Eckhard Rickels

Treatment of Elevated Intracranial Pressure by Infusions of 10% Saline in Severely Head Injured Patients

The management of intracranial pressure (ICP) is a factor in outcome of patients with head trauma. However, recent studies have revealed that the current strategies, which have been applied to control ICP for adequate cerebral perfusion, are unsatisfactory. Against this background, the efficacy of short-term infusions of hypertonic saline on ICP was investigated. In severely head injured (SHI) patients, hypertonic saline (100 ml 10% NaCl) was administered when standard agents (mannitol, sorbitol, THAM) failed in reducing ICP. To evaluate the pressure reduction after saline infusions the resulting ICP relaxations were analysed statistically in respect to the parameters amplitude, duration and dynamic behaviour of the ICP responses. In 42 randomized relaxations, the relative ICP decrease was 43% [28%-58%] (median [interquartile range]). The corresponding pressure drop was 18 mmHg [15-27 mm Hg]. Relaxations lasted for 93 min [64-126 min] and a relative ICP minimum was reached 26 min [12-33 min] after infusion. In the individual cases the temporal course of the parameters amplitude and decline interval depict a tendency toward lower and higher values, respectively, under conditions of a generally increasing ICP. As expected, the infusion of hypertonic saline reduces ICP in patients suffering from SHI. The pressure drop, duration and dynamic behaviour are suspected to depend both on the pressure level to reduce and concomitant medications.

Head Trauma in Children, Part 3: Clinical and Psychosocial Outcome After Head Trauma in Children

With the aim of determining long-term outcome, the authors approached 38 families (average 2.1 years after trauma) with a questionnaire, following the acute-clinical treatment of head trauma of their children. Long-term damage was restricted almost exclusively to patients presenting with a Glasgow Coma Score ≤8. Paresis (16%), cranial nerve damage (13%), incontinence (5%), or coordinative disturbances (18%) continued. The older children stated that they influenced their life to a great extent (11%). Furthermore, many had mental and cognitive problems that occur quite frequently even in children with light head trauma and often only manifest after release from hospital. This causes problems and results in inferior performance (26%), especially at school, which is further complicated through lengthy periods of absence. The parents, especially, mentioned behavioral problems such as social withdrawal or aggressive demeanor, which led to tension also inside the family. A persistent vegetative state is rare after head trauma in children.

Health-Related Quality of Life After Spontaneous Subarachnoid Hemorrhage Measured in a Recent Patient Population

OBJECTIVE This study sought to determine the impact of spontaneous subarachnoid hemorrhage (SAH) on health-related quality of life (HRQOL). METHODS Data were taken retrospectively from 601 patients (219 male, 382 female) treated between 1998 and 2008. Questionnaires concerning HRQOL were circulated prospectively, and the responses from 253 patients (81 male, 172 female) were analyzed. The questionnaires comprised the standardized Short-Form 36 (SF-36) and Short-Form 12 (SF-12) Health Surveys, a number of nonstandardized questions, and visual analogue scales. Statistical analysis of the results was exploratory, using unifactorial ANOVA (Scheffe), multivariate analyses of variance. RESULTS The HRQOL is reduced considerably by SAH and remains so for a period of 10 years. Physical and emotional domains are primarily affected, but also cognitive functions, including memory and concentration in particular. Similarly, certain roles are affected that prove difficult to rehabilitate after acute care and cause serious debility in the long term. The Hunt and Hess Scale, Glasgow Outcome Scale, and seizures were found to have the greatest impact on HRQOL. CONCLUSIONS Documentation of HRQOL after 6 to 12 months is useful because patients are often found to have a diminished HRQOL in the absence of a clear physical impairment. Because psychological, emotional, cognitive, and social functioning influence HRQOL in the long term, efforts at rehabilitation should focus in particular on improving such factors. Documentation of HRQOL is a useful, additive tool for consolidating and evaluating the outcome, and a treatment end point after SAH, respectively.

The use of recombinant activated factor VII in neurosurgery

BACKGROUND Bleeding complications in neurosurgery often take alarming proportions without major hemodynamic effect or impairment of coagulation physiology because severe neurologic deficits are to be expected. Any measures used to stabilize or normalize coagulation are therefore of great interest. Administration of packed red cells, fresh frozen plasma, and platelet concentrates is associated with volume loading, which is suspected to multiply the secondary brain damage, for example, by the development of an edema. In this respect, the administration of rFVIIa may develop into a new option associated with low-volume administration. CASE DESCRIPTIONS We report on 5 neurosurgical patients to whom rFVIIa was given at doses of 51 to 202 microg/kg of body weight for the treatment of severe intraoperative bleeding (n = 3) or as prophylaxis of bleeding (n = 2). The operation was completed successfully in all patients after administration of rFVIIa, with stabilization of the coagulation status. CONCLUSION Therefore, reported cases constitute an approach in treatment and prophylaxis of bleeding complications in neurosurgery. There are reports of thromboembolic events in use of rFVIIa, particularly in unlabeled use. But according to our findings and current literature, there is no evidence of higher risk of thromboembolic adverse events in treatment with rFVIIa. However, the number of patients presented does not allow any final assessment to be made as to whether the properties of rFVIIa are of particular benefit for neurosurgical patients. Further studies with appropriate study design are required to verify effects observed in this investigation.

