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1.
PLoS One ; 19(4): e0300570, 2024.
Article En | MEDLINE | ID: mdl-38578822

OBJECTIVE: To create a data-driven definition of post-COVID conditions (PCC) by directly measure changes in symptomatology before and after a first COVID episode. MATERIALS AND METHODS: Retrospective cohort study using Optum® de-identified Electronic Health Record (EHR) dataset from the United States of persons of any age April 2020-September 2021. For each person with COVID (ICD-10-CM U07.1 "COVID-19" or positive test result), we selected up to 3 comparators. The final COVID symptom score was computed as the sum of new diagnoses weighted by each diagnosis' ratio of incidence in COVID group relative to comparator group. For the subset of COVID cases diagnosed in September 2021, we compared the incidence of PCC using our data-driven definition with ICD-10-CM code U09.9 "Post-COVID Conditions", first available in the US October 2021. RESULTS: The final cohort contained 588,611 people with COVID, with mean age of 48 years and 38% male. Our definition identified 20% of persons developed PCC in follow-up. PCC incidence increased with age: (7.8% of persons aged 0-17, 17.3% aged 18-64, and 33.3% aged 65+) and did not change over time (20.0% among persons diagnosed with COVID in 2020 versus 20.3% in 2021). For cases diagnosed in September 2021, our definition identified 19.0% with PCC in follow-up as compared to 2.9% with U09.9 code in follow-up. CONCLUSION: Symptom and U09.9 code-based definitions alone captured different populations. Maximal capture may consider a combined approach, particularly before the availability and routine utilization of specific ICD-10 codes and with the lack consensus-based definitions on the syndrome.


COVID-19 , Humans , Male , United States/epidemiology , Middle Aged , Female , COVID-19/epidemiology , Electronic Health Records , Post-Acute COVID-19 Syndrome , Retrospective Studies , International Classification of Diseases
2.
Crit Care Med ; 51(12): 1802-1811, 2023 12 01.
Article En | MEDLINE | ID: mdl-37855659

OBJECTIVES: To develop the International Cardiac Arrest Research (I-CARE), a harmonized multicenter clinical and electroencephalography database for acute hypoxic-ischemic brain injury research involving patients with cardiac arrest. DESIGN: Multicenter cohort, partly prospective and partly retrospective. SETTING: Seven academic or teaching hospitals from the United States and Europe. PATIENTS: Individuals 16 years old or older who were comatose after return of spontaneous circulation following a cardiac arrest who had continuous electroencephalography monitoring were included. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Clinical and electroencephalography data were harmonized and stored in a common Waveform Database-compatible format. Automated spike frequency, background continuity, and artifact detection on electroencephalography were calculated with 10-second resolution and summarized hourly. Neurologic outcome was determined at 3-6 months using the best Cerebral Performance Category (CPC) scale. This database includes clinical data and 56,676 hours (3.9 terabytes) of continuous electroencephalography data for 1,020 patients. Most patients died ( n = 603, 59%), 48 (5%) had severe neurologic disability (CPC 3 or 4), and 369 (36%) had good functional recovery (CPC 1-2). There is significant variability in mean electroencephalography recording duration depending on the neurologic outcome (range, 53-102 hr for CPC 1 and CPC 4, respectively). Epileptiform activity averaging 1 Hz or more in frequency for at least 1 hour was seen in 258 patients (25%) (19% for CPC 1-2 and 29% for CPC 3-5). Burst suppression was observed for at least 1 hour in 207 (56%) and 635 (97%) patients with CPC 1-2 and CPC 3-5, respectively. CONCLUSIONS: The I-CARE consortium electroencephalography database provides a comprehensive real-world clinical and electroencephalography dataset for neurophysiology research of comatose patients after cardiac arrest. This dataset covers the spectrum of abnormal electroencephalography patterns after cardiac arrest, including epileptiform patterns and those in the ictal-interictal continuum.


