212 research outputs found
FedSL: Federated Split Learning on Distributed Sequential Data in Recurrent Neural Networks
Federated Learning (FL) and Split Learning (SL) are privacy-preserving
Machine-Learning (ML) techniques that enable training ML models over data
distributed among clients without requiring direct access to their raw data.
Existing FL and SL approaches work on horizontally or vertically partitioned
data and cannot handle sequentially partitioned data where segments of
multiple-segment sequential data are distributed across clients. In this paper,
we propose a novel federated split learning framework, FedSL, to train models
on distributed sequential data. The most common ML models to train on
sequential data are Recurrent Neural Networks (RNNs). Since the proposed
framework is privacy preserving, segments of multiple-segment sequential data
cannot be shared between clients or between clients and server. To circumvent
this limitation, we propose a novel SL approach tailored for RNNs. A RNN is
split into sub-networks, and each sub-network is trained on one client
containing single segments of multiple-segment training sequences. During local
training, the sub-networks on different clients communicate with each other to
capture latent dependencies between consecutive segments of multiple-segment
sequential data on different clients, but without sharing raw data or complete
model parameters. After training local sub-networks with local sequential data
segments, all clients send their sub-networks to a federated server where
sub-networks are aggregated to generate a global model. The experimental
results on simulated and real-world datasets demonstrate that the proposed
method successfully train models on distributed sequential data, while
preserving privacy, and outperforms previous FL and centralized learning
approaches in terms of achieving higher accuracy in fewer communication rounds
Length of Stay prediction for Hospital Management using Domain Adaptation
Inpatient length of stay (LoS) is an important managerial metric which if
known in advance can be used to efficiently plan admissions, allocate resources
and improve care. Using historical patient data and machine learning
techniques, LoS prediction models can be developed. Ethically, these models can
not be used for patient discharge in lieu of unit heads but are of utmost
necessity for hospital management systems in charge of effective hospital
planning. Therefore, the design of the prediction system should be adapted to
work in a true hospital setting. In this study, we predict early hospital LoS
at the granular level of admission units by applying domain adaptation to
leverage information learned from a potential source domain. Time-varying data
from 110,079 and 60,492 patient stays to 8 and 9 intensive care units were
respectively extracted from eICU-CRD and MIMIC-IV. These were fed into a
Long-Short Term Memory and a Fully connected network to train a source domain
model, the weights of which were transferred either partially or fully to
initiate training in target domains. Shapley Additive exPlanations (SHAP)
algorithms were used to study the effect of weight transfer on model
explanability. Compared to the benchmark, the proposed weight transfer model
showed statistically significant gains in prediction accuracy (between 1% and
5%) as well as computation time (up to 2hrs) for some target domains. The
proposed method thus provides an adapted clinical decision support system for
hospital management that can ease processes of data access via ethical
committee, computation infrastructures and time
A Tree-based Federated Learning Approach for Personalized Treatment Effect Estimation from Heterogeneous Data Sources
Federated learning is an appealing framework for analyzing sensitive data
from distributed health data networks due to its protection of data privacy.
Under this framework, data partners at local sites collaboratively build an
analytical model under the orchestration of a coordinating site, while keeping
the data decentralized. However, existing federated learning methods mainly
assume data across sites are homogeneous samples of the global population,
hence failing to properly account for the extra variability across sites in
estimation and inference. Drawing on a multi-hospital electronic health records
network, we develop an efficient and interpretable tree-based ensemble of
personalized treatment effect estimators to join results across hospital sites,
while actively modeling for the heterogeneity in data sources through site
partitioning. The efficiency of our method is demonstrated by a study of causal
effects of oxygen saturation on hospital mortality and backed up by
comprehensive numerical results
An eICU/ICU Collaborative to Reduce Sepsis Mortality
Sepsis costs over 20 billion dollars annually to treat making it the most expensive diagnosis for hospitals (Afrefian, et al., 2017) and carries with it an average mortality rate of 45% (SCCM, 2016). The eICU/ICU collaborative project was developed to improve sepsis mortality at Sutter Health’s Solano hospital affiliate from 41.2% to the system-wide goal of 18.8% over the course of a year by implementing two technologies. The first was the onboarding of the non-invasive cardiac output monitoring (NICOM) technology by Sutter Solano to fulfill the 6-hour bundle compliance for septic shock resuscitation. The other technology was the activation and enhancement of the Core Measure Manager (CMM) high-quality data surveillance technology by Sutter’s eICU to screen all patients at Sutter Solano Medical Center for early identification and treatment of sepsis and septic shock. After twelve months of quality improvement measures including education, training, implementation, enhancement, tracking and treatment management; the dashboards revealed Sutter Solano’s sepsis/septic shock mortality rate dropped from 41.2% to 6.1%. Nurses and physicians need to recognize that central venous pressure (CVP) is no longer a recommended or accepted measure of hemodynamic stability. The latest evidence-based practice supports NICOM in conjunction with passive leg raise (PLR) as a foundational guideline for fluid resuscitation. The Clinical Nurse Leader (CNL), as systems analyst and risk anticipator, must manage information as well as the care environment to improve quality patient outcomes in the presence of evolving knowledge and the ever-changing healthcare system (AACN, 2013)
