29 research outputs found

    Discrete-Event Systems in a Dioid Framework: Control Theory

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    Reanimatie na trauma

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    - Recent literature shows increased survival for patients with traumatic cardiac arrest.- An early and aggressive approach to underlying causes and good integrated trauma care are probably responsible for this.- The new resuscitation guideline of the European Resuscitation Council emphasises that treatment of the underlying cause deserves more priority than performing chest compressions.- In addition to a structured approach with interventions focused on the causes of the arrest, standard operating procedures and protocols, regular scenario training and clinical governance are vital to improve survival chances for these patient

    Diagnostic accuracy of a step-up imaging strategy in pediatric patients with blunt abdominal trauma

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    Blunt abdominal trauma (BAT) is an important but often unrecognized cause of death in children. Imaging plays a vital role in the early detection of abdominal trauma. The exact role of imaging in the management of BAT in children is still under research. The aim of this study was to assess diagnostic accuracy of a step-up imaging strategy, where the decision to observe or to perform an intervention depends on the vital parameters of the patient, in combination with the presence or absence of free fluid at Focused Assessment with Sonography for Trauma (FAST) and the findings on CT (performed selectively), for pediatric patients presenting to the ED with a blunt abdominal trauma. Consecutive patients aged ≤ 16 years admitted between January 2008 and December 2012 to a Dutch level 1 trauma centre were included in this retrospective study. Sensitivity, negative predictive value (NPV) and the negative likelihood ratio (LR-) of the imaging strategy were calculated. The cohort consisted of 122 patients; 66 (54%) patients were discharged home after primary survey, 51 (41%) patients were admitted and observed, 3 (2%) patients underwent transarterial embolization and 2 (2%) patients underwent surgery. Treatment failed in 1 patient, initially selected for observation. The sensitivity of the imaging strategy was 0.833 (0.446-0.990). The NPV and LR- were 0.991 (0.963-1.000) and 0.167 (0.028-0.997), respectively. The step-up imaging strategy that is applied in our academic level 1 trauma centre has a high sensitivity and a high negative predictive value. No clinically relevant injuries were missed without doing unnecessary harm, e.g. radiation or an interventio

    Systems biology towards life in silico: mathematics of the control of living cells.

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    Systems Biology is the science that aims to understand how biological function absent from macromolecules in isolation, arises when they are components of their system. Dedicated to the memory of Reinhart Heinrich, this paper discusses the origin and evolution of the new part of systems biology that relates to metabolic and signal-transduction pathways and extends mathematical biology so as to address postgenomic experimental reality. Various approaches to modeling the dynamics generated by metabolic and signal-transduction pathways are compared. The silicon cell approach aims to describe the intracellular network of interest precisely, by numerically integrating the precise rate equations that characterize the ways macromolecules' interact with each other. The non-equilibrium thermodynamic or 'lin-log' approach approximates the enzyme rate equations in terms of linear functions of the logarithms of the concentrations. Biochemical Systems Analysis approximates in terms of power laws. Importantly all these approaches link system behavior to molecular interaction properties. The latter two do this less precisely but enable analytical solutions. By limiting the questions asked, to optimal flux patterns, or to control of fluxes and concentrations around the (patho)physiological state, Flux Balance Analysis and Metabolic/Hierarchical Control Analysis again enable analytical solutions. Both the silicon cell approach and Metabolic/Hierarchical Control Analysis are able to highlight where and how system function derives from molecular interactions. The latter approach has also discovered a set of fundamental principles underlying the control of biological systems. The new law that relates concentration control to control by time is illustrated for an important signal transduction pathway, i.e. nuclear hormone receptor signaling such as relevant to bone formation. It is envisaged that there is much more Mathematical Biology to be discovered in the area between molecules and Life

    Routine contrast enema prior to stoma reversal seems only required following treatment for necrotizing enterocolitis: An evaluation of the diagnostic accuracy of the contrast enema