Coma , Heart Arrest , Humans , Adolescent , Coma/diagnosis , Retrospective Studies , Prospective Studies , Heart Arrest/diagnosis , Electroencephalography
3.
medRxiv ; 2023 Aug 28.
Article En | MEDLINE | ID: mdl-37693458

Objective: To develop a harmonized multicenter clinical and electroencephalography (EEG) database for acute hypoxic-ischemic brain injury research involving patients with cardiac arrest. Design: Multicenter cohort, partly prospective and partly retrospective. Setting: Seven academic or teaching hospitals from the U.S. and Europe. Patients: Individuals aged 16 or older who were comatose after return of spontaneous circulation following a cardiac arrest who had continuous EEG monitoring were included. Interventions: not applicable. Measurements and Main Results: Clinical and EEG data were harmonized and stored in a common Waveform Database (WFDB)-compatible format. Automated spike frequency, background continuity, and artifact detection on EEG were calculated with 10 second resolution and summarized hourly. Neurological outcome was determined at 3-6 months using the best Cerebral Performance Category (CPC) scale. This database includes clinical and 56,676 hours (3.9 TB) of continuous EEG data for 1,020 patients. Most patients died (N=603, 59%), 48 (5%) had severe neurological disability (CPC 3 or 4), and 369 (36%) had good functional recovery (CPC 1-2). There is significant variability in mean EEG recording duration depending on the neurological outcome (range 53-102h for CPC 1 and CPC 4, respectively). Epileptiform activity averaging 1 Hz or more in frequency for at least one hour was seen in 258 (25%) patients (19% for CPC 1-2 and 29% for CPC 3-5). Burst suppression was observed for at least one hour in 207 (56%) and 635 (97%) patients with CPC 1-2 and CPC 3-5, respectively. Conclusions: The International Cardiac Arrest Research (I-CARE) consortium database provides a comprehensive real-world clinical and EEG dataset for neurophysiology research of comatose patients after cardiac arrest. This dataset covers the spectrum of abnormal EEG patterns after cardiac arrest, including epileptiform patterns and those in the ictal-interictal continuum.

4.
Sci Rep ; 13(1): 10693, 2023 07 02.
Article En | MEDLINE | ID: mdl-37394559

Here, we investigate radiomics-based characterization of tumor vascular and microenvironmental properties in an orthotopic rat brain tumor model measured using dynamic-contrast-enhanced (DCE) MRI. Thirty-two immune compromised-RNU rats implanted with human U-251N cancer cells were imaged using DCE-MRI (7Tesla, Dual-Gradient-Echo). The aim was to perform pharmacokinetic analysis using a nested model (NM) selection technique to classify brain regions according to vasculature properties considered as the source of truth. A two-dimensional convolutional-based radiomics analysis was performed on the raw-DCE-MRI of the rat brains to generate dynamic radiomics maps. The raw-DCE-MRI and respective radiomics maps were used to build 28 unsupervised Kohonen self-organizing-maps (K-SOMs). A Silhouette-Coefficient (SC), k-fold Nested-Cross-Validation (k-fold-NCV), and feature engineering analyses were performed on the K-SOMs' feature spaces to quantify the distinction power of radiomics features compared to raw-DCE-MRI for classification of different Nested Models. Results showed that eight radiomics features outperformed respective raw-DCE-MRI in prediction of the three nested models. The average percent difference in SCs between radiomics features and raw-DCE-MRI was: 29.875% ± 12.922%, p < 0.001. This work establishes an important first step toward spatiotemporal characterization of brain regions using radiomics signatures, which is fundamental toward staging of tumors and evaluation of tumor response to different treatments.


Brain Neoplasms , Contrast Media , Humans , Rats , Animals , Brain Neoplasms/diagnostic imaging , Brain/diagnostic imaging , Algorithms , Magnetic Resonance Imaging/methods
5.
Neurology ; 101(9): e940-e952, 2023 08 29.
Article En | MEDLINE | ID: mdl-37414565