Correct Measurement of Cerebral Perfusion Pressure (CPP)

For the monitoring of patients with intracranial mass lesions, the measurement of intracranial pressure (ICP) is an essential parameter. Therapy of brain swelling, indication for CT or even neurosurgical operations are often based on the us of the ICP. In addition, using arterial pressure (AP), the cerebral perfusion pressure (CPP) can be calculated (CPP = AP-ICP). CPP is important in considering extracranial factors, such as changes in blood volume or arterial pressure, resulting in secondary brain swelling and ischemia. In contrast to ICP monitoring, where hydrostatic level is easily standardized to the foramen of Monro, there exist various methods of measuring AP. It is usually not registered at the level of skull base, but in peripheral arteries with structural and functional differences (Gauer 1965). Previous investigations on CPP used varying mathematical methods for calculation of the mean arterial pressure, and the optimal grade of head elevation in intracranial hypertension is still under discussion.

Assessment of Cerebral Blood Flow by Means of Blood-Flow-Volume Measurement

To the Editor: With great interest we read in Stroke that a working group around Soustiel1 compared cerebral blood flow (CBF) as measured by 133xenon clearance technique with blood-flow-volume (BFV) measurements from the internal carotid artery (ICA). Soustiel et al found well-correlated …

Stationarity in Neuromonitoring Data

PURPOSE Signals reflecting the metabolic and circulatory status of an injured central nervous system are normally corrupted systematically. The patient is part of a therapeutic control-loop and the signals acquired are rather determined by the quality of control (stationarity of signals) than by the underlying pathological process. METHODS To verify the control-loop hypothesis, neuromonitoring data from 12 randomly selected severely head injured patients (initial GCS ≤ 8, 7 men, 5 women) were analysed for circulatory (blood pressure, intracranial pressure [ICP], cerebral perfusion pressure [CPP]) and metabolic (arterial blood gases, jugular bulb oxygenation [SjvO(2)], brain tissue oxygen partial pressure [ptiO(2)]) variables (n = 10). A total of 120 time series of generally not equidistant sample intervals were assessed for stationarity by Wallis & Moores runs test. RESULTS Non-stationarity could only be proven in 23 time series, i.e. the control-loop hypothesis was violated. Trends were mainly found in CPP (n = 5) and ICP (n = 4). The remaining cases spread out on all but one (temperature) signal. Nine patients showed at least one time series with a trend. One patient had clear trends in five out of ten variables that focused on SjvO(2), ptiO(2), ICP and CPP. CONCLUSIONS Absence of stationarity in about 20% of time series is credited to an effective therapeutic control-loop. For analytical purposes, however, the benefit seems to be overestimated. Consequently, neuromonitoring should be considered the analysis of short-term disturbances that are intentionally compensated for by a short response time. Information content is thus reduced even if the number of sensor devices increases.

Analysis of Intracranial Pressure Time Series Using Wavelets (Haar Basis Functions)

PURPOSE Transforming intracranial pressure (ICP) into frequency domain commenced in the early 1980s, arriving at the conclusion that cerebrospinal dynamics were mapped by ICP spectral composition. Classical analysis tools were not suitable for handling intrinsic signal non-stationarity. To overcome inherent obstacles we introduce a novel approach based upon wavelets. METHODS During routine diagnostic volume pressure testing epidural ICP was acquired in 118 patients with suspected cerebrospinal fluid circulatory disorders. Pressure was digitised and conditioned to separate low frequent signal components (<heart rate). ICP fluctuations were computed by subtraction of original and low frequent ICP constituents. Subsequently, multiresolution analysis was performed on fluctuations by discrete Haar wavelet transform and coefficients displayed in dyadic fashion (scalogram). RESULTS Decomposition of ICP fluctuations led to typical patterns in the scalogram. Episodes of pathological wave activity and artificial ICP changes were topographically detectable in the time frequency plane. CONCLUSIONS The wavelet approach is a simple yet powerful signal processing method to estimate both static and dynamic properties of ICP in various clinical scenarios. It therefore outclasses classical spectral transforms that are limited to analysing real-world data. Haar wavelets are fast and robust. Their disadvantages seem not to counterbalance the advantages in this biomedical application.

Cerebral Blood Flow in Chronic Hydrocephalus A Parameter Indicating Shunt Failure — New Aspects

Prediction of outcome after shunt-therapy in chronic hydrocephalus syndrome is uncertain. Pathology reveals an impairment of cerebral blood flow (CBF). Based on this, we evaluated CBF and its significance for the assessment of prognosis. In 21 patients (mean age 69 years) selected for surgery, CBF was measured by PET (15O-H2O) before, about one week and 7 months (n = 14) after shunting. CBF was computed by a 1-compartmental model in the territories of the ACA, MCA and PCA. One PET slice in the height of the maximum projection of both cellae mediae was chosen. CBF data were standardized by cluster analysis. Three CBFClusters with significantly different CBF levels prior to shunting in the ACA, MCA and PCA territory, respectively, referred to the sample average (38.2 ml/100 ml/min) were found. These CBFClusters differed in clinical outcome: almost 50% and 90% of patients improved clinically in CBFCluster I, with a perfusion level lower than average, after one week and 7 months, respectively. In contrast, patients of CBFCluster II with an average perfusion did not improve. CBF changes 7 months after shunting related to global CBF before surgery showed a relationship with the clinical course. Clinical outcome corresponded with preoperative global CBF values. Cerebral blood flow lower than average forecasts clinical improvement. Our results suggest that measurement of CBF adds to the indication for surgery.

Guidelines for the Treatment of Head Injury in Adults

The workshop of scientific medical faculties (Arbeitsgemeinschaft wissenschaftlicher medizinischer Fakultäten [AWMF]) of Germany has asked societies of specific medical disciplines to jointly publish guidelines on the treatment of diseases and injuries. On behalf of the Deutsche Gesellschaft für Neurochirurgie, its commission on guidelines initiated an interdisciplinary approach to publish guidelines on the treatment of head injury in adults. These guidelines were published in German by the AWMF in late 2015. Because these guidelines have received widespread attention in Germany and became fundamental for research in head injuries, we have translated the German version into English to make it accessible to the international scientific community.