Time to Awakening and Self-Fulfilling Prophecies After Cardiac Arrest.

OBJECTIVES: Withdrawal of life-sustaining therapies for perceived poor neurologic prognosis (WLST-N) is common after resuscitation from cardiac arrest and may bias outcome estimates from models trained using observational data. We compared several approaches to outcome prediction with the goal of identifying strategies to quantify and reduce this bias. DESIGN: Retrospective observational cohort study. SETTING: Two academic medical centers ("UPMC" and "University of Alabama Birmingham" [UAB]). PATIENTS: Comatose adults resuscitated from cardiac arrest. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: As potential predictors, we considered clinical, laboratory, imaging, and quantitative electroencephalography data available early after hospital arrival. We followed patients until death, discharge, or awakening from coma. We used penalized Cox regression with a least absolute shrinkage and selection operator penalty and five-fold cross-validation to predict time to awakening in UPMC patients and then externally validated the model in UAB patients. This model censored patients after WLST-N, considering subsequent potential for awakening to be unknown. Next, we developed a penalized logistic model predicting awakening, which treated failure to awaken after WLST-N as a true observed outcome, and a separate logistic model predicting WLST-N. We scaled and centered individual patients' Cox and logistic predictions for awakening to allow direct comparison and then explored the difference in predictions across probabilities of WLST-N. Overall, 1,254 patients were included, and 29% awakened. Cox models performed well (mean area under the curve was 0.93 in the UPMC test sets and 0.83 in external validation). Logistic predictions of awakening were systematically more pessimistic than Cox-based predictions for patients at higher risk of WLST-N, suggesting potential for self-fulfilling prophecies to arise when failure to awaken after WLST-N is considered as the ground truth outcome. CONCLUSIONS: Compared with traditional binary outcome prediction, censoring outcomes after WLST-N may reduce potential for bias and self-fulfilling prophecies.

Comparing image search behaviour in the ARRS GoldMiner search engine and a clinical PACS/RIS.

Information search has changed the way we manage knowledge and the ubiquity of information access has made search a frequent activity, whether via Internet search engines or increasingly via mobile devices. Medical information search is in this respect no different and much research has been devoted to analyzing the way in which physicians aim to access information. Medical image search is a much smaller domain but has gained much attention as it has different characteristics than search for text documents. While web search log files have been analysed many times to better understand user behaviour, the log files of hospital internal systems for search in a PACS/RIS (Picture Archival and Communication System, Radiology Information System) have rarely been analysed. Such a comparison between a hospital PACS/RIS search and a web system for searching images of the biomedical literature is the goal of this paper. Objectives are to identify similarities and differences in search behaviour of the two systems, which could then be used to optimize existing systems and build new search engines. Log files of the ARRS GoldMiner medical image search engine (freely accessible on the Internet) containing 222,005 queries, and log files of Stanford's internal PACS/RIS search called radTF containing 18,068 queries were analysed. Each query was preprocessed and all query terms were mapped to the RadLex (Radiology Lexicon) terminology, a comprehensive lexicon of radiology terms created and maintained by the Radiological Society of North America, so the semantic content in the queries and the links between terms could be analysed, and synonyms for the same concept could be detected. RadLex was mainly created for the use in radiology reports, to aid structured reporting and the preparation of educational material (Lanlotz, 2006) [1]. In standard medical vocabularies such as MeSH (Medical Subject Headings) and UMLS (Unified Medical Language System) specific terms of radiology are often underrepresented, therefore RadLex was considered to be the best option for this task. The results show a surprising similarity between the usage behaviour in the two systems, but several subtle differences can also be noted. The average number of terms per query is 2.21 for GoldMiner and 2.07 for radTF, the used axes of RadLex (anatomy, pathology, findings, …) have almost the same distribution with clinical findings being the most frequent and the anatomical entity the second; also, combinations of RadLex axes are extremely similar between the two systems. Differences include a longer length of the sessions in radTF than in GoldMiner (3.4 and 1.9 queries per session on average). Several frequent search terms overlap but some strong differences exist in the details. In radTF the term "normal" is frequent, whereas in GoldMiner it is not. This makes intuitive sense, as in the literature normal cases are rarely described whereas in clinical work the comparison with normal cases is often a first step. The general similarity in many points is likely due to the fact that users of the two systems are influenced by their daily behaviour in using standard web search engines and follow this behaviour in their professional search. This means that many results and insights gained from standard web search can likely be transferred to more specialized search systems. Still, specialized log files can be used to find out more on reformulations and detailed strategies of users to find the right content.

Analyzing Medical Image Search Behavior: Semantics and Prediction of Query Results.