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    Introduction: Contrast enemas are often made prior to stoma reversal in order to detect distal intestinal strictures distal of the stoma. If untreated these strictures can cause obstruction which might necessitate redo-surgery. However, the value of contrast enemas is unclear. Therefore, we aim to evaluate the contrast enema's diagnostic accuracy in detecting strictures in children with a stoma. Methods: Young children (≤3 years) treated with a stoma between 1998 and 2018 were retrospectively included. The STARD criteria were followed. Patients treated for anorectal malformations and those that died before stoma reversal were excluded. Surgical identification of strictures during reversal or redo-surgery within three months was used as gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC) reflected diagnostic accuracy. Results: In 224 included children, strictures were found during reversal in 10% of which 95% in patients treated for necrotizing enterocolitis. Contrast enema was performed in 68% of all patients and detected 92% of the strictures. In the overall cohort, the sensitivity was 100%, specificity 98%, PPV 88% and NPV 100% whilst the AUC was 0.98. In patients treated for NEC, the sensitivity was 100%, specificity 97%, PPV 88% and NPV 100% whilst the AUC was 0.98. Conclusion: Strictures prior to stoma reversal seem to be mainly identified in patients treated for NEC and not in other diseases necessitating a stoma. Moreover, the contrast enema shows excellent diagnostic accuracy in detecting these strictures. For this reason we advise to only perform contrast enemas in patients treated for NEC. Level of Evidence: I

    The incidence of negative intraoperative findings after unsuccessful hydrostatic reduction of ileocolic intussusception in children: A retrospective analysis

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    Background: There is a lack of studies addressing the occurrence of negative intraoperative findings (that is the absence of intussusception) after an unsuccessful hydrostatic reduction of an ileocolic intussusception. The aim of this study is to determine the incidence of negative intraoperative findings after unsuccessful hydrostatic reduction of ileocolic intussusception. Methods: We conducted a multicentre retrospective study of all children aged 0–18 years treated for ileocolic intussusception from January 1, 2010 to December 31, 2015 in 9 Dutch hospitals. Primary outcome measure was the percentage of children without an intussusception during surgical exploration after unsuccessful hydrostatic reduction. Results: In the study period 436 patients were diagnosed with an ileocolic intussusception. Of these, 408 patients underwent hydrostatic reduction of an ileocolic intussusception. 112 patients (27.5%) underwent surgery after an unsuccessful hydrostatic reduction. In 13 (11.6%) patients no intraoperative evidence of intussusception was found. Patients who underwent surgical intervention after unsuccessful hydrostatic reduction were significantly younger than patients who had a successful hydrostatic reduction; there was no gender difference. Conclusion: A substantial number of children (11.6%) underwent a laparotomy after unsuccessful hydrostatic reduction in whom no intussusception was found intraoperatively. We suggest initiating laparoscopy instead of laparotomy when surgery is necessary. Level of evidence: Level II

    The incidence of negative intraoperative findings after unsuccessful hydrostatic reduction of ileocolic intussusception in children:A retrospective analysis

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    Background: There is a lack of studies addressing the occurrence of negative intraoperative findings (that is the absence of intussusception) after an unsuccessful hydrostatic reduction of an ileocolic intussusception. The aim of this study is to determine the incidence of negative intraoperative findings after unsuccessful hydrostatic reduction of ileocolic intussusception. Methods: We conducted a multicentre retrospective study of all children aged 0-18 years treated for ileocolic intussusception from January 1, 2010 to December 31, 2015 in 9 Dutch hospitals. Primary outcome measure was the percentage of children without an intussusception during surgical exploration after unsuccessful hydrostatic reduction. Results: In the study period 436 patients were diagnosed with an ileocolic intussusception. Of these, 408 patients underwent hydrostatic reduction of an ileocolic intussusception. 112 patients (27.5%) underwent surgery after an unsuccessful hydrostatic reduction. In 13 (11.6%) patients no intraoperative evidence of intussusception was found. Patients who underwent surgical intervention after unsuccessful hydrostatic reduction were significantly younger than patients who had a successful hydrostatic reduction: there was no gender difference. Conclusion: A substantial number of children (11.6%) underwent a laparotomy after unsuccessful hydrostatic reduction in whom no intussusception was found intraoperatively. We suggest initiating laparoscopy instead of laparotomy when surgery is necessary. (C) 2018 Elsevier Inc. All rights reserved
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