BACKGROUND AND OBJECTIVES: Epileptiform activity and burst suppression are neurophysiology signatures reflective of severe brain injury after cardiac arrest. We aimed to delineate the evolution of coma neurophysiology feature ensembles associated with recovery from coma after cardiac arrest. METHODS: Adults in acute coma after cardiac arrest were included in a retrospective database involving 7 hospitals. The combination of 3 quantitative EEG features (burst suppression ratio [BSup], spike frequency [SpF], and Shannon entropy [En]) was used to define 5 distinct neurophysiology states: epileptiform high entropy (EHE: SpF ≥4 per minute and En ≥5); epileptiform low entropy (ELE: SpF ≥4 per minute and <5 En); nonepileptiform high entropy (NEHE: SpF <4 per minute and ≥5 En); nonepileptiform low entropy (NELE: SpF <4 per minute and <5 En), and burst suppression (BSup ≥50% and SpF <4 per minute). State transitions were measured at consecutive 6-hour blocks between 6 and 84 hours after return of spontaneous circulation. Good neurologic outcome was defined as best cerebral performance category 1-2 at 3-6 months. RESULTS: One thousand thirty-eight individuals were included (50,224 hours of EEG), and 373 (36%) had good outcome. Individuals with EHE state had a 29% rate of good outcome, while those with ELE had 11%. Transitions out of an EHE or BSup state to an NEHE state were associated with good outcome (45% and 20%, respectively). No individuals with ELE state lasting >15 hours had good recovery. DISCUSSION: Transition to high entropy states is associated with an increased likelihood of good outcome despite preceding epileptiform or burst suppression states. High entropy may reflect mechanisms of resilience to hypoxic-ischemic brain injury.


Brain Injuries , Heart Arrest , Adult , Humans , Coma/complications , Retrospective Studies , Neurophysiology , Heart Arrest/complications , Electroencephalography , Brain Injuries/complications
6.
Sci Rep ; 13(1): 9672, 2023 06 14.
Article En | MEDLINE | ID: mdl-37316579

We introduce and validate four adaptive models (AMs) to perform a physiologically based Nested-Model-Selection (NMS) estimation of such microvascular parameters as forward volumetric transfer constant, Ktrans, plasma volume fraction, vp, and extravascular, extracellular space, ve, directly from Dynamic Contrast-Enhanced (DCE) MRI raw information without the need for an Arterial-Input Function (AIF). In sixty-six immune-compromised-RNU rats implanted with human U-251 cancer cells, DCE-MRI studies estimated pharmacokinetic (PK) parameters using a group-averaged radiological AIF and an extended Patlak-based NMS paradigm. One-hundred-ninety features extracted from raw DCE-MRI information were used to construct and validate (nested-cross-validation, NCV) four AMs for estimation of model-based regions and their three PK parameters. An NMS-based a priori knowledge was used to fine-tune the AMs to improve their performance. Compared to the conventional analysis, AMs produced stable maps of vascular parameters and nested-model regions less impacted by AIF-dispersion. The performance (Correlation coefficient and Adjusted R-squared for NCV test cohorts) of the AMs were: 0.914/0.834, 0.825/0.720, 0.938/0.880, and 0.890/0.792 for predictions of nested model regions, vp, Ktrans, and ve, respectively. This study demonstrates an application of AMs that quickens and improves DCE-MRI based quantification of microvasculature properties of tumors and normal tissues relative to conventional approaches.


Arteries , Magnetic Resonance Imaging , Humans , Animals , Rats , Microvessels/diagnostic imaging , Algorithms , Extracellular Space
7.
AMIA Jt Summits Transl Sci Proc ; 2023: 118-127, 2023.
Article En | MEDLINE | ID: mdl-37350898

Imaging examination selection and protocoling are vital parts of the radiology workflow, ensuring that the most suitable exam is done for the clinical question while minimizing the patient's radiation exposure. In this study, we aimed to develop an automated model for the revision of radiology examination requests using natural language processing techniques to improve the efficiency of pre-imaging radiology workflow. We extracted Musculoskeletal (MSK) magnetic resonance imaging (MRI) exam order from the radiology information system at Henry Ford Hospital in Detroit, Michigan. The pretrained transformer, "DistilBERT" was adjusted to create a vector representation of the free text within the orders while maintaining the meaning of the words. Then, a logistic regression-based classifier was trained to identify orders that required additional review. The model achieved 83% accuracy and had an area under the curve of 0.87.

