Jesús María Rodríguez Presedo

SUTIL: Intelligent ischemia monitoring system

SUTIL is an intelligent monitoring system for intensive and exhaustive follow up of patients in coronary care units. This system processes electrocardiographic and hemodynamic signals in real time, with the main objective of detecting ischemic episodes. In this paper, we describe the tasks included in SUTIL. In addition to basic tasks, those at higher levels will also be presented. Some of these latter tasks attempt to mimic, to some extent, the way in which the human expert operates.

Fuzzy modelling of the expert's knowledge in ECG-based ischaemia detection

Abstract We concentrate on computational implementations of the detection of ischaemic episodes in order to allow continuous monitoring of patients interned in Coronary Care Units (CCU). The consideration of several alternatives led us to choosing an implementation based on the experts knowledge as the most adequate. In order to solve the problem of transforming the imprecise knowledge provided by the expert into computable structures we have decided to make use of a fuzzy implementation. We illustrate and comment the operation of our solution over some records of the European ST-T Database, which is an electrocardiographic database specifically aimed at the validation of algorithms whose objective is the detection of ischaemic episodes. This work can be included in the more general problem of the design, physical implementation and validation of an electronic-computational system (SUTIL), which by means of the simultaneous, integrated and intelligent evaluation of a large amount of information extracted from real time processing of haemodynamic and electrocardiographic signals, performs an intensive and exhaustive follow up of patients with ischaemic cardiopathies interned in CCUs.

Particle filter robot localisation through robust fusion of laser, WiFi, compass, and a network of external cameras

Particle filter robot localisation fusing 2D laser, WiFi, compass and external cameras.Works with any sensor combination (even if unsynchronized or different data rates).Experiments in controlled situations and real operation in social events.Analysis and discussion of performance of each sensor and all sensor combinations.Best results obtained from the fusion of all the sensors (statistical significance). In this paper, we propose a multi-sensor fusion algorithm based on particle filters for mobile robot localisation in crowded environments. Our system is able to fuse the information provided by sensors placed on-board, and sensors external to the robot (off-board). We also propose a methodology for fast system deployment, map construction, and sensor calibration with a limited number of training samples. We validated our proposal experimentally with a laser range-finder, a WiFi card, a magnetic compass, and an external multi-camera network. We have carried out experiments that validate our deployment and calibration methodology. Moreover, we performed localisation experiments in controlled situations and real robot operation in social events. We obtained the best results from the fusion of all the sensors available: the precision and stability was sufficient for mobile robot localisation. No single sensor is reliable in every situation, but nevertheless our algorithm works with any subset of sensors: if a sensor is not available, the performance just degrades gracefully.

An Evaluation of Indexes as Support Tools in the Diagnosis of Sleep Apnea

This article evaluates several indexes as support tools to diagnose patients with Sleep Apnea-Hypopnea Syndrome (SAHS). Some of these indexes, such as the Apnea-Hypopnea Index, have been standardized and studied in depth in the literature. Other indexes are used extensively in the reports that commercial polysomnographs generate. However, they have not been studied in detail and clinicians have no standardized guidelines for interpreting them. Examples are the mean and maximum duration of apneas and hypopneas. Finally, several novel indexes proposed by the authors are also evaluated. To evaluate the indexes, we have used a database of 274 patients who have undergone a polysomnographic test. Several feature selection techniques were used to assess the capability of each index to discriminate between healthy and SAHS patients. The capability of the indexes for diagnosing the patients was analyzed by using decision trees which were trained using each index individually, and all the indexes together. Our results suggest that some indexes which are often present in the reports of commercial polysomnographs provide little or no information. On the other hand, other indexes that are usually not considered have a great capability to discern between SAHS and control patients.

