91 research outputs found

    Controlled Fault-Tolerant Power Converters for Power Quality Enhancement

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    Power quality depends generally on the interaction of electrical power with electrical equipments. If electrical equipments operate correctly and reliably without being damaged or stressed, a suitable level of power quality is assured. On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, power quality is poor and probably the economical loss could be important like the technical one. In the scenario of the Distributed Generation, power quality issues will be moreover important because an higher dissemination of power conditioning equipment will be requested and this obviously increases the sources of vulnerability of the electrical system. In this paper fault tolerant power converters are considered as a viable solution of power quality problems and a suitable control algorithm of them is presented. The control proposed in the paper is based on the model of the power converter reformulated in terms of healthy leg binary variable and the paper shows how this control is able to save the aspect of power quality when the converter works in the linear range. The effectiveness of such an algorithm and of the fault tolerant power converters are finally verified by means of simulations

    Unexpected Hypertensive Pneumothorax after Digestive Upper Endoscopy: A Case Report

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    We report an unexpected massive left pneumothorax at the end of a digestive upper endoscopy without evidences of perforation or airway over-pressure. The possible air passage through a diaphragmatic failing is discussed

    Low central venous saturation predicts poor outcome in patients with brain injury after major trauma: a prospective observational study

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    BACKGROUND: Continuous monitoring of central venous oxygen saturation (ScvO(2)) has been proposed as a prognostic indicator in several pathological conditions, including cardiac diseases, sepsis, trauma. To our knowledge, no studies have evaluated ScvO(2 )in polytraumatized patients with brain injury so far. Thus, the aim of the present study was to assess the prognostic role of ScvO(2 )monitoring during first 24 hours after trauma in this patients' population. METHODS: This prospective, non-controlled study, carried out between April 2006 and March 2008, was performed in a higher level Trauma Center in Florence (Italy). In the study period, 121 patients affected by major brain injury after major trauma were recruited. Inclusion criteria were: 1. Glasgow Coma Scale (GCS) score ≀ 13; 2. an Injury Severity Score (ISS) ≄ 15. Exclusion criteria included: 1. pregnancy; 2. age < 14 years; 3. isolated head trauma; 4. death within the first 24 hours from the event; 5. the lack of ScvO(2 )monitoring within 2 hours from the trauma. Demographic and clinical data were collected, including Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), Simplified Acute Physiologic Score II (SAPS II), Marshall score. The worst values of lactate and ScvO(2 )within the first 24 hours from trauma, ICU length of stay (LOS), and 28-day mortality were recorded. RESULTS: Patients who deceased within 28 days showed higher age (53 ± 16.6 vs 43.8 ± 19.6, P = 0.043), ISS core (39.3 ± 14 vs 30.3 ± 10.1, P < 0.001), AIS score for head/neck (4.5 ± 0.7 vs 3.4 ± 1.2, P = 0.001), SAPS II score (51.3 ± 14.1 vs 42.5 ± 15, P = 0.014), Marshall Score (3.5 ± 0.7 vs 2.3 ± 0.7, P < 0.001) and arterial lactate concentration (3.3 ± 1.8 vs 6.7 ± 4.2, P < 0.001), than survived patients, whereas ScvO(2 )resulted significantly lower (66.7% ± 11.9 vs 70.1% ± 8.9 vs, respectively; P = 0.046). Patients with ScvO(2 )values ≀ 65% also showed higher 28-days mortality rate (31.3% vs 13.5%, P = 0.034), ICU LOS (28.5 ± 15.2 vs 16.6 ± 13.8, P < 0.001), and total hospital LOS (45.1 ± 20.8 vs 33.2 ± 24, P = 0.046) than patients with ScvO(2 )> 65%. CONCLUSION: ScvO(2 )value less than 65%, measured in the first 24 hours after admission in patients with major trauma and head injury, was associated with higher mortality and prolonged hospitalization

    Low central venous saturation predicts poor outcome in patients with brain injury after major trauma: a prospective observational study

