In Intensive Care Units (ICU), the abundance of multivariate time series
presents an opportunity for machine learning (ML) to enhance patient
phenotyping. In contrast to previous research focused on electronic health
records (EHR), here we propose an ML approach for phenotyping using routinely
collected physiological time series data. Our new algorithm integrates Long
Short-Term Memory (LSTM) networks with collaborative filtering concepts to
identify common physiological states across patients. Tested on real-world ICU
clinical data for intracranial hypertension (IH) detection in patients with
brain injury, our method achieved an area under the curve (AUC) of 0.889 and
average precision (AP) of 0.725. Moreover, our algorithm outperforms
autoencoders in learning more structured latent representations of the
physiological signals. These findings highlight the promise of our methodology
for patient phenotyping, leveraging routinely collected multivariate time
series to improve clinical care practices.

在重症监护室（ICU）中，多元时间序列的丰富性为机器学习提供了改进患者表型刻画的机会。与以往主要关注电子健康记录（EHR）的研究不同，本文提出了一种使用常规收集的生理时间序列数据进行表型刻画的机器学习方法。我们的新算法将长短期记忆（LSTM）网络与协同过滤的概念相结合，识别出患者之间共同的生理状态。在实际世界的 ICU 临床数据中测试，我们的方法在脑损伤患者颅内高压（IH）检测方面取得了 0.889 的曲线下面积（AUC）和 0.725 的平均精度（AP）。此外，我们的算法在学习生理信号的结构化潜在表示方面优于自编码器。这些发现突显了我们方法在利用常规多元时间序列改善临床护理实践的患者表型刻画方面的巨大潜力。

常规收集的多变量 ICU 生理信号中的共同潜在表示的协作学习

Collaborative learning of common latent representations in routinely  collected multivariate ICU physiological signals

Objective: We investigate whether deep learning techniques for natural
language processing (NLP) can be used efficiently for patient phenotyping.
Patient phenotyping is a classification task for determining whether a patient
has a medical condition, and is a crucial part of secondary analysis of
healthcare data. We assess the performance of deep learning algorithms and
compare them with classical NLP approaches.
Materials and Methods: We compare convolutional neural networks (CNNs),
n-gram models, and approaches based on cTAKES that extract pre-defined medical
concepts from clinical notes and use them to predict patient phenotypes. The
performance is tested on 10 different phenotyping tasks using 1,610 discharge
summaries extracted from the MIMIC-III database.
Results: CNNs outperform other phenotyping algorithms in all 10 tasks. The
average F1-score of our model is 76 (PPV of 83, and sensitivity of 71) with our
model having an F1-score up to 37 points higher than alternative approaches. We
additionally assess the interpretability of our model by presenting a method
that extracts the most salient phrases for a particular prediction.
Conclusion: We show that NLP methods based on deep learning improve the
performance of patient phenotyping. Our CNN-based algorithm automatically
learns the phrases associated with each patient phenotype. As such, it reduces
the annotation complexity for clinical domain experts, who are normally
required to develop task-specific annotation rules and identify relevant
phrases. Our method performs well in terms of both performance and
interpretability, which indicates that deep learning is an effective approach
to patient phenotyping based on clinicians' notes.

本文研究了深度学习技术在自然语言处理中是否可以有效用于患者表型特征提取和预测，并与传统 NLP 方法进行比较。结果表明，卷积神经网络是一种性能优良且易解释的深度学习方法，可以有效提高患者表型预测的性能，降低注释复杂度，并自动学习与每个患者表型相关的短语。