Deep Neural Networks for ECG-Based Pulse Detection during Out-of-Hospital Cardiac Arrest

The automatic detection of pulse during out-of-hospital cardiac arrest (OHCA) is necessary for the early recognition of the arrest and the detection of return of spontaneous circulation (end of the arrest). The only signal available in every single defibrillator and valid for the detection of pulse is the electrocardiogram (ECG). In this study we propose two deep neural network (DNN) architectures to detect pulse using short ECG segments (5 s), i.e., to classify the rhythm into pulseless electrical activity (PEA) or pulse-generating rhythm (PR). A total of 3914 5-s ECG segments, 2372 PR and 1542 PEA, were extracted from 279 OHCA episodes. Data were partitioned patient-wise into training (80%) and test (20%) sets. The first DNN architecture was a fully convolutional neural network, and the second architecture added a recurrent layer to learn temporal dependencies. Both DNN architectures were tuned using Bayesian optimization, and the results for the test set were compared to state-of-the art PR/PEA discrimination algorithms based on machine learning and hand crafted features. The PR/PEA classifiers were evaluated in terms of sensitivity (Se) for PR, specificity (Sp) for PEA, and the balanced accuracy (BAC), the average of Se and Sp. The Se/Sp/BAC of the DNN architectures were 94.1%/92.9%/93.5% for the first one, and 95.5%/91.6%/93.5% for the second one. Both architectures improved the performance of state of the art methods by more than 1.5 points in BAC.This work was supported by: The Spanish Ministerio de Economía y Competitividad, TEC2015-64678-R, jointly with the Fondo Europeo de Desarrollo Regional (FEDER), UPV/EHU via GIU17/031 and the Basque Government through the grant PRE_2018_2_0260

Noninvasive Monitoring of Manual Ventilation during Out-of- Hospital Cardiopulmonary Resuscitation

Cardiopulmonary resuscitation (CPR) consisting of chest compressions and assisted ventilation is crucial to treat out-of-hospital cardiac arrest (OHCA). It is well reported that quality of manual ventilations, in terms of rate and volume, is suboptimal, with a high incidence of hyperventilation, which is linked to poor outcomes. The lack of a noninvasive technology to monitor ventilations during out-of-hospital CPR precludes feedback on ventilations to the rescuer, and it handicaps the evaluation of the effect of ventilations on the outcome of the patient. This chapter addresses the possibilities and challenges of monitoring the quality of manual ventilations in current defibrillators. Methods are proposed to monitor ventilations based on the thoracic impedance and the capnogram. These methods can be integrated in defibrillators used in both basic and advanced life support. The algorithms are described, and the accuracy of the methods to monitor the ventilation rate and the quality metrics of the ventilations is reported using real OHCA episodes. The accuracy and limitations of the methods as well as the implications of integrating them in the treatment of patients in cardiac arrest are discussed

A Machine Learning Model for the Prognosis of Pulseless Electrical Activity during Out-of-Hospital Cardiac Arrest

Pulseless electrical activity (PEA) is characterized by the disassociation of the mechanical and electrical activity of the heart and appears as the initial rhythm in 20–30% of out-of-hospital cardiac arrest (OHCA) cases. Predicting whether a patient in PEA will convert to return of spontaneous circulation (ROSC) is important because different therapeutic strategies are needed depending on the type of PEA. The aim of this study was to develop a machine learning model to differentiate PEA with unfavorable (unPEA) and favorable (faPEA) evolution to ROSC. An OHCA dataset of 1921 5s PEA signal segments from defibrillator files was used, 703 faPEA segments from 107 patients with ROSC and 1218 unPEA segments from 153 patients with no ROSC. The solution consisted of a signal-processing stage of the ECG and the thoracic impedance (TI) and the extraction of the TI circulation component (ICC), which is associated with ventricular wall movement. Then, a set of 17 features was obtained from the ECG and ICC signals, and a random forest classifier was used to differentiate faPEA from unPEA. All models were trained and tested using patientwise and stratified 10-fold cross-validation partitions. The best model showed a median (interquartile range) area under the curve (AUC) of 85.7(9.8)% and a balance accuracy of 78.8(9.8)% , improving the previously available solutions at more than four points in the AUC and three points in balanced accuracy. It was demonstrated that the evolution of PEA can be predicted using the ECG and TI signals, opening the possibility of targeted PEA treatment in OHCA.This work was supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades through Grant RTI2018-101475-BI00, jointly with the Fondo Europeo de Desarrollo Regional (FEDER), by the Basque Government through Grant IT1229-19 and Grant PRE2020_1_0177, and by the university of the Basque Country (UPV/EHU) under Grant COLAB20/01

Arquitecturas de aprendizaje profundo para la detección de pulso en la parada cardiaca extrahospitalaria utilizando el ECG