8.
PLoS One ; 17(7): e0269752, 2022.
Article En | MEDLINE | ID: mdl-35877608

We study the relationships between the real-time psychophysiological activity of professional traders, their financial transactions, and market fluctuations. We collected multiple physiological signals such as heart rate, blood volume pulse, and electrodermal activity of 55 traders at a leading global financial institution during their normal working hours over a five-day period. Using their physiological measurements, we implemented a novel metric of trader's "psychophysiological activation" to capture affect such as excitement, stress and irritation. We find statistically significant relations between traders' psychophysiological activation levels and such as their financial transactions, market fluctuations, the type of financial products they traded, and their trading experience. We conducted post-measurement interviews with traders who participated in this study to obtain additional insights in the key factors driving their psychophysiological activation during financial risk processing. Our work illustrates that psychophysiological activation plays a prominent role in financial risk processing for professional traders.


Commerce , Psychophysiology , Heart Rate
9.
Front Digit Health ; 3: 608893, 2021.
Article En | MEDLINE | ID: mdl-34713090

Introduction: Developing reliable medication dosing guidelines is challenging because individual dose-response relationships are mitigated by both static (e. g., demographic) and dynamic factors (e.g., kidney function). In recent years, several data-driven medication dosing models have been proposed for sedatives, but these approaches have been limited in their ability to assess interindividual differences and compute individualized doses. Objective: The primary objective of this study is to develop an individualized framework for sedative-hypnotics dosing. Method: Using publicly available data (1,757 patients) from the MIMIC IV intensive care unit database, we developed a sedation management agent using deep reinforcement learning. More specifically, we modeled the sedative dosing problem as a Markov Decision Process and developed an RL agent based on a deep deterministic policy gradient approach with a prioritized experience replay buffer to find the optimal policy. We assessed our method's ability to jointly learn an optimal personalized policy for propofol and fentanyl, which are among commonly prescribed sedative-hypnotics for intensive care unit sedation. We compared our model's medication performance against the recorded behavior of clinicians on unseen data. Results: Experimental results demonstrate that our proposed model would assist clinicians in making the right decision based on patients' evolving clinical phenotype. The RL agent was 8% better at managing sedation and 26% better at managing mean arterial compared to the clinicians' policy; a two-sample t-test validated that these performance improvements were statistically significant (p < 0.05). Conclusion: The results validate that our model had better performance in maintaining control variables within their target range, thereby jointly maintaining patients' health conditions and managing their sedation.

10.
Crit Care Med ; 49(1): e91-e97, 2021 01 01.
Article En | MEDLINE | ID: mdl-33156121

OBJECTIVES: Sepsis is a life-threatening response to infection that causes tissue damage, organ failure, and death. Effective early prediction of sepsis would improve patients' diagnosis and reduce the cost associated with late-stage sepsis infection by applying appropriate early intervention. However, effective early prediction is challenging because sepsis biomarkers are neither obvious nor definitive, and sepsis datasets are heavily imbalanced against positive diagnosis of sepsis while containing significant missing values. Early prediction of sepsis in ICUs using clinical data is the objective of the PhysioNet/Computing in Cardiology Challenge 2019. DESIGN: In this article, we proposed a machine learning algorithm to aid in the early detection of sepsis. SETTING: We applied linear interpolation and implemented a sample weighted AdaBoost model to predict sepsis 6 hours before clinical diagnosis. PATIENTS: Medical data contains more than 40,000 patients gathered from three geographically distinct U.S. hospital systems that consisted of a combination of hourly vital sign, lab values, and static patient descriptions. INTERVENTIONS: The challenge metric, however, did not directly reward models for their generalizability across institutions. MEASUREMENTS AND MAIN RESULTS: The article is evaluated using a new metric called Utility Score that is defined as Official scoring criteria. Our approach was among the top 10% of entries to the Challenge on a hidden test set. CONCLUSIONS: Herein, we demonstrate that our proposed approach was the most effective of the Challenge entrants when such generalizability is explicitly accounted for in model evaluation.


