The variability in nociceptive flexion reflex threshold measurement is mostly caused by probabilistic effects of the estimation algorithms: a simulation study.

OBJECTIVES: The nociceptive flexion reflex (NFR) and its threshold are frequently used to investigate spinal nociception in humans. Since this threshold (NFRT) is a probabilistic measure, specific algorithms are used for NFRT estimation based on the stochastic occurrence of reflexes at different stimulus intensities. We used a validated simulation model of the NFR to investigate the amount of NFRT measurement variability induced by different estimation algorithms in a steady setting of reduced external influences. METHODS: We simulated the behavior of different estimation algorithms in subjects with an artificially steady baseline NFRT variability (standard deviation: 0 mA) or low baseline NFRT variability (standard deviation: 0.156 mA), equaling a quiet experimental setting. The obtained data were analyzed for NFRT measurement variability caused by the algorithms compared to the baseline variability reflecting other physiological influences. RESULTS: The standard deviation of the NFRT estimated by the different algorithms ranged between 0.381 and 3.464 mA with 96.8% to 99.6% of the measurement variability attributed to the algorithm used. Out of the investigated algorithms the dynamic staircase algorithm was most precise. CONCLUSION: The NFRT measurement variability observed during quiet and steady experimental sessions is mostly caused by the properties of the estimation algorithms, due to the probabilistic nature of the reflex occurrence. Our results give reference for choosing the optimal estimation algorithm to improve measurement precision.

Representation of evidence-based clinical practice guideline recommendations on FHIR.

BACKGROUND: Various formalisms have been developed to represent clinical practice guideline recommendations in a computer-interpretable way. However, none of the existing formalisms leverage the structured and computable information that emerge from the evidence-based guideline development process. Thus, we here propose a FHIR-based format that uses computer-interpretable representations of the knowledge artifacts that emerge during the process of evidence-based guideline development to directly serve as the basis of evidence-based recommendations. METHODS: We identified the information required to represent evidence-based clinical practice guideline recommendations and reviewed the knowledge artifacts emerging during the evidence-based guideline development process. We then conducted a consensus-based design process with domain experts to develop an information model for guideline recommendation representation that is structurally aligned to the evidence-based guideline recommendation development process and a corresponding representation based on FHIR resources developed for evidence-based medicine (EBMonFHIR). The resulting recommendations were modelled and represented in conformance with the FHIR Clinical Guidelines (CPG-on-FHIR) implementation guide. RESULTS: The information model of evidence-based clinical guideline recommendations and its EBMonFHIR-/CPG-on-FHIR-based representation contain the clinical contents of individual guideline recommendations, a set of metadata for the recommendations, the ratings for the recommendations (e.g., strength of recommendation, certainty of overall evidence), the ratings of certainty of evidence for individual outcomes (e.g., risk of bias) and links to the underlying evidence (systematic reviews based on primary studies). We created profiles and an implementation guide for all FHIR resources required to represent the knowledge artifacts generated during evidence-based guideline development and their re-use as the basis for recommendations and used the profiles to implement an exemplary clinical guideline recommendation. CONCLUSIONS: The FHIR implementation guide presented here can be used to directly link the evidence assessment process of evidence-based guideline recommendation development, i.e. systematic reviews and evidence grading, and the underlying evidence from primary studies to the resulting guideline recommendations. This not only allows the evidence on which recommendations are based on to be evaluated transparently and critically, but also enables guideline developers to leverage computable evidence in a more direct way to facilitate the generation of computer-interpretable guideline recommendations.

Electroencephalogram-based prediction and detection of responsiveness to noxious stimulation in critical care patients: a retrospective single-centre analysis.

