Abstract Up to 39% of children operated for a posterior fossa tumor develop the cerebellar mutism syndrome. Although they are alert and cooperative, with normal language comprehension, they are ...unable to speak. In addition, patients may demonstrate apathy, bladder and bowel incontinence and long-term language and cognitive disturbances. This devastating syndrome is at the same time intriguing, because it confirms a role for the cerebellum in language and cognitive functions. Recent investigations have led to new insights regarding the cerebellar mutism syndrome. The commonly accepted hypothesis states that the mutism is caused by a hypofunction of cerebral hemispheres, due to damage to the superior cerebellar peduncle and functional disruption of the cerebello-cerebral circuitry. This article focuses on the evidence for and against this hypothesis and its clinical consequences.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
Brain hypoxia can occur after non-traumatic subarachnoid hemorrhage (SAH), even when levels of intracranial pressure (ICP) remain normal. Brain tissue oxygenation (PbtO
2
) can be measured ...as a part of a neurological multimodal neuromonitoring. Low PbtO
2
has been associated with poor neurologic recovery. There is scarce data on the impact of PbtO
2
guided-therapy on patients’ outcome. This single-center cohort study (June 2014–March 2020) included all patients admitted to the ICU after SAH who required multimodal monitoring. Patients with imminent brain death were excluded. Our primary goal was to assess the impact of PbtO
2
-guided therapy on neurological outcome. Secondary outcome included the association of brain hypoxia with outcome. Of the 163 patients that underwent ICP monitoring, 62 were monitored with PbtO
2
and 54 (87%) had at least one episode of brain hypoxia. In patients that required treatment based on neuromonitoring strategies, PbtO
2
-guided therapy (OR 0.33 CI 95% 0.12–0.89) compared to ICP-guided therapy had a protective effect on neurological outcome at 6 months. In this cohort of SAH patients, PbtO
2
-guided therapy might be associated with improved long-term neurological outcome, only when compared to ICP-guided therapy.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Synthetic MR provides qualitative and quantitative multi-parametric data about tissue properties in a single acquisition. Its use in stroke imaging is not yet established. We compared ...synthetic and conventional image quality and studied synthetic relaxometry of acute and chronic ischemic lesions to investigate its interest for stroke imaging. We prospectively acquired synthetic and conventional brain MR of 43 consecutive adult patients with suspected stroke. We studied a total of 136 lesions, of which 46 DWI-positive with restricted ADC (DWI + /rADC), 90 white matter T2/FLAIR hyperintensities (WMH) showing no diffusion restriction, and 430 normal brain regions (NBR). We assessed image quality for lesion definition according to a 3-level score by two readers of different experiences. We compared relaxometry of lesions and regions of interest. Synthetic images were superior to their paired conventional images for lesion definition except for sFLAIR (sT1 or sPSIR vs. cT1 and sT2 vs. cT2 for DWI + /rADC and WMH definition;
p
values < .001) with substantial to almost perfect inter-rater reliability (κ ranging from 0.711 to 0.932,
p
values < .001). We found significant differences in relaxometry between lesions and NBR and between acute and chronic lesions (T1, T2, and PD of DWI + /rADC or WMH vs. mirror NBR;
p
values < .001; T1 and PD of DWI + /rADC vs. WMH;
p
values of 0.034 and 0.008). Synthetic MR may contribute to stroke imaging by fast generating accessible weighted images for visual inspection derived from rapidly acquired relaxometry data. Moreover, this synthetic relaxometry could differentiate acute and chronic ischemic lesions.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Brain tissue oxygenation (PbtO2)-guided therapy can improve the neurological outcome of traumatic brain injury (TBI) patients. With several Phase-III ongoing studies, most of the existing evidence is ...based on before-after cohort studies and a phase-II randomized trial. The aim of this study was to assess the effectiveness of PbtO2-guided therapy in a single-center cohort. We performed a retrospective analysis of consecutive severe TBI patients admitted to our center who received either intracranial pressure (ICP) guided therapy (from January 2012 to February 2016) or ICP/PbtO2-guided therapy (February 2017 to December 2019). A genetic matching was performed based on covariates including demographics, comorbidities, and severity scores on admission. Intracranial hypertension (IH) was defined as ICP > 20 mmHg for at least 5 min. Brain hypoxia (BH) was defined as PbtO2 < 20 mmHg for at least 10 min. IH and BH were targeted by specific interventions. Mann−Whitney U and Fisher’s exact tests were used to assess differences between groups. A total of 35 patients were matched in both groups: significant differences in the occurrence of IH (ICP 85.7% vs. ICP/PbtO2 45.7%, p < 0.01), ICU length of stay 6 (3−13) vs. 16 (9−25) days, p < 0.01 and Glasgow Coma Scale at ICU discharge 10 (5−14) vs. 13 (11−15), p = 0.036 were found. No significant differences in ICU mortality and Glasgow Outcome Scales at 3 months were observed. This study suggests that the role of ICP/PbtO2-guided therapy should await further confirmation in well-conducted large phase III studies.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•A new stratagem is proposed to improve thermal efficiency of Rankine cycles.•Three new configurations are optimized by means of numerical simulations.•The Rankine-1SCR design is advantageous for ...1338 different fluid combinations.•The Rankine-2SCR design is advantageous for 772 different fluid combinations.•The Rankine-3SCR design is advantageous for 768 different fluid combinations.