Soft Phenotyping for Sepsis via EHR Time-aware Soft Clustering
Sepsis is one of the most serious hospital conditions associated with high
mortality. Sepsis is the result of a dysregulated immune response to infection
that can lead to multiple organ dysfunction and death. Due to the wide
variability in the causes of sepsis, clinical presentation, and the recovery
trajectories identifying sepsis sub-phenotypes is crucial to advance our
understanding of sepsis characterization, identifying targeted treatments and
optimal timing of interventions, and improving prognostication. Prior studies
have described different sub-phenotypes of sepsis with organ-specific
characteristics. These studies applied clustering algorithms to electronic
health records (EHRs) to identify disease sub-phenotypes. However, prior
approaches did not capture temporal information and made uncertain assumptions
about the relationships between the sub-phenotypes for clustering procedures.
We develop a time-aware soft clustering algorithm guided by clinical context to
identify sepsis sub-phenotypes using data from the EHR. We identified six novel
sepsis hybrid sub-phenotypes and evaluated them for medical plausibility. In
addition, we built an early-warning sepsis prediction model using logistic
regression. Our results suggest that these novel sepsis hybrid sub-phenotypes
are promising to provide more precise information on the recovery trajectory
which can be important to inform management decisions and sepsis prognosis
Conditional survival with increasing duration of ICU admission: an observational study of three intensive care databases.
OBJECTIVES: Prolonged admissions to an ICU are associated with high resource utilization and personal cost to the patient. Previous reports suggest increasing length of stay may be associated with poor outcomes. Conditional survival represents the probability of future survival after a defined period of treatment on an ICU providing a description of how prognosis evolves over time. Our objective was to describe conditional survival as length of ICU stay increased. DESIGN: Retrospective observational cohort study of three large intensive care databases. SETTING: Three intensive care databases, two in the United States (Medical Information Mart for Intensive Care III and electronic ICU) and one in United Kingdom (Post Intensive Care Risk-Adjusted Alerting and Monitoring). PATIENTS: Index admissions to intensive care for patients 18 years or older. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 11,648, 38,532, and 165,125 index admissions were analyzed from Post Intensive Care Risk-Adjusted Alerting and Monitoring, Medical Information Mart for Intensive Care III and electronic ICU databases respectively. In all three cohorts, conditional survival declined over the first 5-10 days after ICU admission and changed little thereafter. In patients greater than or equal to 75 years old conditional survival continued to decline with increasing length of stay. CONCLUSIONS: After an initial period of 5-10 days, probability of future survival does not appear to decrease with increasing length of stay in unselected patients admitted to ICUs in United Kingdom and United States [corrected]. These findings were consistent between the three populations and suggest that a prolonged admission to an ICU is not a reason for a pessimism in younger patients but may indicate a poor prognosis in the older population
Representation Learning With Autoencoders For Electronic Health Records
Increasing volume of Electronic Health Records (EHR) in recent years provides great opportunities for data scientists to collaborate on different aspects of healthcare research by applying advanced analytics to these EHR clinical data. A key requirement however
is obtaining meaningful insights from high dimensional, sparse and complex clinical data. Data science approaches typically address this challenge by performing feature learning in order to build more reliable and informative feature representations from clinical data followed by supervised learning. In this research, we propose a predictive modeling approach based on deep feature representations and word embedding techniques. Our method uses different deep architectures (stacked sparse autoencoders, deep belief network, adversarial autoencoders and variational autoencoders) for feature representation in higher-level abstraction to obtain effective and robust features from EHRs, and then build prediction models on top of them. Our approach is particularly useful when the unlabeled data is abundant whereas labeled data is scarce. We investigate the performance of representation learning through a supervised learning approach. Our focus is to present a comparative study to evaluate the performance of different deep architectures through supervised learning and provide insights for the choice of deep feature representation techniques. Our experiments demonstrate that for small data sets, stacked sparse autoencoder demonstrates a superior generality performance in prediction due to sparsity regularization whereas variational autoencoders outperform the competing approaches for large data sets due to its capability of learning the representation distribution
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