BACKGROUND: Monitoring of pain and nociception in critical care patients unable to self-report pain remains a challenge, as clinical signs are neither sensitive nor specific. Available technical approaches are limited by various constraints. We investigated the electroencephalogram (EEG) for correlates that precede or coincide with behavioural nociceptive responses to noxious stimulation. METHODS: In this retrospective study, we analysed frontal EEG recordings of 64 critical care patients who were tracheally intubated and ventilated before, during, and after tracheal suctioning. We investigated EEG power bands for correlates preceding or coinciding with behavioural responses (Behavioural Pain Scale ≥7). We applied the Mann-Whitney U-test to calculate corresponding P-values. RESULTS: Strong behavioural responses were preceded by higher normalised power in the 2.5-5 Hz band (+17.1%; P<0.001) and lower normalised power in the 0.1-1.5 Hz band (-10.5%; P=0.029). After the intervention, strong behavioural responses were associated with higher normalised EEG power in the 2.5-5 Hz band (+16.6%; P=0.021) and lower normalised power in the 8-12 Hz band (-51.2%; P=0.037) CONCLUSIONS: We observed correlates in EEG band power that precede and coincide with behavioural responses to noxious stimulation. Based on previous findings, some of the power bands could be linked to processing of nociception, arousal, or sedation effects. The power bands more closely related to nociception and arousal could be used to improve monitoring of nociception and to optimise analgesic management in critical care patients. CLINICAL TRIAL REGISTRATION: DRKS00011206.

Automated Monitoring of Adherence to Evidenced-Based Clinical Guideline Recommendations: Design and Implementation Study.

BACKGROUND: Clinical practice guidelines are systematically developed statements intended to optimize patient care. However, a gapless implementation of guideline recommendations requires health care personnel not only to be aware of the recommendations and to support their content but also to recognize every situation in which they are applicable. To not miss situations in which recommendations should be applied, computerized clinical decision support can be provided through a system that allows an automated monitoring of adherence to clinical guideline recommendations in individual patients. OBJECTIVE: This study aims to collect and analyze the requirements for a system that allows the monitoring of adherence to evidence-based clinical guideline recommendations in individual patients and, based on these requirements, to design and implement a software prototype that integrates guideline recommendations with individual patient data, and to demonstrate the prototype's utility in treatment recommendations. METHODS: We performed a work process analysis with experienced intensive care clinicians to develop a conceptual model of how to support guideline adherence monitoring in clinical routine and identified which steps in the model could be supported electronically. We then identified the core requirements of a software system to support recommendation adherence monitoring in a consensus-based requirements analysis within the loosely structured focus group work of key stakeholders (clinicians, guideline developers, health data engineers, and software developers). On the basis of these requirements, we designed and implemented a modular system architecture. To demonstrate its utility, we applied the prototype to monitor adherence to a COVID-19 treatment recommendation using clinical data from a large European university hospital. RESULTS: We designed a system that integrates guideline recommendations with real-time clinical data to evaluate individual guideline recommendation adherence and developed a functional prototype. The needs analysis with clinical staff resulted in a flowchart describing the work process of how adherence to recommendations should be monitored. Four core requirements were identified: the ability to decide whether a recommendation is applicable and implemented for a specific patient, the ability to integrate clinical data from different data formats and data structures, the ability to display raw patient data, and the use of a Fast Healthcare Interoperability Resources-based format for the representation of clinical practice guidelines to provide an interoperable, standards-based guideline recommendation exchange format. CONCLUSIONS: Our system has advantages in terms of individual patient treatment and quality management in hospitals. However, further studies are needed to measure its impact on patient outcomes and evaluate its resource effectiveness in different clinical settings. We specified a modular software architecture that allows experts from different fields to work independently and focus on their area of expertise. We have released the source code of our system under an open-source license and invite for collaborative further development of the system.

Cognitive Impairment Is Associated with Absolute Intraoperative Frontal α-Band Power but Not with Baseline α-Band Power: A Pilot Study.