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    Abstract Background Continuous monitoring of central venous oxygen saturation (ScvO2) has been proposed as a prognostic indicator in several pathological conditions, including cardiac diseases, sepsis, trauma. To our knowledge, no studies have evaluated ScvO2 in polytraumatized patients with brain injury so far. Thus, the aim of the present study was to assess the prognostic role of ScvO2 monitoring during first 24 hours after trauma in this patients' population. Methods This prospective, non-controlled study, carried out between April 2006 and March 2008, was performed in a higher level Trauma Center in Florence (Italy). In the study period, 121 patients affected by major brain injury after major trauma were recruited. Inclusion criteria were: 1. Glasgow Coma Scale (GCS) score ≀ 13; 2. an Injury Severity Score (ISS) ≄ 15. Exclusion criteria included: 1. pregnancy; 2. age 2 monitoring within 2 hours from the trauma. Demographic and clinical data were collected, including Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), Simplified Acute Physiologic Score II (SAPS II), Marshall score. The worst values of lactate and ScvO2 within the first 24 hours from trauma, ICU length of stay (LOS), and 28-day mortality were recorded. Results Patients who deceased within 28 days showed higher age (53 ± 16.6 vs 43.8 ± 19.6, P = 0.043), ISS core (39.3 ± 14 vs 30.3 ± 10.1, P 2 resulted significantly lower (66.7% ± 11.9 vs 70.1% ± 8.9 vs, respectively; P = 0.046). Patients with ScvO2 values ≀ 65% also showed higher 28-days mortality rate (31.3% vs 13.5%, P = 0.034), ICU LOS (28.5 ± 15.2 vs 16.6 ± 13.8, P 2 > 65%. Conclusion ScvO2 value less than 65%, measured in the first 24 hours after admission in patients with major trauma and head injury, was associated with higher mortality and prolonged hospitalization.</p

    Diagnosis of carotid arterial injury in major trauma using a modification of Memphis criteria

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    <p>Abstract</p> <p>Background</p> <p>Incidence of Blunt Cerebrovascular Injuries (BCVI) after head injury has been reported as 0.5-1% of all admissions for blunt trauma, with a high stroke and mortality rate. The purpose of this study is to evaluate if a modification of Memphis criteria could improve the rate of BCVI diagnosis.</p> <p>Methods</p> <p>Trauma patients consecutively admitted to Intensive Care Unit (ICU) from Jan 2008 to Oct 2009 were considered for the study. Memphis criteria comprehend: basilar skull fracture with involvement of the carotid canal, cervical spine fracture, neurological exam not explained by brain imaging, Horner's syndrome, LeFort II-III fractures, and neck soft tissue injury. As single criteria modification, we included all patients with petrous bone fracture, even without carotid canal involvement. In all patients at risk of BCVI, 64-slice angio-CT-scans was performed.</p> <p>Results</p> <p>During the study period, 266 patients were admitted to the ICU for blunt major trauma. Among them, 162 presented traumatic brain injury or cervical spine fracture. In accordance with the proposed modified-Memphis criteria, 53 patients showed risk factors for BCVI compared to 45 using the original Memphis criteria. Among the 53 patients, 6 resulted as having carotid lesions (2.2% of all blunt major traumas; one patient more than when using Memphis criteria). Anticoagulant therapy with low molecular weight heparin was administered in all patients. No stroke or hemorrhagic complications occurred. Clinical examination at 6-months showed no central neurological deficit.</p> <p>Conclusion</p> <p>A modification of a single criteria of Memphis screening protocol might permit the identification of a higher percentage of BCVI. Limited by sample size, this study needs to be validated.</p

    Feasibility of inter-hospital transportation using extra-corporeal membrane oxygenation (ECMO) support of patients affected by severe swine-flu(H1N1)-related ARDS