In this paper, three different modifications of the basic Rankine thermodynamic cycle are proposed. The objective is to increase the thermal efficiency of power systems based on Rankine cycles. The three new systems are named “Rankine-1SCR”, “Rankine-2SCR”, and “Rankine-3SCR” cycles, and they consist of linking a refrigeration cycle to the basic Rankine cycle. The idea is to use the refrigeration cycle to create a low temperature heat sink for the Rankine cycle. These three new power plant configurations are modeled and optimized with numerical tools, and then they are compared with the basic Rankine cycle. The objective function is the thermal efficiency of the systems (i.e., net power output (kW) divided by heat rate (kW) entering the system), and the design variables are the operating temperatures within the systems. Among the 84×84 (i.e., 7056) possible combinations of working and cooling fluids investigated in this paper, it is shown that: (i) the Rankine-1SCR system is advantageous for 1338 different fluid combinations, (ii) the Rankine-2SCR system is advantageous for 772 different fluid combinations, and (iii) the Rankine-3SCR system is advantageous for 768 different fluid combinations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
There is scant knowledge of dentists' total prescribing patterns, and little is published on this internationally. The Norwegian Prescription Database (NorPD) includes data on all dispensed ...prescription medication in Norway from 2004 and can be used to investigate how dentists' prescribing has changed over time. There are few Norwegian guidelines supporting dentists' prescribing, and Norwegian legislation on dentists' prescribing rights leaves room for interpretation. The aim of this study was therefore to give an overview of all prescribing from dentists in Norway in the period 2005 to 2015 and to identify trends in their prescribing pattern over this time span. We also give characteristics of the prescribing dentists.
The study had a retrospective pharmacoepidemiologic design. Data on all medication prescribed by dentists and dispensed from Norwegian pharmacies in the time period 2005 to 2015 were extracted from the NorPD. Changes over time in the prescribers, patients, and medications are reported.
There was an increase of 50% in total number of prescriptions from dentists in Norway from 2005 to 2015; adjusted for the growth in population, there was a 33% increase. The majority of prescriptions from dentists were for antibiotics and analgesics; however, the data reveal that the dentists prescribed from all major therapeutic groups. Dentists increased antibiotic prescribing in a period when total antibiotic prescribing in Norway decreased.
Our study finds antibiotics and analgesics dominate prescriptions from Norwegian dentists and shows an increase in use over time. It highlights the need for creating evidence-based prescribing guidelines for dentists and for ensuring that existing guidelines are implemented.
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BFBNIB, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Six interstage heating processes are applied to geothermal Double-Flash cycles.•Interstage heating reduces the turbines moisture content by 50%.•Interstage heating increases specific output by ...5%.•Interstage heating decreases required cooling capacity by 10%.•Mixture-Heating processes provided the best results.
In this paper, six different modifications of the Double-Flash power plants are proposed. These modifications are named “interstage heating” and consist of additional heat exchangers properly located in the system. The six interstage heating designs are analysed, optimized and then compared to an optimized Double-Flash reference power plant. The objective function is the power plant specific output (kJ/kg), and the design variables are the separator temperatures (°C) and the split fraction. Optimizations are performed for a wide range of reservoir temperatures (i.e., from 140°C to 240°C). Results show that interstage heating processes may increase the specific output of the plant by about 5%, decrease the liquid content in the low pressure turbine by about 50%, and decrease the required cooling capacity of the plant by about 10%. On the other hand, the analysis showed that the new designs proposed have negligible influence on the high pressure turbine liquid content or on the silica saturation coefficient.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Intracranial multimodal monitoring (iMMM) is increasingly used for neurocritical care. However, concerns arise regarding iMMM invasiveness considering limited evidence in its clinical significance ...and safety profile. We conducted a synthesis of evidence regarding complications associated with iMMM to delineate its safety profile. We performed a systematic review and meta-analysis (PROSPERO Registration Number: CRD42021225951) according to the Preferred Reporting Items for Systematic Review and Meta-Analysis and Peer Review of Electronic Search Strategies guidelines to retrieve evidence from studies reporting iMMM use in humans that mention related complications. We assessed risk of bias using the Newcastle–Ottawa Scale and funnel plots. The primary outcomes were iMMM complications. The secondary outcomes were putative risk factors. Of the 366 screened articles, 60 met the initial criteria and were further assessed by full-text reading. We included 22 studies involving 1206 patients and 1434 iMMM placements. Most investigators used a bolt system (85.9%) and a three-lumen device (68.8%), mainly inserting iMMM into the most injured hemisphere (77.9%). A total of 54 postoperative intracranial hemorrhages (pooled rate of 4%; 95% confidence interval CI 0–10%;
I
2
86%,
p
< 0.01 random-effects model) was reported, along with 46 misplacements (pooled rate of 6%; 95% CI 1–12%;
I
2
78%,
p
< 0.01) and 16 central nervous system infections (pooled rate of 0.43%; 95% CI 0–2%;
I
2
64%,
p
< 0.01). We found 6 system breakings, 18 intracranial bone fragments, and 5 cases of pneumocephalus. Currently, iMMM systems present a similar safety profile as intracranial devices commonly used in neurocritical care. Long-term outcomes of prospective studies will complete the benefit-risk assessment of iMMM in neurocritical care. Consensus-based reporting guidelines on iMMM use are needed to bolster future collaborative efforts.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Background
Intracranial multimodality monitoring (iMMM) is increasingly used in acute brain-injured patients; however, safety and reliability remain major concerns to its routine implementation.
