-driven current-source stimulator served to generate sinusoidal stimuli that could be applied either unilaterally or simultaneously and independently to the left and right labyrinths. The resultant binocular eye movements were recorded using a Chronos Eye Tracker and the digital image sequences stored for subsequent analysis. Repeated testing was performed in five comatose patients with a Glasgow Coma Score of 3, who were intubated and ventilated (subarachnoid hemorrhage (n = 3), traumatic injury (n = 2)). The observed ocular movements varied. In four cases ocular movements in response to GaLa were observed, while one patient showed neither spontaneous nor galvanic-induced eye movements. The latter was diagnosed as brain-dead 2 days after testing. In contrast, the patients who showed ocular movements synchronous with galvanic stimulation left the intensive care unit (ICU) for rehabilitation. These data indicate that it is possible to assess brain function in comatose patients by evaluating the vestibulo-ocular response to galvanic stimulation. The designed monitoring facility can be used on the ICU ward without disconnection of other monitoring equipment.

Multiple cerebral aneurysms and subarachnoid hemorrhage in a patient with Alagille syndrome.

Although intracranial hemorrhage has frequently been found responsible for mortality in adult patients with Alagille syndrome (AGS), no specific underlying cause has been identified. We describe the case of severe subarachnoid hemorrhage in a 30-year-old woman harboring five intracranial aneurysms and multiple peripheral vascular anomalies. To evaluate a possible higher incidence of intracranial aneurysms, a study of the cerebral vasculature in all AGS patients by using noninvasive imaging techniques should be considered.

Reduction of shunt obstructions by using a peel-away sheath technique? A multicenter prospective randomized trial.

OBJECTIVE: Shunt obstructions may partly be caused by brain debris, which intrude into the ventricular catheter during ventricle puncture. Avoiding contact between the catheter and brain tissue, by using a peel-away sheath, should reduce the number of shunt failures caused by obstruction. To test this hypothesis, we conducted a randomized, prospective multicenter study. METHODS: 201 patients from 6 different neurosurgical centers in Germany receiving a ventriculo-peritoneal shunt were included in this study. Of these, 177 patients completed a 1-year follow-up period. Surgery was randomized in a 1 to 1 fashion, such that out of 177 procedures, 91 were performed using a peel-away sheath and 86 were performed without. The rate of surgical re-interventions and shunt obstructions within a 12-month period was recorded. RESULTS: Within 1 year post-surgery, 17 shunt obstructions (9.6%) leading to shunt revisions were recorded. However, no difference was found between surgeries performed using a peel-away sheath (9.9%) or not (9.3%). The overall shunt infection rate was 2.8% and the shunt revision rate for overdrainage was 3.9%. CONCLUSIONS: The theoretical advantages attributed to the use of a peel-away sheath to introduce a ventricular catheter could not be confirmed in this randomized study, suggesting that the proposed role of brain debris in shunt obstructions may be overestimated.

The adjustable proGAV shunt: a prospective safety and reliability multicenter study.

OBJECTIVE: To evaluate the reliability of the gravitation-assisted adjustable proGAV shunt system with a prospective multicenter study conducted in 10 German hospitals. METHODS: Enrollment for this observational study began in April 2005 and concluded in February 2006. The protocol required re-examinations 3 and 6 months postoperatively and fixed the endpoint of follow-up at 12 months after implantation. Patients with different types of adult, juvenile, and pediatric hydrocephalus were included and 165 patients were enrolled; 9 died and 12 had incomplete follow-up. RESULTS: Of the assessable 144 patients, 130 completed the protocol after 12 months, whereas 14 failed because of the need to explant the device, mainly because of infection. In 12 patients, components of the shunt, not the valve, were revised. In 65 of the 144 patients, there were 102 readjustments of the valve in 67 incidences because of underdrainage and in 35 because of overdrainage. In 1 case, readjustment was not possible. Determination of pressure level with the verification instrument was safe and corresponded to the required x-ray controls after adjustments. No unintended readjustments were noted. CONCLUSION: The proGAV is a safe and reliable device.

Interleukin-6 serum level assessment using a new qualitative point-of-care test in sepsis: A comparison with ELISA measurements.

OBJECTIVES: Interleukin-6 (IL-6) is involved in inflammatory diseases, provides prognostical information, and allows the early identification and monitoring of septic patients. We investigated whether IL-6 can be assessed using a new densitometric point-of-care (POC) bedside assay. DESIGN AND METHODS: 392 samples were prospectively collected from 57 intensive care unit patients (38 male, age: 45.2 +/- 16.9years, APACHE II score: 25.4 +/- 4.8). Blinded IL-6 measurements were performed using conventional semiautomatic enzyme-linked immunosorbent assays (ELISA) and the POC test. RESULTS: Mean IL-6 levels were 102.9 +/- 388.6pg/mL (ELISA) and 97.0 +/- 535.5 (POC). A significant correlation was found (p < 0.0001, r = 0.92). The sensitivity/specificity for sepsis was 82.6%/86.5% (ELISA, AUC: 0.881), and 76.4%/95.0% (POC, AUC: 0.868). CONCLUSIONS: Here we demonstrate significant correlations of IL-6 levels determined using a POC test and semiautomatic ELISA. ROC analyses revealed no significant differences between the two tests. With a turn-around time of 20min, the bedside IL-6 test is a new tool that may help to initiate early goal-directed therapy.