BACKGROUND: Cognitive abilities decline with aging, leading to a higher risk for the development of postoperative delirium or postoperative neurocognitive disorders after general anesthesia. Since frontal α-band power is known to be highly correlated with cognitive function in general, we hypothesized that preoperative cognitive impairment is associated with lower baseline and intraoperative frontal α-band power in older adults. METHODS: Patients aged ≥65 years undergoing elective surgery were included in this prospective observational study. Cognitive function was assessed on the day before surgery using six age-sensitive cognitive tests. Scores on those tests were entered into a principal component analysis to calculate a composite "g score" of global cognitive ability. Patient groups were dichotomized into a lower cognitive group (LC) reaching the lower 1/3 of "g scores" and a normal cognitive group (NC) consisting of the upper 2/3 of "g scores." Continuous pre- and intraoperative frontal electroencephalograms (EEGs) were recorded. EEG spectra were analyzed at baseline, before start of anesthesia medication, and during a stable intraoperative period. Significant differences in band power between the NC and LC groups were computed by using a frequency domain (δ 0.5-3 Hz, θ 4-7 Hz, α 8-12 Hz, ß 13-30 Hz)-based bootstrapping algorithm. RESULTS: Of 38 included patients (mean age 72 years), 24 patients were in the NC group, and 14 patients had lower cognitive abilities (LC). Intraoperative α-band power was significantly reduced in the LC group compared to the NC group (NC -1.6 [-4.48/1.17] dB vs. LC -6.0 [-9.02/-2.64] dB), and intraoperative α-band power was positively correlated with "g score" (Spearman correlation: r = 0.381; p = 0.018). Baseline EEG power did not show any associations with "g." CONCLUSIONS: Preoperative cognitive impairment in older adults is associated with intraoperative absolute frontal α-band power, but not baseline α-band power.

Investigation of the Usability of Computerized Critical Care Information Systems in Germany.

INTRODUCTION: The term "usability" describes how effectively, efficiently, and with what level of user satisfaction an information system can be used to accomplish specific goals. Computerized critical care information systems (CCISs) with high usability increase quality of care and staff satisfaction, while reducing medication errors. Conversely, systems lacking usability can interrupt clinical workflow, facilitate errors, and increase charting time. The aim of this study was to investigate and compare usability across CCIS currently used in Germany. METHODS: In this study, German intensive care unit (ICU) nurses and physicians completed a specialized, previously validated, web-based questionnaire. The questionnaire assessed CCIS usability based on three rating models: an overall rating of the systems, a model rating technical usability, and a model rating task-specific usability. RESULTS: We analyzed results from 535 survey participants and compared eight different CCIS commonly used in Germany. Our results showed that usability strongly differs across the compared systems. The system ICUData had the best overall rating and technical usability, followed by the platforms ICM and MetaVision. The same three systems performed best in the rating of task-specific usability without significant differences between each other. Across all systems, overall ratings were more dependent on ease-of-use aspects than on aspects of utility/functionality, and the general scope of the functions offered was rated better than how well the functions are realized. DISCUSSION: Our results suggest that manufacturers should shift some of their effort away from the development of new features and focus more on improving the ease-of-use and quality of existing features.

Effects of propofol anesthesia on the processing of noxious stimuli in the spinal cord and the brain.

Drug-induced unconsciousness is an essential component of general anesthesia, commonly attributed to attenuation of higher-order processing of external stimuli and a resulting loss of information integration capabilities of the brain. In this study, we investigated how the hypnotic drug propofol at doses comparable to those in clinical practice influences the processing of somatosensory stimuli in the spinal cord and in primary and higher-order cortices. Using nociceptive reflexes, somatosensory evoked potentials and functional magnet resonance imaging (fMRI), we found that propofol abolishes the processing of innocuous and moderate noxious stimuli at low to medium concentration levels, but that intense noxious stimuli evoked spinal and cerebral responses even during deep propofol anesthesia that caused profound electroencephalogram (EEG) burst suppression. While nociceptive reflexes and somatosensory potentials were affected only in a minor way by further increasing doses of propofol after the loss of consciousness, fMRI showed that increasing propofol concentration abolished processing of intense noxious stimuli in the insula and secondary somatosensory cortex and vastly increased processing in the frontal cortex. As the fMRI functional connectivity showed congruent changes with increasing doses of propofol - namely the temporal brain areas decreasing their connectivity with the bilateral pre-/postcentral gyri and the supplementary motor area, while connectivity of the latter with frontal areas is increased - we conclude that the changes in processing of noxious stimuli during propofol anesthesia might be related to changes in functional connectivity.

Utility of nociceptive flexion reflex threshold and bispectral index to predict movement responses under propofol anaesthesia.