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    <p>Abstract</p> <p>Background</p> <p>To describe the organization of an ECMO-centre from triage by telephone to the phase of inter-hospital transportation with ECMO of patients affected by H1N1-induced ARDS, describing techniques and equipment used.</p> <p>Methods</p> <p>From September 2009 to January 2010, 18 patients with H1N1-induced ARDS were referred to our ECMO-centre from other hospitals. Six patients had contraindications to treatment with ECMO and remained in the local hospital. Twelve patients were transported to our centre and were included in this study. Four patients were transported on ECMO (Group A) and eight on conventional ventilation (Group B). The groups were compared on the basis of adverse events during transport, clinical characteristics and outcome.</p> <p>Results</p> <p>The PaO2/FiO2 ratio was lower in the patients of Group A (46.8 vs 89.7 [median]) despite the PEEP values being higher (15.0 vs 8.5 [median]). The Murray score was higher in Group A (3.50 vs 2.75 [median]). During the transfer there were no significant complications noted in Group A, whereas two patients in Group B were reported with hypoxia (SpO2 < 90%). One patient in Group A died. All the other patients of the two groups have been discharged from hospital.</p> <p>Conclusions</p> <p>The creation of an ECMO team, with various experts in the treatment of ARDS, assured a safe transfer of patients with severe hypoxia, over long distances, when in other cases they wouldn't have been be transportable.</p

    Sigh in patients with acute hypoxemic respiratory failure and acute respiratory distress syndrome: the PROTECTION pilot randomized clinical trial

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    Background: Sigh is a cyclic brief recruitment manoeuvre: previous physiological studies showed that its use could be an interesting addition to pressure support ventilation to improve lung elastance, decrease regional heterogeneity and increase release of surfactant. Research question: Is the clinical application of sigh during pressure support ventilation (PSV) feasible? Study design and methods: We conducted a multi-center non-inferiority randomized clinical trial on adult intubated patients with acute hypoxemic respiratory failure or acute respiratory distress syndrome undergoing PSV. Patients were randomized to the No Sigh group and treated by PSV alone, or to the Sigh group, treated by PSV plus sigh (increase of airway pressure to 30 cmH2Ofor 3 seconds once per minute) until day 28 or death or successful spontaneous breathing trial. The primary endpoint of the study was feasibility, assessed as non-inferiority (5% tolerance) in the proportion of patients failing assisted ventilation. Secondary outcomes included safety, physiological parameters in the first week from randomization, 28-day mortality and ventilator-free days. Results: Two-hundred fifty-eight patients (31% women; median age 65 [54-75] years) were enrolled. In the Sigh group, 23% of patients failed to remain on assisted ventilation vs. 30% in the No Sigh group (absolute difference -7%, 95%CI -18% to 4%; p=0.015 for non-inferiority). Adverse events occurred in 12% vs. 13% in Sigh vs. No Sigh (p=0.852). Oxygenation was improved while tidal volume, respiratory rate and corrected minute ventilation were lower over the first 7 days from randomization in Sigh vs. No Sigh. There was no significant difference in terms of mortality (16% vs. 21%, p=0.342) and ventilator-free days (22 [7-26] vs. 22 [3-25] days, p=0.300) for Sigh vs. No Sigh. Interpretation: Among hypoxemic intubated ICU patients, application of sigh was feasible and without increased risk

    An Ontological Approach to Inform HMI Designs for Minimizing Driver Distractions with ADAS

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    ADAS (Advanced Driver Assistance Systems) are in-vehicle systems designed to enhance driving safety and efficiency as well as comfort for drivers in the driving process. Recent studies have noticed that when Human Machine Interface (HMI) is not designed properly, an ADAS can cause distraction which would affect its usage and even lead to safety issues. Current understanding of these issues is limited to the context-dependent nature of such systems. This paper reports the development of a holistic conceptualisation of how drivers interact with ADAS and how such interaction could lead to potential distraction. This is done taking an ontological approach to contextualise the potential distraction, driving tasks and user interactions centred on the use of ADAS. Example scenarios are also given to demonstrate how the developed ontology can be used to deduce rules for identifying distraction from ADAS and informing future designs
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