La detección de la presencia de pulso durante la parada cardiorrespiratoria extrahospitalaria es crucial para la supervivencia del paciente. Se ha demostrado que la toma manual del pulso no es muy fiable y que consume demasiado tiempo, por lo que es necesario desarrollar métodos automáticos que ayuden en la identificación del retorno de la circulación espontánea del paciente en parada. En este trabajo se propone utilizar técnicas de aprendizaje profundo para la discriminación automática de ritmos con pulso (PR) y sin pulso (PEA) utilizando solamente información proveniente del ECG. Se ha utilizado una base de datos que contiene 3914 segmentos de 5 segundos (3372 PR y 1542 PEA), que se dividieron en dos bases de datos con pacientes disjuntos para la optimización y evaluación de los métodos. Los mejores resultados se han obtenido utilizando una red neuronal profunda que contiene dos etapas de convolución y una etapa recurrente para la extracción de características y a continuación un clasificador. El modelo se evalúa en términos de sensibilidad (SE, porcentaje de PRs correctamente detectados) y especificidad (SP, proporción de PEAs correctamente detectados). Sobre la base de evaluación se obtuvieron una SE/SP de 94.2%/91.0%, por lo que puede concluirse que la detección automática del pulso utilizando sólo el ECG es viable mediante técnicas de aprendizaje profundo.Este trabajo ha recibido apoyo económico conjunto del Ministerio de Economía y Competitividad Español y del Fondo Europeo de Desarrollo Regional (FEDER) a través del proyecto (TEC2015-64678-R), de la Universidad del País Vasco/Euskal Herriko Unibertsitatea mediante la ayuda a grupos de investigación GIU17/031, y del Gobierno Vasco a través de la beca PRE_2017_1_0112

Solución Multietapa para Diagnóstico del Ritmo Cardíaco durante la Resucitación Cardiopulmonar

Las compresiones torácicas durante la terapia de resucitación cardiopulmonar (RCP) inducen artefactos en el ECG comprometiendo el diagnóstico de los algoritmos de análisis de ritmo. El objetivo de este trabajo es diseñar un método que diagnostique con precisión el ritmo durante la RCP evitando así tener que interrumpir la terapia. Para ello se diseñó un algoritmo multi-etapa (AME) que incluye dos filtros para la supresión del artefacto basados en un algoritmo recursivo de mínimos cuadrados (RLS), el algoritmo de análisis de ritmo de un desfibrilador comercial y un clasificador de ritmos basado en la pendiente del ECG. Se usó una base de datos compuesta por 87 ritmos desfibrilables y 285 no-desfibrilables adquiridos de pacientes en parada cardiorrespitatoria extra-hospitalaria. Para la optimización y validación de la solución AME los datos se dividieron aleatoriamente por pacientes en un conjunto de entrenamiento (70%) y otro de prueba (30%). Este proceso se repitió 500 veces para estimar la distribución estadística de la sensibilidad (Se), especificidad (Sp) y precisión (Acc) de la solución AME. Los valores medios (desviación estándar) de Se, Sp y Acc fueron 92.1% (6.0), 92.4% (2.9) y 92.2% (3.0), respectivamente. La solución mejora resultados anteriores por hasta 5 puntos de precisión

Towards the Prediction of Rearrest during Out-of-Hospital Cardiac Arrest

A secondary arrest is frequent in patients that recover spontaneous circulation after an out-of-hospital cardiac arrest (OHCA). Rearrest events are associated to worse patient outcomes, but little is known on the heart dynamics that lead to rearrest. The prediction of rearrest could help improve OHCA patient outcomes. The aim of this study was to develop a machine learning model to predict rearrest. A random forest classifier based on 21 heart rate variability (HRV) and electrocardiogram (ECG) features was designed. An analysis interval of 2 min after recovery of spontaneous circulation was used to compute the features. The model was trained and tested using a repeated cross-validation procedure, on a cohort of 162 OHCA patients (55 with rearrest). The median (interquartile range) sensitivity (rearrest) and specificity (no-rearrest) of the model were 67.3% (9.1%) and 67.3% (10.3%), respectively, with median areas under the receiver operating characteristics and the precision–recall curves of 0.69 and 0.53, respectively. This is the first machine learning model to predict rearrest, and would provide clinically valuable information to the clinician in an automated way.This work was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades through grant RTI2018-101475-BI00, jointly with the Fondo Europeo de Desarrollo Regional (FEDER), and by the Basque Government through grants IT1229-19, PRE_2019_2_0100 and PRE_2019_1_0262. A.I. receives research grants from the US National Institutes of Health (NIH)

Seinalearen prozesatze digitalaren erronkak kanpoko desfibrilagailu automatikoaren inguruan