INTRODUCTION: The nociceptive flexion reflex threshold (NFRT) is a promising tool to monitor analgesia during general anaesthesia. Clinical studies have shown that the NFRT allows to predict movement responses to painful stimuli under a combined anaesthetic regime of sedative and opioid agents. Experimental studies indicated that the NFRT is also able to predict such movement responses under an exclusively sedative regime like propofol mono-anaesthesia. Therefore, we performed this study to investigate the ability of the NFRT to predict movement responses to painful stimuli in patients during a clinical propofol mono-anaesthesia. METHODS: We investigated 140 cardiac surgery patients during their postoperative phase under propofol mono-anaesthesia. NFRT and bispectral index (BIS) were determined in each patient right before endotracheal suctioning or painful electrical test stimulation. Prediction probabilities were calculated to quantify how accurate each measure is able to predict movement responses to the stimuli. RESULTS: The 124 patients included in the analysis received a median propofol dosage of 3.2 (2.5-3.9) [median (IQR)] mg/kg/h. The included patients showed 287 movement responses after a total of 725 investigated stimuli. The prediction probabilities for positive movement responses were 0.63 (95%CI: 0.59-0.67) for the NFRT and 0.69 (95%CI: 0.65-0.73) for the BIS. CONCLUSIONS: The NFRT allows the prediction of movement responses under propofol mono-anaesthesia, which confirms its utility as a monitor to predict movement responses under general anaesthesia. The BIS allows an even more accurate prediction, although it does not reflect the physiological structures of movement suppression, but correlates closely with the dose of propofol. TRIAL REGISTRATION: German clinical trial register (DRKS00003062, Deutsches Register Klinischer Studien).

Intraoperative monitoring of analgesia using nociceptive reflexes correlates with delayed extubation and immediate postoperative pain: A prospective observational study.

BACKGROUND: Immediate postoperative pain could be prevented by the administration of long-lasting analgesics before the end of the anaesthesia. However, to prevent over or underdosing of analgesics under anaesthesia, tools are required to estimate the analgesia-nociception balance. OBJECTIVE: We investigated whether the pupillary dilation reflex (PDR) and the nociceptive flexion reflex (NFR) at the end of general anaesthesia correlate with immediate postoperative pain, as a sign of analgesic underdosing, and with delayed tracheal extubation as a sign of analgesic overdosing. DESIGN: Prospective observational study. SETTING: Klinikum im Friedrichshain, Berlin, Germany, from May 2013 to April 2015. PATIENTS: A total of 110 patients scheduled for primary hip arthroplasty under general anaesthesia. OBSERVATIONS: Psychometric and clinical data were obtained preoperatively. The PDR and the NFR were assessed preoperatively and at the end of anaesthesia. Shortly after extubation of the trachea, patients rated their pain intensity. ENDPOINTS: The primary endpoint was the immediate postoperative numeric rating scale pain intensity (0 to 10) and the secondary endpoint was the length of the time interval between reflex measurements and tracheal extubation. RESULTS: PDR correlated significantly with the immediate postoperative pain intensity (Spearman's ρ = -0.28, P < 0.01). PDR and NFR correlated significantly with the time interval until extubation (ρ = 0.33/0.26, both P < 0.01). Multivariable linear regression models were able to predict 38% of the variability of immediate postoperative pain intensity and 44% of the variability of the time interval until extubation. The intraoperative nociceptive reflex thresholds were the strongest factors in both multivariable models, only exceeded by the preoperative reflex measurements in the model for postoperative pain. CONCLUSION: The investigated nociceptive reflexes reflected the analgesia-nociception balance under general anaesthesia. The preoperative reflexes provide additional information about individual subjective pain sensitivity. TRIAL REGISTRATION: Deutsches Register Klinischer Studien, DRKS (registration number DRKS00000665).

Design and validation of a questionnaire to evaluate the usability of computerized critical care information systems.

