Estimating the Potential Speedup of Computer Vision Applications on Embedded Multiprocessors

Computer vision applications constitute one of the key drivers for embedded multicore architectures. Although the number of available cores is increasing in new architectures, designing an application to maximize the utilization of the platform is still a challenge. In this sense, parallel performance prediction tools can aid developers in understanding the characteristics of an application and finding the most adequate parallelization strategy. In this work, we present a method for early parallel performance estimation on embedded multiprocessors from sequential application traces. We describe its implementation in Parana, a fast trace-driven simulator targeting OpenMP applications on the STMicroelectronics' STxP70 Application-Specific Multiprocessor (ASMP). Results for the FAST key point detector application show an error margin of less than 10% compared to the reference cycle-approximate simulator, with lower modeling effort and up to 20x faster execution time.Comment: Presented at DATE Friday Workshop on Heterogeneous Architectures and Design Methods for Embedded Image Systems (HIS 2015) (arXiv:1502.07241

Application-level Performance Optimization: A Computer Vision Case Study on STHORM

AbstractComputer vision applications constitute one of the key drivers for embedded many-core architectures. In order to exploit the full potential of such systems, a balance between computation and communication is critical, but many computer vision algorithms present a highly data-dependent behavior that complexifies this task. To enable application performance optimization, the development environment must provide the developer with tools for fast and precise application-level performance analysis. We describe the process to port and optimize a face detection application onto the STHORM many-core accelerator using the STHORM OpenCL SDK. We identify the main factors that limit performance and discern the contributions arising from: the application itself, the OpenCL programming model, and the STHORM OpenCL SDK. Finally, we show how these issues can be addressed in the future to enable developers to further improve application performance

Healthcare-associated infections in patients with severe COVID-19 supported with extracorporeal membrane oxygenation: a nationwide cohort study

International audienceBackground Both critically ill patients with coronavirus disease 2019 (COVID-19) and patients receiving extracorporeal membrane oxygenation (ECMO) support exhibit a high incidence of healthcare-associated infections (HAI). However, data on incidence, microbiology, resistance patterns, and the impact of HAI on outcomes in patients receiving ECMO for severe COVID-19 remain limited. We aimed to report HAI incidence and microbiology in patients receiving ECMO for severe COVID-19 and to evaluate the impact of ECMO-associated infections (ECMO-AI) on in-hospital mortality. Methods For this study, we analyzed data from 701 patients included in the ECMOSARS registry which included COVID-19 patients supported by ECMO in France. Results Among 602 analyzed patients for whom HAI and hospital mortality data were available, 214 (36%) had ECMO-AI, resulting in an incidence rate of 27 ECMO-AI per 1000 ECMO days at risk. Of these, 154 patients had bloodstream infection (BSI) and 117 patients had ventilator-associated pneumonia (VAP). The responsible microorganisms were Enterobacteriaceae (34% for BSI and 48% for VAP), Enterococcus species (25% and 6%, respectively) and non-fermenting Gram-negative bacilli (13% and 20%, respectively). Fungal infections were also observed (10% for BSI and 3% for VAP), as were multidrug-resistant organisms (21% and 15%, respectively). Using a Cox multistate model, ECMO-AI were not found associated with hospital death (HR = 1.00 95% CI [0.79–1.26], p = 0.986). Conclusions In a nationwide cohort of COVID-19 patients receiving ECMO support, we observed a high incidence of ECMO-AI. ECMO-AI were not found associated with hospital death. Trial registration number NCT04397588 (May 21, 2020)

Bleeding and thrombotic events in patients with severe COVID-19 supported with extracorporeal membrane oxygenation: a nationwide cohort study

International audiencePurpose: To describe bleeding and thrombotic events and their risk factors in patients receiving extracorporeal membrane oxygenation (ECMO) for severe coronavirus disease 2019 (COVID-19) and to evaluate their impact on in-hospital mortality.Methods: The ECMOSARS registry included COVID-19 patients supported by ECMO in France. We analyzed all patients included up to March 31, 2022 without missing data regarding bleeding and thrombotic events. The association of bleeding and thrombotic events with in-hospital mortality and pre-ECMO variables was assessed using multivariable logistic regression models.Results: Among 620 patients supported by ECMO, 29% had only bleeding events, 16% only thrombotic events and 20% both bleeding and thrombosis. Cannulation site (18% of patients), ear nose and throat (12%), pulmonary bleeding (9%) and intracranial hemorrhage (8%) were the most frequent bleeding types. Device-related thrombosis and pulmonary embolism/thrombosis accounted for most of thrombotic events. In-hospital mortality was 55.7%. Bleeding events were associated with in-hospital mortality (adjusted odds ratio (adjOR) = 2.91[1.94-4.4]) but not thrombotic events (adjOR = 1.02[0.68-1.53]). Intracranial hemorrhage was strongly associated with in-hospital mortality (adjOR = 13.5[4.4-41.5]). Ventilation duration before ECMO ≥ 7 days and length of ECMO support were associated with bleeding. Thrombosis-associated factors were fibrinogen ≥ 6 g/L and length of ECMO support.Conclusions: In a nationwide cohort of COVID-19 patients supported by ECMO, bleeding incidence was high and associated with mortality. Intracranial hemorrhage incidence was higher than reported for non-COVID patients and carried the highest risk of death. Thrombotic events were less frequent and not associated with mortality. Length of ECMO support was associated with a higher risk of both bleeding and thrombosis, supporting the development of strategies to minimize ECMO duration

Veno-Arterial Extracorporeal Membrane Oxygenation for Circulatory Failure in COVID-19 Patients: Insights from the ECMOSARS Registry

International audienceObjectives: The clinical profile and outcomes of patients with Covid-19 who require veno-arterial or veno-venous-arterial extracorporeal membrane oxygenation (VA-ECMO - VAV-ECMO) are poorly understood. We aimed to describe the characteristics and outcomes of these patients and to identify predictors of both favorable and unfavorable outcomes.Methods: ECMOSARS is a multicenter, prospective, nationwide French registry enrolling patients who require VV/VA-ECMO in the context of Covid-19 infection (652 patients at 41 centers). We focused on 47 patients supported with VA- or VAV-ECMO for refractory cardiogenic shock.Results: Median age was 49. 14% of patients had a prior diagnosis of heart failure. The most common etiologies of cardiogenic shock were acute pulmonary embolism (30%), myocarditis (28%), and acute coronary syndrome (4%). E-CPR (Extracorporeal Cardiopulmonary Resuscitation) occurred in 38%. In-hospital survival was 28% in the whole cohort, and 43% when E-CPR patients were excluded. ECMO cannulation was associated with significant improvements in pH and FiO2 on day one, but non-survivors showed significantly more severe acidosis and higher FiO2 than survivors at this point (p = 0.030 and p = 0.006). Other factors associated with death were greater age (p = 0.02), higher BMI (p = 0.03), E-CPR (p = 0.001), non-myocarditis etiology (p = 0.02), higher serum lactates (p = 0.004), epinephrine (but not noradrenaline) use before initiation of ECMO (p = 0.003), hemorrhagic complications (p = 0.001), greater transfusion requirements (p = 0.001), and more severe SAVE and SAFE scores (p = 0.01 and p = 0.03).Conclusions: We report the largest focused analysis of VA- and VAV-ECMO recipients in Covid-19. Although relatively rare, the need for temporary mechanical circulatory support in these patients is associated with poor prognosis. However, VA-ECMO remains a viable solution to rescue carefully selected patients. We identified factors associated with poor prognosis and suggest that E-CPR is not a reasonable indication for VA-ECMO in this population