Sepsis/diagnosis , Algorithms , Biomarkers , Early Diagnosis , Female , Humans , Intensive Care Units , Machine Learning , Male , Sepsis/pathology , Vital Signs
11.
Neurology ; 95(5): e563-e575, 2020 08 04.
Article En | MEDLINE | ID: mdl-32661097

OBJECTIVE: To determine cost-effectiveness parameters for EEG monitoring in cardiac arrest prognostication. METHODS: We conducted a cost-effectiveness analysis to estimate the cost per quality-adjusted life-year (QALY) gained by adding continuous EEG monitoring to standard cardiac arrest prognostication using the American Academy of Neurology Practice Parameter (AANPP) decision algorithm: neurologic examination, somatosensory evoked potentials, and neuron-specific enolase. We explored lifetime cost-effectiveness in a closed system that incorporates revenue back into the medical system (return) from payers who survive a cardiac arrest with good outcome and contribute to the health system during the remaining years of life. Good outcome was defined as a Cerebral Performance Category (CPC) score of 1-2 and poor outcome as CPC of 3-5. RESULTS: An improvement in specificity for poor outcome prediction of 4.2% would be sufficient to make continuous EEG monitoring cost-effective (baseline AANPP specificity = 83.9%). In sensitivity analysis, the effect of increased sensitivity on the cost-effectiveness of EEG depends on the utility (u) assigned to a poor outcome. For patients who regard surviving with a poor outcome (CPC 3-4) worse than death (u = -0.34), an increased sensitivity for poor outcome prediction of 13.8% would make AANPP + EEG monitoring cost-effective (baseline AANPP sensitivity = 76.3%). In the closed system, an improvement in sensitivity of 1.8% together with an improvement in specificity of 3% was sufficient to make AANPP + EEG monitoring cost-effective, assuming lifetime return of 50% (USD $70,687). CONCLUSION: Incorporating continuous EEG monitoring into cardiac arrest prognostication is cost-effective if relatively small improvements in sensitivity and specificity are achieved.


Cost-Benefit Analysis , Electroencephalography/economics , Heart Arrest/complications , Neurophysiological Monitoring/economics , Neurophysiological Monitoring/methods , Algorithms , Decision Trees , Humans , Prognosis , Seizures/diagnosis , Seizures/etiology , Sensitivity and Specificity
12.
Front Digit Health ; 2: 608920, 2020.
Article En | MEDLINE | ID: mdl-34713069

Electroencephalography (EEG) is used in the diagnosis, monitoring, and prognostication of many neurological ailments including seizure, coma, sleep disorders, brain injury, and behavioral abnormalities. One of the primary challenges of EEG data is its sensitivity to a breadth of non-stationary noises caused by physiological-, movement-, and equipment-related artifacts. Existing solutions to artifact detection are deficient because they require experts to manually explore and annotate data for artifact segments. Existing solutions to artifact correction or removal are deficient because they assume that the incidence and specific characteristics of artifacts are similar across both subjects and tasks (i.e., "one-size-fits-all"). In this paper, we describe a novel EEG noise-reduction method that uses representation learning to perform patient- and task-specific artifact detection and correction. More specifically, our method extracts 58 clinically relevant features and applies an ensemble of unsupervised outlier detection algorithms to identify EEG artifacts that are unique to a given task and subject. The artifact segments are then passed to a deep encoder-decoder network for unsupervised artifact correction. We compared the performance of classification models trained with and without our method and observed a 10% relative improvement in performance when using our approach. Our method provides a flexible end-to-end unsupervised framework that can be applied to novel EEG data without the need for expert supervision and can be used for a variety of clinical decision tasks, including coma prognostication and degenerative illness detection. By making our method, code, and data publicly available, our work provides a tool that is of both immediate practical utility and may also serve as an important foundation for future efforts in this domain.