The implementation of computerized critical care information systems (CCIS) can improve the quality of clinical care and staff satisfaction, but also holds risks of disrupting the workflow with consecutive negative impacts. The usability of CCIS is one of the key factors determining their benefits and weaknesses. However, no tailored instrument exists to measure the usability of such systems. Therefore, the aim of this study was to design and validate a questionnaire that measures the usability of CCIS. Following a mixed-method design approach, we developed a questionnaire comprising two evaluation models to assess the usability of CCIS: (1) the task-specific model rates the usability individually for several tasks which CCIS could support and which we derived by analyzing work processes in the ICU; (2) the characteristic-specific model rates the different aspects of the usability, as defined by the international standard "ergonomics of human-system interaction". We tested validity and reliability of the digital version of the questionnaire in a sample population. In the sample population of 535 participants both usability evaluation models showed a strong correlation with the overall rating of the system (multiple correlation coefficients ≥0.80) as well as a very high internal consistency (Cronbach's alpha ≥0.93). The novel questionnaire is a valid and reliable instrument to measure the usability of CCIS and can be used to study the influence of the usability on their implementation benefits and weaknesses.

Informing pandemic management in Germany with trustworthy, living evidence syntheses and guideline development: Lessons learned from the COVID-19 evidence ecosystem (CEOsys).

OBJECTIVE: We present the 'COVID-19 evidence ecosystem' (CEOsys) as a German network to inform pandemic management and to support clinical and public health decision-making. We discuss challenges faced when organizing the ecosystem and derive lessons learned for similar networks acting during pandemics or health-related crises. STUDY DESIGN AND SETTING: Bringing together 18 university hospitals and additional institutions, CEOsys key activities included research prioritization, conducting living systematic reviews, supporting evidence-based (living) guidelines, knowledge translation, detecting research gaps and deriving recommendations, backed by technical infrastructure and capacity building. RESULTS: CEOsys rapidly produced 31 high-quality evidence syntheses and supported three living guidelines on COVID-19-related topics, while also developing methodological procedures. Challenges included CEOsys' late initiation in relation to the pandemic outbreak, the delayed prioritization of research questions, the continuously evolving COVID-19-related evidence, and establishing a technical infrastructure. Methodological-clinical tandems, the cooperation with national guideline groups and international collaborations were key for efficiency. CONCLUSION: CEOsys provided a proof-of-concept for a functioning evidence ecosystem at the national level. Lessons learned include that similar networks should, among others, involve methodological and clinical key stakeholders early on, aim for (inter-)national collaborations, and systematically evaluate their value. We particularly call for a sustainable network.

SPARC prevents maturation of cholinergic presynaptic terminals.

Secreted Protein Acidic and Rich in Cysteine (SPARC) is a matricellular protein produced by glial cells. Although it is highly expressed in synaptogenic areas in the developing nervous system, it is still unclear whether this molecule displays an action on synaptic activity. We show that nanomolar concentrations of SPARC favour a more efficient synapse formation and increase short term depression in single cell cholinergic microcultures. The change in synaptic plasticity, which is also observed when SPARC is locally secreted on stable synapses for 24-48 h, is caused by a high release probability and a reduction in the size of the rapidly releasable pool of vesicles. Both features are attributable to synapses operating at an immature stage as demonstrated by correlative electrophysiology and electron microscopy experiments. Presynaptic terminals developed in the presence of SPARC display few cytoplasmic vesicles and two to threefold decrease in the number of docked vesicles at active zones. At the postsynaptic level, the analysis of miniature excitatory postsynaptic currents suggests SPARC has little effect on the number of nicotinic receptors but might alter their composition. The widespread distribution of SPARC makes current findings potentially relevant to other excitatory synapses and development of neuronal circuits.