A low cost screening test for Obstructive Sleep Apnea that can be performed at the patient's home

This paper presents a new screening test for Obstructive Sleep Apnea-Hypopnea (OSAH) Syndrome based on a PDA platform capable of recording the patients electrocardiogram during his/her nightly rest. OSAH patients present alterations in certain bands of the heart rate variability power spectrum. The more serious the disorder afflicting the patient it is, the greater these alterations are. An algorithm running on the PDA identifies the heart beats, and it calculates the RR intervals time series. Then the algorithm calculates an index that quantifies the magnitude of the heart rate variability power spectrum alterations, and therefore the severity of the patients condition. The reliability of this index has been validated using the Apnea-ECG Database. After the first night of use of the device at the patients home, the PDA communicates the test results to the hospital via the Internet using a WiFi connection, or through GPRS/UMTS. In the hospital, the physicians can decide whether the results are conclusive, or whether it is preferable to repeat the test. Sometimes it may be necessary to repeat the test just because one of the sensors of the electrocardiograph was disconnected during the night. This decision is communicated through the PDA to the patient, who then knows whether he/she should return the device, or if he/she should use it again the following night. The end result is a cheap and reliable OSAH screening test that neither involves a long waiting list nor requires an overnight stay in the hospital for a polysomnographic test.

An open platform for the protocolization of home medical supervision

This paper describes SERVANDO, a distributed open platform that deals with a series of recurrent problems in current telemedicine systems, particularly: (1) the scheduling of the different medical actions that should be executed, organized in a personalized agenda generated from a follow-up protocol; (2) functionality encapsulation and reuse in a set of services; (3) communications between the home of the patient and the hospital, through a flexible scheme for bidirectional message exchange; or (4) the management of the events generated during the monitoring. Supervision of patients is carried out through last generation smartphones. SERVANDO provides comprehensive facilities for generic telemedicine applications development, adaptable according to the disease and the particular characteristics of the patient. At the moment, with validation purposes, a follow-up protocol for the supervision of patients with chronic obstructive pulmonary disease has been implemented.

A proposal for the fuzzy evaluation of ischaemic episodes

The authors describe a method that permits the classification and later comparison of ischaemic episodes detected by a system for the automatic monitoring of patients. They want to obtain an evaluation of the seriousness of the episodes as a function of a set of factors, out of which, one of the most important is the existence of previous ischaemic episodes with a similar morphology. They have applied fuzzy techniques in mimicking in the best possible manner the way in which the human expert operates during the evaluation of these episodes.

Patient telemonitoring at home

One of the biggest problems in hospitals today is the increase of costs associated with the treatment of patients, especially in the case of the elderly. This trend makes it necessary to adopt new strategies in order to reduce such costs and, at the same time, maintain the high levels of care that are provided to patients. One way to reduce such costs is by moving patients to non-specialised areas or, if possible, to his/her home as soon as possible. In this paper we present a remote monitoring system capable of monitoring the state of a patient 24 hours a day, 7 days a week through the analysis of parameters extracted from the electrocardiographic signal (ECG) and reporting any anomaly to the hospital. One important feature of the system is its flexibility for providing users with access to monitoring information. In order to do so, the system is equipped with two complementary interfaces, being capable of giving integral access to monitoring information at any time, any place and from any location in an optimal manner.

Cycles of ECG parameter evolution during ischemic episodes

Presents a comparison between two different methods for analyzing ischemic episodes. Both methods are based on a beat by beat analysis of a large number of parameters. The authors process these data in order to extract information regarding the detection of meaningful cycles (presumably related to ischemic episodes) on ECG parameter evolution. In order to facilitate visual inspection of parameter evolution and thus facilitate the definition of criteria to detect such meaningful cycles, the authors apply a process for reducing the dimensionality of the parameter vector. To accomplish this task they employ both Principal Component Analysis (PCA) and Self-Organizing Maps (SOM). Considering a two dimensional output of these methods, the authors have observed that coinciding with ischemic episodes, a cycle starts moving away from a normality zone and moving back to that zone when the episode ends. As a preliminary result, the authors present graphic examples of these cycles over some of the records of the European ST-T Database.

Syntactic Characterization Of QRS Morphology

In this work we present a method for the morphological characterization of QRS complexes by means of a syntactic signal processing process. A grammar based on the criteria and definitions established by the Common Standards in Electrocardiography Working Party (CSE), and which permits a direct approximation to the analysis of the ECG signal performed by the expert is described.