Extracorporeal Membrane Oxygenation for Graft Dysfunction Early After Heart Transplantation: A Systematic Review and Meta-analysis.

INTRODUCTION: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a prevailing option for the management of severe early graft dysfunction. This systematic review and individual patient data (IPD) meta-analysis aims to evaluate (1) mortality, (2) rates of major complications, (3) prognostic factors, and (4) the effect of different VA-ECMO strategies on outcomes in adult heart transplant (HT) recipients supported with VA-ECMO. METHODS AND RESULTS: We conducted a systematic search and included studies of adults (≥18 years) who received VA-ECMO during their index hospitalization after HT and reported on mortality at any timepoint. We pooled data using random effects models. To identify prognostic factors, we analysed IPD using mixed effects logistic regression. We assessed the certainty in the evidence using the GRADE framework. We included 49 observational studies of 1477 patients who received VA-ECMO after HT, of which 15 studies provided IPD for 448 patients. There were no differences in mortality estimates between IPD and non-IPD studies. The short-term (30-day/in-hospital) mortality estimate was 33% (moderate certainty, 95% confidence interval [CI] 28%-39%) and 1-year mortality estimate 50% (moderate certainty, 95% CI 43%-57%). Recipient age (odds ratio 1.02, 95% CI 1.01-1.04) and prior sternotomy (OR 1.57, 95% CI 0.99-2.49) are associated with increased short-term mortality. There is low certainty evidence that early intraoperative cannulation and peripheral cannulation reduce the risk of short-term death. CONCLUSIONS: One-third of patients who receive VA-ECMO for early graft dysfunction do not survive 30 days or to hospital discharge, and one-half do not survive to 1 year after HT. Improving outcomes will require ongoing research focused on optimizing VA-ECMO strategies and care in the first year after HT.

Early bradycardia detection and therapeutic interventions in preterm infant monitoring.

In very preterm infants, cardio-respiratory events and associated hypoxemia occurring during early postnatal life have been associated with risks of retinopathy, growth alteration and neurodevelopment impairment. These events are commonly detected by continuous cardio-respiratory monitoring in neonatal intensive care units (NICU), through the associated bradycardia. NICU nurse interventions are mainly triggered by these alarms. In this work, we acquired data from 52 preterm infants during NICU monitoring, in order to propose an early bradycardia detector which is based on a decentralized fusion of three detectors. The main objective is to improve automatic detection under real-life conditions without altering performance with respect to that of a monitor commonly used in NICU. We used heart rate lower than 80 bpm during at least 10 sec to define bradycardia. With this definition we observed a high rate of false alarms (64%) in real-life and that 29% of the relevant alarms were not followed by manual interventions. Concerning the proposed detection method, when compared to current monitors, it provided a significant decrease of the detection delay of 2.9 seconds, without alteration of the sensitivity (97.6% vs 95.2%) and false alarm rate (63.7% vs 64.1%). We expect that such an early detection will improve the response of the newborn to the intervention and allow for the development of new automatic therapeutic strategies which could complement manual intervention and decrease the sepsis risk.

A multiformalism and multiresolution modelling environment: application to the cardiovascular system and its regulation.

The role of modelling and simulation in the systemic analysis of living systems is now clearly established. Emerging disciplines, such as systems biology, and worldwide research actions, such as the Physiome Project or the Virtual Physiological Human, are based on an intensive use of modelling and simulation methodologies and tools. One of the key aspects in this context is to perform an efficient integration of various models representing different biological or physiological functions, at different resolutions, spanning through different scales. This paper presents a multiformalism modelling and simulation environment (M2SL) that has been conceived to ease model integration. A given model is represented as a set of coupled and atomic model components that may be based on different mathematical formalisms with heterogeneous structural and dynamical properties. A co-simulation approach is used to solve these hybrid systems. The pioneering model of the overall regulation of the cardiovascular system proposed by Guyton and co-workers in 1972 has been implemented under M2SL and a pulsatile ventricular model based on a time-varying elastance has been integrated in a multi-resolution approach. Simulations reproducing physiological conditions and using different coupling methods show the benefits of the proposed environment.