Systematic Review and Meta-analysis: Outcomes After Descemet Membrane Endothelial Keratoplasty Versus Ultrathin Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: To compare the efficacy and safety of ultrathin Descemet stripping (automated) endothelial keratoplasty (UT-DS(A)EK) versus Descemet membrane endothelial keratoplasty (DMEK) for the treatment of Fuchs endothelial dystrophy (FED) and bullous keratopathy (BK). DESIGN: Systematic review and meta-analysis. METHODS: Literature containing DMEK and UT-DSAEK were searched in the Cochrane Database of Systematic Reviews, PubMed, EMBASE, LILACS, and through manual reference searching. Studies were included that measured the outcome of interventions-including best corrected visual acuity (BCVA), endothelial cell density (ECD), and postoperative complications, especially graft detachment with the need of re-bubbling, graft rejection, graft failure, and postoperative elevated intraocular pressure (IOP)-in patients with FED and BK. Included outcomes were pooled as standardized mean differences (SMD) or risk ratios (RR) using random effects models. Inter-study heterogeneity was assessed using the Q-test and I2 statistic. RESULTS: Seven (of 163) studies met all the inclusion and exclusion criteria. Meta-analysis showed a significantly better BCVA 12 months postoperatively, but an increased re-bubbling rate in eyes after DMEK compared with eyes after UT-DS(A)EK (BCVA: SMD = 0.50 [95% CI 0.27-0.74] and re-bubbling rate: RR = 0.33 [95% CI 0.16-0.67]). All other parameters did not differ significantly between both interventions, although estimates were imprecise (graft failure: RR = 0.65 [95% CI 0.18-2.30], graft rejection: RR = 1.40 [95% CI 0.27-7.30], and postoperative intraocular pressure elevation: RR = 1.14 [95% CI 0.60-2.18]). Postoperative SMDs of ECD could not be evaluated due to significant heterogeneity between studies. CONCLUSIONS: Although the improvement in BCVA was higher after UT-DS(A)EK than after conventional DS(A)EK, the BCVA after DMEK was still superior. The complication rates were comparable for both procedures, except for the higher rate of re-bubbling after DMEK.

Interoperable, Domain-Specific Extensions for the German Corona Consensus (GECCO) COVID-19 Research Data Set Using an Interdisciplinary, Consensus-Based Workflow: Data Set Development Study.

Background: The COVID-19 pandemic has spurred large-scale, interinstitutional research efforts. To enable these efforts, researchers must agree on data set definitions that not only cover all elements relevant to the respective medical specialty but also are syntactically and semantically interoperable. Therefore, the German Corona Consensus (GECCO) data set was developed as a harmonized, interoperable collection of the most relevant data elements for COVID-19-related patient research. As the GECCO data set is a compact core data set comprising data across all medical fields, the focused research within particular medical domains demands the definition of extension modules that include data elements that are the most relevant to the research performed in those individual medical specialties. Objective: We aimed to (1) specify a workflow for the development of interoperable data set definitions that involves close collaboration between medical experts and information scientists and (2) apply the workflow to develop data set definitions that include data elements that are the most relevant to COVID-19-related patient research regarding immunization, pediatrics, and cardiology. Methods: We developed a workflow to create data set definitions that were (1) content-wise as relevant as possible to a specific field of study and (2) universally usable across computer systems, institutions, and countries (ie, interoperable). We then gathered medical experts from 3 specialties-infectious diseases (with a focus on immunization), pediatrics, and cardiology-to select data elements that were the most relevant to COVID-19-related patient research in the respective specialty. We mapped the data elements to international standardized vocabularies and created data exchange specifications, using Health Level Seven International (HL7) Fast Healthcare Interoperability Resources (FHIR). All steps were performed in close interdisciplinary collaboration with medical domain experts and medical information specialists. Profiles and vocabulary mappings were syntactically and semantically validated in a 2-stage process. Results: We created GECCO extension modules for the immunization, pediatrics, and cardiology domains according to pandemic-related requests. The data elements included in each module were selected, according to the developed consensus-based workflow, by medical experts from these specialties to ensure that the contents aligned with their research needs. We defined data set specifications for 48 immunization, 150 pediatrics, and 52 cardiology data elements that complement the GECCO core data set. We created and published implementation guides, example implementations, and data set annotations for each extension module. Conclusions: The GECCO extension modules, which contain data elements that are the most relevant to COVID-19-related patient research on infectious diseases (with a focus on immunization), pediatrics, and cardiology, were defined in an interdisciplinary, iterative, consensus-based workflow that may serve as a blueprint for developing further data set definitions. The GECCO extension modules provide standardized and harmonized definitions of specialty-related data sets that can help enable interinstitutional and cross-country COVID-19 research in these specialties.

Investigation of Behavioural Pain Scale, Critical Care Pain Observation Tool, nociceptive flexion reflex and pupillary dilatation reflex as predictors of behavioural reactions to nociceptive procedures in critically ill patients unable to self-report pain.