...Methods
We performed a retrospective study including all patients undergoing iMMM at a single European center between July 2016 and January 2020. Brain tissue oxygenation probe (PbtO
2
), alone or in combination with a microdialysis catheter and/or an 8-contact depth EEG electrode, was inserted using a triple-lumen bolt system and targeting normal-appearing at-risk brain area on the injured side, whenever possible. Surgical complications, adverse events, and technical malfunctions, directly associated with iMMM, were collected. A blinded imaging review was performed by an independent radiologist.
Results
One hundred thirteen patients with 123 iMMM insertions were included for a median monitoring time of 9 3–14 days. Of those, 93 (76%) patients had only PbtO
2
probe insertion and 30 (24%) had also microdialysis and/or iEEG monitoring. SAH was the most frequent indication for iMMM (
n
= 60, 53%). At least one complication was observed in 67/123 (54%) iMMM placement, corresponding to 58/113 (51%) patients. Misplacement was observed in 16/123 (13%), resulting in a total of 6/16 (38%) malfunctioning PbtO
2
catheters. Intracranial hemorrhage was observed in 14 iMMM placements (11%), of which one required surgical drainage. Five placements were complicated by pneumocephalus and 4 with bone fragments; none of these requires additional surgery. No CNS infection related to iMMM was observed. Seven (6%) probes were accidentally dislodged and 2 probes (2%) were accidentally broken. Ten PbtO
2
probes (8%) presented a technical malfunction after a median of 9 ranges: 2–24 days after initiation of monitoring and 4 of them were replaced.
Conclusions
In this study, a high occurrence of complications related to iMMM was observed, although most of them did not require specific interventions and did not result in malfunctioning monitoring.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
New, efficient, realizable and hyperbolic interpolative-based first- and second-order maximum entropy, M1 and M2, respectively, moment closures for providing approximate numerical solutions to the ...radiative transfer equation (RTE) in both gray (for M2) and non-gray (for M1 and M2) participating media are proposed and described. These newly-developed interpolative closures allow to accurately reproduce maximum entropy solutions at a fraction of the computational costs associated with the expensive direct numerical solution of the entropy optimization problem. New boundary conditions, based on the method of characteristics, are also proposed for use with the hyperbolic systems of moment equations arising from the M1 and M2 closures. The predictive capabilities of the M1 and M2 closures are then assessed by comparing their solutions to those of the more commonly adopted first-order, P1, and third-order, P3, spherical harmonic moment closures, as well as the popular discrete ordinates method (DOM). The assessments involve both gray and non-gray radiative heat transfer within one- and two-dimensional enclosures, with prescribed thermochemical quantities, as well as reactive flows simulations of high-pressure sooting laminar co-flow diffusion flames.The numerical results for most of the test cases involving non-reactive flows show that the M1 closure provides solutions of at least comparable accuracy to those of the P3 closure while incurring only a rather modest or minor increase in computational costs relative to the P1 closure. In situations involving crossing streams of photons emanating from different directions, the M2 closure represents a better alternative to the M1 closure which cannot properly capture such phenomena and may yield unphysical solutions, though the computational costs of the former are observed to be more involved than those associated with the latter. For the high-pressure reactive flow simulations, the predictive capabilities of the M1 and M2 closures were observed to be superior to those of the P1 closure for all the pressures studied. On the other hand, the P3 closure was observed to be of comparable accuracy to the M2 closure at low pressures. However, at higher pressures, both the M1 and M2 closures displayed a trend of increasingly improved accuracy compared to the P3 closure.
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