Log files of information retrieval systems that record user behavior have been used to improve the outcomes of retrieval systems, understand user behavior, and predict events. In this article, a log file of the ARRS GoldMiner search engine containing 222,005 consecutive queries is analyzed. Time stamps are available for each query, as well as masked IP addresses, which enables to identify queries from the same person. This article describes the ways in which physicians (or Internet searchers interested in medical images) search and proposes potential improvements by suggesting query modifications. For example, many queries contain only few terms and therefore are not specific; others contain spelling mistakes or non-medical terms that likely lead to poor or empty results. One of the goals of this report is to predict the number of results a query will have since such a model allows search engines to automatically propose query modifications in order to avoid result lists that are empty or too large. This prediction is made based on characteristics of the query terms themselves. Prediction of empty results has an accuracy above 88%, and thus can be used to automatically modify the query to avoid empty result sets for a user. The semantic analysis and data of reformulations done by users in the past can aid the development of better search systems, particularly to improve results for novice users. Therefore, this paper gives important ideas to better understand how people search and how to use this knowledge to improve the performance of specialized medical search engines.

Self-fulfilling prophecies and machine learning in resuscitation science.

INTRODUCTION: Growth of machine learning (ML) in healthcare has increased potential for observational data to guide clinical practice systematically. This can create self-fulfilling prophecies (SFPs), which arise when prediction of an outcome increases the chance that the outcome occurs. METHODS: We performed a scoping review, searching PubMed and ArXiv using terms related to machine learning, algorithmic fairness and bias. We reviewed results and selected manuscripts for inclusion based on expert opinion of well-designed or key studies and review articles. We summarized these articles to explore how use of ML can create, perpetuate or compound SFPs, and offer recommendations to mitigate these risks. RESULTS: We identify-four key mechanisms through which SFPs may be reproduced or compounded by ML. First, imperfect human beliefs and behavior may be encoded as SFPs when treatment decisions are not accounted for. Since patient outcomes are influenced by a myriad of clinical actions, many of which are not collected in data, this is common. Second, human-machine interaction may compound SFPs through a cycle of mutual reinforcement. Third, ML may introduce new SFPs stemming from incorrect predictions. Finally, historically correct clinical choices may become SFPs in the face of medical progress. CONCLUSION: There is a need for broad recognition of SFPs as ML is increasingly applied in resuscitation science and across medicine. Acknowledging this challenge is crucial to inform research and practice that can transform ML from a tool that risks obfuscating and compounding SFPs into one that sheds light on and mitigates SFPs.

Imputation Strategies Under Clinical Presence: Impact on Algorithmic Fairness.

Biases have marked medical history, leading to unequal care affecting marginalised groups. The patterns of missingness in observational data often reflect these group discrepancies, but the algorithmic fairness implications of group-specific missingness are not well understood. Despite its potential impact, imputation is too often an overlooked preprocessing step. When explicitly considered, attention is placed on overall performance, ignoring how this preprocessing can reinforce groupspecific inequities. Our work questions this choice by studying how imputation affects downstream algorithmic fairness. First, we provide a structured view of the relationship between clinical presence mechanisms and groupspecific missingness patterns. Then, through simulations and real-world experiments, we demonstrate that the imputation choice influences marginalised group performance and that no imputation strategy consistently reduces disparities. Importantly, our results show that current practices may endanger health equity as similarly performing imputation strategies at the population level can affect marginalised groups differently. Finally, we propose recommendations for mitigating inequities that may stem from a neglected step of the machine learning pipeline.

Sex differences in post cardiac arrest discharge locations.

BACKGROUND: We explored sex-based differences in discharge location after resuscitation from cardiac arrest. METHODS: We performed a single-center retrospective cohort study including patients hospitalized after resuscitation from cardiac arrest from January 2010 to May 2020. We identified patients from a prospective registry, from which we extracted standard demographic and clinical variables. We explored favorable discharge location, defined as discharge to home or acute rehabilitation for survivors to hospital discharge. We tested the association of sex with the residuals of a multivariable logistic regression built using bidirectional selection to control for clinically relevant covariates. RESULTS: We included 2,278 patients. Mean age was 59 (SD 16), 40% were women, and 77% were admitted after out-of-hospital cardiac arrest. A total of 970 patients (43%) survived to discharge; of those, 607 (63% of survivors) had a favorable discharge location. Female sex showed a weak independent association with unfavorable discharge location (adjusted OR 0.94 (95%CI 0.89-0.99)). CONCLUSIONS: Our results suggest a possible sex-based disparity in discharge location after cardiac arrest.

Predicting neurological recovery with Canonical Autocorrelation Embeddings.