13.
Clin Neurophysiol ; 130(10): 1908-1916, 2019 10.
Article En | MEDLINE | ID: mdl-31419742

OBJECTIVE: Electroencephalogram (EEG) reactivity is a robust predictor of neurological recovery after cardiac arrest, however interrater-agreement among electroencephalographers is limited. We sought to evaluate the performance of machine learning methods using EEG reactivity data to predict good long-term outcomes in hypoxic-ischemic brain injury. METHODS: We retrospectively reviewed clinical and EEG data of comatose cardiac arrest subjects. Electroencephalogram reactivity was tested within 72 h from cardiac arrest using sound and pain stimuli. A Quantitative EEG (QEEG) reactivity method evaluated changes in QEEG features (EEG spectra, entropy, and frequency features) during the 10 s before and after each stimulation. Good outcome was defined as Cerebral Performance Category of 1-2 at six months. Performance of a random forest classifier was compared against a penalized general linear model (GLM) and expert electroencephalographer review. RESULTS: Fifty subjects were included and sixteen (32%) had good outcome. Both QEEG reactivity methods had comparable performance to expert EEG reactivity assessment for good outcome prediction (mean AUC 0.8 for random forest vs. 0.69 for GLM vs. 0.69 for expert review, respectively; p non-significant). CONCLUSIONS: Machine-learning models utilizing quantitative EEG reactivity data can predict long-term outcome after cardiac arrest. SIGNIFICANCE: A quantitative approach to EEG reactivity assessment may support prognostication in cardiac arrest.


Electroencephalography/methods , Hypoxia-Ischemia, Brain/diagnosis , Hypoxia-Ischemia, Brain/physiopathology , Machine Learning , Adult , Aged , Female , Humans , Male , Middle Aged , Prognosis , Retrospective Studies
14.
Crit Care Med ; 47(10): 1416-1423, 2019 10.
Article En | MEDLINE | ID: mdl-31241498

OBJECTIVES: Electroencephalogram features predict neurologic recovery following cardiac arrest. Recent work has shown that prognostic implications of some key electroencephalogram features change over time. We explore whether time dependence exists for an expanded selection of quantitative electroencephalogram features and whether accounting for this time dependence enables better prognostic predictions. DESIGN: Retrospective. SETTING: ICUs at four academic medical centers in the United States. PATIENTS: Comatose patients with acute hypoxic-ischemic encephalopathy. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We analyzed 12,397 hours of electroencephalogram from 438 subjects. From the electroencephalogram, we extracted 52 features that quantify signal complexity, category, and connectivity. We modeled associations between dichotomized neurologic outcome (good vs poor) and quantitative electroencephalogram features in 12-hour intervals using sequential logistic regression with Elastic Net regularization. We compared a predictive model using time-varying features to a model using time-invariant features and to models based on two prior published approaches. Models were evaluated for their ability to predict binary outcomes using area under the receiver operator curve, model calibration (how closely the predicted probability of good outcomes matches the observed proportion of good outcomes), and sensitivity at several common specificity thresholds of interest. A model using time-dependent features outperformed (area under the receiver operator curve, 0.83 ± 0.08) one trained with time-invariant features (0.79 ± 0.07; p < 0.05) and a random forest approach (0.74 ± 0.13; p < 0.05). The time-sensitive model was also the best-calibrated. CONCLUSIONS: The statistical association between quantitative electroencephalogram features and neurologic outcome changed over time, and accounting for these changes improved prognostication performance.


Electroencephalography , Hypoxia-Ischemia, Brain/diagnosis , Acute Disease , Adult , Aged , Aged, 80 and over , Electroencephalography/trends , Evaluation Studies as Topic , Female , Humans , Intensive Care Units , Male , Middle Aged , Predictive Value of Tests , Prognosis , Recovery of Function , Retrospective Studies , Time Factors
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 4058-4064, 2018 Jul.
Article En | MEDLINE | ID: mdl-30441248

The judgment of intensive care unit (ICU) providers is difficult to measure using conventional structured electronic medical record (EMR) data. However, provider sentiment may be a proxy for such judgment. Utilizing 10 years of EMR data, this study evaluates the association between provider sentiment and diagnostic imaging utilization. We extracted daily positive / negative sentiment scores of written provider notes, and used a Poisson regression to estimate sentiment association with the total number of daily imaging reports. After adjusting for confounding factors, we found that (1) negative sentiment was associated with increased imaging utilization $(p < 0.01)$, (2) sentiment's association was most pronounced at the beginning of the ICU stay $(p < 0.01)$, and (3) the presence of any form of sentiment increased diagnostic imaging utilization up to a critical threshold $(p < 0.01)$. Our results indicate that provider sentiment may clarify currently unexplained variance in resource utilization and clinical practice.