BACKGROUND: Procedural pain is a common burden in critical care treatment and the prediction of nociceptive reactions remains challenging. Thus, we investigated the Behavioural Pain Scale (BPS), the Critical Pain Observational Tool (CPOT), the nociceptive flexion reflex (NFR), the pupillary dilation reflex (PDR) and the Richmond Agitation-Sedation Scale (RASS) as predictors of behavioural reactions to nociceptive procedures. METHODS: In this monocentric, prospective, observational study, we analysed data of 128 critically ill adults unable to self-report pain to investigate the predictability of behavioural reactions to two procedures: endotracheal suctioning and turning. Next to routine clinical data, CPOT, BPS, PDR, NFR, RASS, propofol and sufentanil doses were recorded before the procedures. RESULTS: For endotracheal suctioning, NFR, BPS, CPOT and RASS showed predictive performances significantly better than chance, but none of them performed significantly better than the sufentanil dose rate. For turning, BPS, CPOT and RASS showed predictive performances significantly better than chance, but only the RASS performed significantly better than the propofol dose rate. CONCLUSIONS: Behavioural reactions to both investigated clinical procedures can be predicted by observational scales or nociceptive reflexes. For endotracheal suctioning, none of the predictors performed superior to using the sufentanil dose rate as a predictor. As using sufentanil as a predictor requires no extra effort in contrast to the other predictors, none of the here investigated tools seem advisable for predicting behavioural reactions to endotracheal suctioning. For patient turning, the RASS predicts reactions better than any other tool. SIGNIFICANCE: In this observational study, we demonstrate that behavioural reactions to potentially nociceptive procedures in critical care treatment can be predicted by observational scales and nociceptive reflexes. However, for endotracheal suctioning, none of the predictors is superior to using the opioid dose rate as a predictor. For patient turning, the RASS predicts reactions better than any other parameters.

Postsynaptic plasticity of cholinergic synapses underlies the induction and expression of appetitive and familiarity memories in Drosophila.

In vertebrates, several forms of memory-relevant synaptic plasticity involve postsynaptic rearrangements of glutamate receptors. In contrast, previous work indicates that Drosophila and other invertebrates store memories using presynaptic plasticity of cholinergic synapses. Here, we provide evidence for postsynaptic plasticity at cholinergic output synapses from the Drosophila mushroom bodies (MBs). We find that the nicotinic acetylcholine receptor (nAChR) subunit α5 is required within specific MB output neurons for appetitive memory induction but is dispensable for aversive memories. In addition, nAChR α2 subunits mediate memory expression and likely function downstream of α5 and the postsynaptic scaffold protein discs large (Dlg). We show that postsynaptic plasticity traces can be induced independently of the presynapse, and that in vivo dynamics of α2 nAChR subunits are changed both in the context of associative and non-associative (familiarity) memory formation, underlying different plasticity rules. Therefore, regardless of neurotransmitter identity, key principles of postsynaptic plasticity support memory storage across phyla.

Perioperative predictability of unsatisfactory functional outcomes 6 months after hip arthroplasty.

BACKGROUND: Aiming at an early identification of patients with an unsatisfactory outcome after hip arthroplasty we investigated the pre-, intra- and early postoperative predictability. METHODS: Using logistic regression models at nine different time points we calculated the area under the curve of the receiver operating characteristic (ROC-AUC) to compare the predictability of an unsatisfactory outcome. RESULTS: The predictability of unsatisfactory outcomes increased significantly from a ROC-AUC (95% CI) of 0.73 (0.62-0.84) in the preoperative setting to 0.85 (0.77-0.94) on day 2 after surgery. CONCLUSION: Most of the patients with unsatisfactory outcomes can be identified during the first days after surgery.

Resting state brain network functional connectivity is not associated with inflammatory markers and blood cell counts in older adults.