Early prediction of the potential for neurological recovery after resuscitation from cardiac arrest is difficult but important. Currently, no clinical finding or combination of findings are sufficient to accurately predict or preclude favorable recovery of comatose patients in the first 24 to 48 hours after resuscitation. Thus, life-sustaining therapy is often continued for several days in patients whose irrecoverable injury is not yet recognized. Conversely, early withdrawal of life-sustaining therapy increases mortality among patients who otherwise might have gone on to recover. In this work, we present Canonical Autocorrelation Analysis (CAA) and Canonical Autocorrelation Embeddings (CAE), novel methods suitable for identifying complex patterns in high-resolution multivariate data often collected in highly monitored clinical environments such as intensive care units. CAE embeds sets of datapoints onto a space that characterizes their latent correlation structures and allows direct comparison of these structures through the use of a distance metric. The methodology may be particularly suitable when the unit of analysis is not just an individual datapoint but a dataset, as for instance in patients for whom physiological measures are recorded over time, and where changes of correlation patterns in these datasets are informative for the task at hand. We present a proof of concept to illustrate the potential utility of CAE by applying it to characterize electroencephalographic recordings from 80 comatose survivors of cardiac arrest, aiming to identify patients who will survive to hospital discharge with favorable functional recovery. Our results show that with very low probability of making a Type 1 error, we are able to identify 32.5% of patients who are likely to have a good neurological outcome, some of whom have otherwise unfavorable clinical characteristics. Importantly, some of these had 5% predicted chance of favorable recovery based on initial illness severity measures alone. Providing this information to support clinical decision-making could motivate the continuation of life-sustaining therapies for these patients.

Madres adolescentes y anticoncepción: tasas de continuación y eventos / Adolescent mothers and contraception

Hicimos una revisión retrospectiva de 503 adolescentes, que ingresaron a la Consulta de Planificación Familiar, durante el año 80, para evaluar su comportamiento ante el método anticonceptivo; hallamos una pérdida de seguimiento inicial del 22,4%. Las restantes, las clasificamos por edad en tres grupos: Grupo A (hasta 15 años), Grupo B (16 y 17 años) y Grupo C (18 y 19 años), correspondiendo el mayor volumen al Grupo C. El 95% de ellas habían tenido por lo menos un embarazo. El 90% usaban DIU y 9,85% gestágenos orales. El DIU más usado fue el inerte (Lippes) en 73,7%. Al universo en estudio se le aplicó la Tabla Tietze-Polter. La tasa de continuación general fue mejor con DIU que con G.O., tanto a los 12 meses como a los 18 meses, y más alta al aumentar la edad. El evento de mayor frecuencia fue la expulsión del DIU, siendo mayor la incidencia en las usuarias de inertes. El embarazo accidental fue más frecuente en las usuarias de DIU de cobre y en el Grupo B. Los retiros por razones médicas fueron parecidos en ambos DIU a los 12 meses y más frecuentes a los 18 en los de cobre. Hicimos comparaciones con autores nacionales y extranjeros. Presentamos las recomendaciones concernientes

Adolescencia y anticoncepción: Conocimiento, actitud y práctica / Adolescence and contraception: Knowledge, attitude and practice

Presentamos el resultado de 100 encuestas a adolescentes primiconsultantes de P.F. (hasta 19 años), quienes en su mayoría, el 90%, habían tenido algún embarazo, el 55% casadas, el 90% unidas, el 43,3% se unieron por el embarazo, el 71% se habían embarazado a los seis meses del inicio de V.S.A., más de la mitad eran estudiantes, y el 74% conocían los métodos anticonceptivos, aunque de éstas solo el 28,4% los usaban; casi la mitad, 47% no los usaban por deseo de embarazo, y la mayoría de ellas (72%) estaban dedicadas a labores del hogar en el momento de la entrevista. Luego hicimos una discusión y análisis de resultados concluyendo, al comparar nuestros resultados con otros trabajos, que no hay relación directa entre conocimiento y uso de métodos y que deben buscarse otras técnicas para promover el conocimiento y manejo de sexualidad y contracepción por los jóvenes

Adolescentes: anticoncepción y experiencia sexual / Adolescent: contraception and sexual experience

Se analizan 100 encuestas de adolescentes femeninas entre 14 y 19 años (promedio de 17,36), con el objetivo de evaluar conocimiento, actitud y práctica de métodos anticonceptivos. El 80 por ciento pertenecía a los estratos más pobres de la población; un 50 por ciento mantenían unión libre con su pareja sexual. La menarquia promedio fue de 12,14 años de edad promedio de primera relación sexual de 15,04. Un 80 por ciento había tenido un embarazo antes de asistir a la consulta de Planificación Familiar de la Maternidad Concepción Palacios. Más del 70 por ciento conocían algún método anticonceptivo al iniciarse sexualmente, pero el 90 por ciento tuvo su primera relación sexual sin protección. El 20 por ciento se embarazo en los 3 meses siguientes a la misma. Los métodos más conocidos y utilizados fueron anticonceptivos orales y los dispositivos intrauterinos