Bihotz-biriketako gelditzearen aurrean berpiztea honako bi ekintza nagusiren mendekoa da: bihotz-biriketako berpizte-masajea eta bentrikulu-erritmoaren desfibrilazioa, kanpoko desfibrilagailu automatiko baten bidez. Tresna horiek bihotzaren erritmo hilgarriak detektatzen dituzte pazientearen elektrokardiograma digitalki prozesatuz; ildo horretatik, azkeneko urteetan hiru erronka nabarmendu daitezke. Umeen (1 eta 8 urte bitartekoen) erritmoen sailkatze egokia lortzea da lehengoa. Bi sailkatze-parametro aurkezten eta ebaluatzen dira lan honetan. Horretarako, helduen eta umeen bihotz-erritmo desberdinez osatutako datu-basea aztertzen da, sentsibilitatea eta espezifikotasuna adinaren arabera neurtuz. Bigarrenak berpizte-masajea ematearekin batera analisi fidagarria egitea du helburu. Erreferentzia-seinaleak erabilita eta soilik elektrokardiograma erabilita, iragazketa moldakorrekin lortutako emaitzak konparatzen dira. Azkenik, hirugarren erronkaren inguruan, desfibrilazioaren arrakasta aurresateko metodoetara hurbilketa egiten da. Erronka horien guztien helburua bihotz-biriketako geldiunean dagoen gizakiaren bizi-aukera handitzea da

Seinalearen prozesatze digitalaren erronkak kanpoko desfibrilagailu automatikoaren inguruan

Bihotz-biriketako gelditzearen aurrean berpiztea honako bi ekintza nagusiren mendekoa da: bihotz-biriketako berpizte-masajea eta bentrikulu-erritmoaren desfibrilazioa, kanpoko desfibrilagailu automatiko baten bidez. Tresna horiek bihotzaren erritmo hilgarriak detektatzen dituzte pazientearen elektrokardiograma digitalki prozesatuz; ildo horretatik, azkeneko urteetan hiru erronka nabarmendu daitezke. Umeen (1 eta 8 urte bitartekoen) erritmoen sailkatze egokia lortzea da lehengoa. Bi sailkatze-parametro aurkezten eta ebaluatzen dira lan honetan. Horretarako, helduen eta umeen bihotz-erritmo desberdinez osatutako datu-basea aztertzen da, sentsibilitatea eta espezifikotasuna adinaren arabera neurtuz. Bigarrenak berpizte-masajea ematearekin batera analisi fidagarria egitea du helburu. Erreferentzia-seinaleak erabilita eta soilik elektrokardiograma erabilita, iragazketa moldakorrekin lortutako emaitzak konparatzen dira. Azkenik, hirugarren erronkaren inguruan, desfibrilazioaren arrakasta aurresateko metodoetara hurbilketa egiten da. Erronka horien guztien helburua bihotz-biriketako geldiunean dagoen gizakiaren bizi-aukera handitzea da

Analysis of Few-Shot Techniques for Fungal Plant Disease Classification and Evaluation of Clustering Capabilities Over Real Datasets

Plant fungal diseases are one of the most important causes of crop yield losses. Therefore, plant disease identification algorithms have been seen as a useful tool to detect them at early stages to mitigate their effects. Although deep-learning based algorithms can achieve high detection accuracies, they require large and manually annotated image datasets that is not always accessible, specially for rare and new diseases. This study focuses on the development of a plant disease detection algorithm and strategy requiring few plant images (Few-shot learning algorithm). We extend previous work by using a novel challenging dataset containing more than 100,000 images. This dataset includes images of leaves, panicles and stems of five different crops (barley, corn, rape seed, rice, and wheat) for a total of 17 different diseases, where each disease is shown at different disease stages. In this study, we propose a deep metric learning based method to extract latent space representations from plant diseases with just few images by means of a Siamese network and triplet loss function. This enhances previous methods that require a support dataset containing a high number of annotated images to perform metric learning and few-shot classification. The proposed method was compared over a traditional network that was trained with the cross-entropy loss function. Exhaustive experiments have been performed for validating and measuring the benefits of metric learning techniques over classical methods. Results show that the features extracted by the metric learning based approach present better discriminative and clustering properties. Davis-Bouldin index and Silhouette score values have shown that triplet loss network improves the clustering properties with respect to the categorical-cross entropy loss. Overall, triplet loss approach improves the DB index value by 22.7% and Silhouette score value by 166.7% compared to the categorical cross-entropy loss model. Moreover, the F-score parameter obtained from the Siamese network with the triplet loss performs better than classical approaches when there are few images for training, obtaining a 6% improvement in the F-score mean value. Siamese networks with triplet loss have improved the ability to learn different plant diseases using few images of each class. These networks based on metric learning techniques improve clustering and classification results over traditional categorical cross-entropy loss networks for plant disease identification.This project was partially supported by the Spanish Government through CDTI Centro para el Desarrollo Tecnológico e Industrial project AI4ES (ref CER-20211030), by the University of the Basque Country (UPV/EHU) under grant COLAB20/01 and by the Basque Government through grant IT1229-19