OBJECTIVE: Systemic inflammation and monocyte counts have previously been associated with changes in resting state functional connectivity (rsFC) in cross-sectional neuroimaging studies. We therefore investigated this association in a longitudinal study of older patients. METHODS: We performed a secondary analysis of longitudinal data from older patients who underwent functional magnet resonance imaging (fMRI) scans before and 3 months after elective surgery. Additionally, serum levels of C-reactive protein and Interleukin-6 as markers of inflammation and leukocyte, lymphocyte and monocyte counts were determined. Correlations between these markers and pre- or postoperative rsFC between regions previously associated with inflammatory markers were investigated using general linear regression models. RESULTS: We found no significant correlations between inflammatory markers or blood cell counts and mean connectivity within four resting state networks (RSNs), neither preoperatively nor postoperatively. Significant inter-region rsFC was found within these RSNs between a few regions either pre- or postoperatively, but no inter-region connections were consistently observed in both pre- and postoperative fMRI scans. CONCLUSIONS: Inflammatory markers and monocyte counts were not associated with rsFC in our study, contrasting previous results. SIGNIFICANCE: Multiple measurements in the same individuals, as performed here, provide a way to reduce the high risk of false positive results in fMRI studies. TRIAL REGISTRATION: Clinicaltrials.gov (registration number NCT02265263).

Predicting lethal courses in critically ill COVID-19 patients using a machine learning model trained on patients with non-COVID-19 viral pneumonia.

In a pandemic with a novel disease, disease-specific prognosis models are available only with a delay. To bridge the critical early phase, models built for similar diseases might be applied. To test the accuracy of such a knowledge transfer, we investigated how precise lethal courses in critically ill COVID-19 patients can be predicted by a model trained on critically ill non-COVID-19 viral pneumonia patients. We trained gradient boosted decision tree models on 718 (245 deceased) non-COVID-19 viral pneumonia patients to predict individual ICU mortality and applied it to 1054 (369 deceased) COVID-19 patients. Our model showed a significantly better predictive performance (AUROC 0.86 [95% CI 0.86-0.87]) than the clinical scores APACHE2 (0.63 [95% CI 0.61-0.65]), SAPS2 (0.72 [95% CI 0.71-0.74]) and SOFA (0.76 [95% CI 0.75-0.77]), the COVID-19-specific mortality prediction models of Zhou (0.76 [95% CI 0.73-0.78]) and Wang (laboratory: 0.62 [95% CI 0.59-0.65]; clinical: 0.56 [95% CI 0.55-0.58]) and the 4C COVID-19 Mortality score (0.71 [95% CI 0.70-0.72]). We conclude that lethal courses in critically ill COVID-19 patients can be predicted by a machine learning model trained on non-COVID-19 patients. Our results suggest that in a pandemic with a novel disease, prognosis models built for similar diseases can be applied, even when the diseases differ in time courses and in rates of critical and lethal courses.

Influence of midazolam premedication on intraoperative EEG signatures in elderly patients.

OBJECTIVE: To investigate the influence of midazolam premedication on the EEG-spectrum before and during general anesthesia in elderly patients. METHODS: Patients aged ≥65 years, undergoing elective surgery were included in this prospective observational study. A continuous pre- and intraoperative frontal EEG was recorded in patients who received premedication with midazolam (Mid, n = 15) and patients who did not (noMid, n = 30). Absolute power within the delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and beta (12-25 Hz) frequency-bands was analyzed in EEG-sections before (pre-induction), and after induction of anesthesia with propofol (post-induction), as well as during general anesthesia with either propofol or volatile-anesthetics (intra-operative). RESULTS: Pre-induction, α-power of Mid patients was lower compared with noMid-patients (α-power: Mid: -10.75 dB vs. noMid: -9.20 dB; p = 0.036). After induction of anesthesia Mid-patients displayed a stronger increase of frontal α-power resulting in higher absolute α-power at post-induction state, (α-power: Mid -3.56 dB vs. noMid: -6.69 dB; p = 0.004), which remained higher intraoperatively (α-power: Mid: -2.12 dB vs. noMid: -6.10 dB; p = 0.024). CONCLUSION: Midazolam premedication alters the intraoperative EEG-spectrum in elderly patients. SIGNIFICANCE: This finding provides further evidence for the role of GABAergic activation in the induction of elevated, frontal α-power during general anesthesia. TRIAL REGISTRY NUMBER: NCT02265263. 23 September 2014. Principal investigator: Prof. Dr. med. Claudia Spies. (https://clinicaltrials.gov/ct2/show/NCT02265263).