Intensive Care Units , Physicians , Diagnostic Imaging , Electronic Health Records , Emotions , Humans
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 4927-4931, 2018 Jul.
Article En | MEDLINE | ID: mdl-30441448

Medication dosing in a critical care environment is a complex task that involves close monitoring of relevant physiologic and laboratory biomarkers and corresponding sequential adjustment of the prescribed dose. Misdosing of medications with narrow therapeutic windows (such as intravenous [IV] heparin) can result in preventable adverse events, decrease quality of care and increase cost. Therefore, a robust recommendation system can help clinicians by providing individualized dosing suggestions or corrections to existing protocols. We present a clinician-in-the-loop framework for adjusting IV heparin dose using deep reinforcement learning (RL). Our main objectives were to learn a new IV heparin dosing policy based on the multi-dimensional features of patients, and evaluate the effectiveness of the learned policy in the presence of other confounding factors that may contribute to heparin-related side effects. The data used in the experiments included 2598 intensive care patients from the publicly available MIMIC database and 2310 patients from the Emory University clinical data warehouse. Experimental results suggested that the distance from RL policy had a statistically significant association with anticoagulant complications $(p< 0.05)$, after adjusting for the effects of confounding factors.


Anticoagulants , Critical Care , Heparin , Humans , Intensive Care Units , Reinforcement, Psychology
17.
Crit Care Med ; 46(12): e1213-e1221, 2018 12.
Article En | MEDLINE | ID: mdl-30247243

OBJECTIVES: Absence of somatosensory evoked potentials is considered a nearly perfect predictor of poor outcome after cardiac arrest. However, reports of good outcomes despite absent somatosensory evoked potentials and high rates of withdrawal of life-sustaining therapies have raised concerns that estimates of the prognostic value of absent somatosensory evoked potentials may be biased by self-fulfilling prophecies. We aimed to develop an unbiased estimate of the false positive rate of absent somatosensory evoked potentials as a predictor of poor outcome after cardiac arrest. DATA SOURCES: PubMed. STUDY SELECTION: We selected 35 studies in cardiac arrest prognostication that reported somatosensory evoked potentials. DATA EXTRACTION: In each study, we identified rates of withdrawal of life-sustaining therapies and good outcomes despite absent somatosensory evoked potentials. We appraised studies for potential biases using the Quality in Prognosis Studies tool. Using these data, we developed a statistical model to estimate the false positive rate of absent somatosensory evoked potentials adjusted for withdrawal of life-sustaining therapies rate. DATA SYNTHESIS: Two-thousand one-hundred thirty-three subjects underwent somatosensory evoked potential testing. Five-hundred ninety-four had absent somatosensory evoked potentials; of these, 14 had good functional outcomes. The rate of withdrawal of life-sustaining therapies for subjects with absent somatosensory evoked potential could be estimated in 14 of the 35 studies (mean 80%, median 100%). The false positive rate for absent somatosensory evoked potential in predicting poor neurologic outcome, adjusted for a withdrawal of life-sustaining therapies rate of 80%, is 7.7% (95% CI, 4-13%). CONCLUSIONS: Absent cortical somatosensory evoked potentials do not infallibly predict poor outcome in patients with coma following cardiac arrest. The chances of survival in subjects with absent somatosensory evoked potentials, though low, may be substantially higher than generally believed.


Coma/diagnosis , Coma/physiopathology , Evoked Potentials, Somatosensory/physiology , Heart Arrest/physiopathology , Coma/etiology , False Positive Reactions , Heart Arrest/complications , Humans , Prognosis , Treatment Outcome , Withholding Treatment
18.
PLoS One ; 13(5): e0197226, 2018.
Article En | MEDLINE | ID: mdl-29750814

