目的:早产儿呼吸暂停是新生儿重症监护病房中最常见的诊断之一。呼吸暂停可以归类为中心,阻塞的或混合的。根据目前的国际标准,胸部阻抗(CI)的最小波动或无波动提示中枢神经性呼吸暂停(CA).然而,自动检测降低CI波动会导致大量的中枢呼吸暂停疑似事件(CASE),大多数是假警报。我们的目标是通过使用机器学习来优化CASE之间的CA检测来提高CA的自动检测。
方法:使用优化的算法进行自动检测,所有CASE均在10例发生迟发性脓毒症的早产儿和10例年龄匹配的对照患者中检测到.CASE由两名临床专家检查,并在两轮注释中将其注释为CA或拒绝。从心电图中总共提取了47个特征,CI和氧饱和度信号考虑四个30s长的移动窗口,从每个病例开始前30秒到15秒后,使用5s的移动步长。连续,基于带弹性网罚的Logistic回归,开发了新的CA检测模型,随机森林和支持向量机。考虑到接受者操作特征曲线下的平均面积(AUROC),使用留一患者和10倍交叉验证来评估性能。
结果:当包含从所有四个时间窗口提取的特征时,基于具有弹性净惩罚的逻辑回归的CA检测模型返回的平均AUROC最高,两者均使用留一患者和10倍交叉验证(平均AUROC分别为0.88和0.90).发现从CI派生的特征的特征相关性最高。平均接收器工作特性曲线中的假阳性率阈值等于0.3,导致所有CA的正确检测百分比较高(78.2%),其次是心动过缓(93.4%)和CA,其次是心动过缓和去饱和(95.2%)。这对早产儿的健康更为关键。
结论:基于机器学习的模型可以改善CA检测,减少误报。
OBJECTIVE: Apnea of prematurity is one of the most common diagnosis in neonatal intensive care units. Apneas can be classified as central, obstructive or mixed. According to the current international standards, minimal fluctuations or absence of fluctuations in the chest impedance (CI) suggest a central apnea (CA). However, automatic detection of reduced CI fluctuations leads to a high number of central apnea-suspected events (CASEs), the majority being false alarms. We aim to improve automatic detection of CAs by using machine learning to optimize detection of CAs among CASEs.
METHODS: Using an optimized algorithm for automated detection, all CASEs were detected in a population of 10 premature infants developing late-onset sepsis and 10 age-matched control patients. CASEs were inspected by two clinical experts and annotated as CAs or rejections in two rounds of annotations. A total of 47 features were extracted from the ECG, CI and oxygen saturation signals considering four 30 s-long moving windows, from 30 s before to 15 s after the onset of each CASE, using a moving step size of 5 s. Consecutively, new CA detection models were developed based on logistic regression with elastic net penalty, random forest and support vector machines. Performance was evaluated using both leave-one-patient-out and 10-fold cross-validation considering the mean area under the receiver-operating-characteristic curve (AUROC).
RESULTS: The CA detection model based on logistic regression with elastic net penalty returned the highest mean AUROC when features extracted from all four time windows were included, both using leave-one-patient-out and 10-fold cross-validation (mean AUROC of 0.88 and 0.90, respectively). Feature relevance was found to be the highest for features derived from the CI. A threshold for the false positive rate in the mean receiver-operating-characteristic curve equal to 0.3 led to a high percentage of correct detections for all CAs (78.2%) and even higher for CAs followed by a bradycardia (93.4%) and CAs followed by both a bradycardia and a desaturation (95.2%), which are more critical for the well-being of premature infants.
CONCLUSIONS: Models based on machine learning can lead to improved CA detection with fewer false alarms.