RATIONALE: Factors associated with one-year mortality after recovery from critical illness are not well understood. Clinicians generally lack information regarding post-hospital discharge outcomes of patients from the intensive care unit, which may be important when counseling patients and families. OBJECTIVE: We sought to determine which factors among patients who survived for at least 30 days post-ICU admission are associated with one-year mortality. METHODS: Single-center, longitudinal retrospective cohort study of all ICU patients admitted to a tertiary-care academic medical center from 2001-2012 who survived ≥30 days from ICU admission. Cox's proportional hazards model was used to identify the variables that are associated with one-year mortality. The primary outcome was one-year mortality. RESULTS: 32,420 patients met the inclusion criteria and were included in the study. Among patients who survived to ≥30 days, 28,583 (88.2%) survived for greater than one year, whereas 3,837 (11.8%) did not. Variables associated with decreased one-year survival include: increased age, malignancy, number of hospital admissions within the prior year, duration of mechanical ventilation and vasoactive agent use, sepsis, history of congestive heart failure, end-stage renal disease, cirrhosis, chronic obstructive pulmonary disease, and the need for renal replacement therapy. Numerous effect modifications between these factors were found. CONCLUSION: Among survivors of critical illness, a significant number survive less than one year. More research is needed to help clinicians accurately identify those patients who, despite surviving their acute illness, are likely to suffer one-year mortality, and thereby to improve the quality of the decisions and care that impact this outcome.


Heart Failure/mortality , Kidney Failure, Chronic/mortality , Mortality , Pulmonary Disease, Chronic Obstructive/mortality , Aged , Critical Care , Critical Illness , Disease-Free Survival , Female , Fibrosis , Heart Failure/therapy , Humans , Kidney Failure, Chronic/therapy , Longitudinal Studies , Male , Middle Aged , Pulmonary Disease, Chronic Obstructive/therapy , Renal Replacement Therapy , Retrospective Studies , Survival Rate
19.
Article En | MEDLINE | ID: mdl-34796237

The PhysioNet/Computing in Cardiology Challenge 2018 focused on the use of various physiological signals (EEG, EOG, EMG, ECG, SaO2) collected during polysomnographic sleep studies to detect sources of arousal (non-apnea) during sleep. A total of 1,983 polysomnographic recordings were made available to the entrants. The arousal labels for 994 of the recordings were made available in a public training set while 989 labels were retained in a hidden test set. Challengers were asked to develop an algorithm that could label the presence of arousals within the hidden test set. The performance metric used to assess entrants was the area under the precision-recall curve. A total of twenty-two independent teams entered the Challenge, deploying a variety of methods from generalized linear models to deep neural networks.

20.
Shock ; 48(4): 436-440, 2017 10.
Article En | MEDLINE | ID: mdl-28328711

PURPOSE: Atrial fibrillation with rapid ventricular response (RVR) is common during critical illness. In this study, we explore the comparative effectiveness of three commonly used drugs (metoprolol, diltiazem, and amiodarone) in the management of atrial fibrillation with RVR in the intensive care unit (ICU). METHODS: Data pertaining to the first ICU admission were extracted from the Medical Information Mart for Intensive Care III database. Patients who received one of the above pharmacologic agents while their heart rate was > 110 bpm and had atrial fibrillation documented in the clinical chart were included. Propensity score weighting using a generalized boosted model was used to compare medication failure rates (second agent prior to termination of RVR). Secondary outcomes included time to control, control within 4 h, and mortality. RESULTS: One thousand six hundred forty-six patients were included: 736 received metoprolol, 292 received diltiazem, and 618 received amiodarone. Compared with those who received metoprolol, failure rates were higher amongst those who received amiodarone (OR 1.39, 95% CI 1.03-1.87, P = 0.03) and there was a trend towards increased failure rates in patients who received diltiazem (OR 1.35, CI 0.89-2.07, P = 0.16). Amongst patients who received a single agent, patients who received diltiazem were less likely to be controlled at 4-h than those who received metoprolol (OR 0.64, CI 0.43-097, P = 0.03). Initial agent was not associated with in-hospital mortality. CONCLUSIONS: In this study, metoprolol was the most commonly used agent for atrial fibrillation with RVR. Metoprolol had a lower failure rate than amiodarone and was superior to diltiazem in achieving rate control at 4 h.


Amiodarone/administration & dosage , Atrial Fibrillation , Critical Care , Databases, Factual , Diltiazem/administration & dosage , Electronic Health Records , Metoprolol/administration & dosage , Aged , Aged, 80 and over , Atrial Fibrillation/drug therapy , Atrial Fibrillation/mortality , Disease-Free Survival , Female , Humans , Male , Middle Aged , Survival Rate
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