Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning
Background: Elevated nocturnal blood pressure (BP) is a risk factor for cardiovascular disease (CVD) and mortality. Cuffless BP assessment aided by machine learning could be a desirable alternative to traditional cuff-based methods for monitoring BP during sleep. We describe a machine-learning-based...
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MDPI AG
2023-09-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/18/7931 |
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| author | Gizem Yilmaz Xingyu Lyu Ju Lynn Ong Lieng Hsi Ling Thomas Penzel B. T. Thomas Yeo Michael W. L. Chee |
| author_facet | Gizem Yilmaz Xingyu Lyu Ju Lynn Ong Lieng Hsi Ling Thomas Penzel B. T. Thomas Yeo Michael W. L. Chee |
| author_sort | Gizem Yilmaz |
| collection | DOAJ |
| description | Background: Elevated nocturnal blood pressure (BP) is a risk factor for cardiovascular disease (CVD) and mortality. Cuffless BP assessment aided by machine learning could be a desirable alternative to traditional cuff-based methods for monitoring BP during sleep. We describe a machine-learning-based algorithm for predicting nocturnal BP using single-channel fingertip plethysmography (PPG) in healthy adults. Methods: Sixty-eight healthy adults with no apparent sleep or CVD (53% male), with a median (IQR) age of 29 (23–46 years), underwent overnight polysomnography (PSG) with fingertip PPG and ambulatory blood pressure monitoring (ABPM). Features based on pulse morphology were extracted from the PPG waveforms. Random forest models were used to predict night-time systolic blood pressure (SBP) and diastolic blood pressure (DBP). Results: Our model achieved the highest out-of-sample performance with a window length of 7 s across window lengths explored (60 s, 30 s, 15 s, 7 s, and 3 s). The mean absolute error (MAE ± STD) was 5.72 ± 4.51 mmHg for SBP and 4.52 ± 3.60 mmHg for DBP. Similarly, the root mean square error (RMSE ± STD) was 6.47 ± 1.88 mmHg for SBP and 4.62 ± 1.17 mmHg for DBP. The mean correlation coefficient between measured and predicted values was 0.87 for SBP and 0.86 for DBP. Based on Shapley additive explanation (SHAP) values, the most important PPG waveform feature was the stiffness index, a marker that reflects the change in arterial stiffness. Conclusion: Our results highlight the potential of machine learning-based nocturnal BP prediction using single-channel fingertip PPG in healthy adults. The accuracy of the predictions demonstrated that our cuffless method was able to capture the dynamic and complex relationship between PPG waveform characteristics and BP during sleep, which may provide a scalable, convenient, economical, and non-invasive means to continuously monitor blood pressure. |
| first_indexed | 2024-03-10T22:01:20Z |
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| id | doaj.art-546e020a0ab544d0a1c3dae1e526ab6f |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T22:01:20Z |
| publishDate | 2023-09-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-546e020a0ab544d0a1c3dae1e526ab6f2023-11-19T12:56:15ZengMDPI AGSensors1424-82202023-09-012318793110.3390/s23187931Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine LearningGizem Yilmaz0Xingyu Lyu1Ju Lynn Ong2Lieng Hsi Ling3Thomas Penzel4B. T. Thomas Yeo5Michael W. L. Chee6Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, SingaporeCentre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, SingaporeCentre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, SingaporeDepartment of Cardiology, National University Heart Centre Singapore, Singapore 119074, SingaporeInterdisciplinary Center of Sleep Medicine, Charité—Universitätsmedizin Berlin, 10117 Berlin, GermanyCentre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, SingaporeCentre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, SingaporeBackground: Elevated nocturnal blood pressure (BP) is a risk factor for cardiovascular disease (CVD) and mortality. Cuffless BP assessment aided by machine learning could be a desirable alternative to traditional cuff-based methods for monitoring BP during sleep. We describe a machine-learning-based algorithm for predicting nocturnal BP using single-channel fingertip plethysmography (PPG) in healthy adults. Methods: Sixty-eight healthy adults with no apparent sleep or CVD (53% male), with a median (IQR) age of 29 (23–46 years), underwent overnight polysomnography (PSG) with fingertip PPG and ambulatory blood pressure monitoring (ABPM). Features based on pulse morphology were extracted from the PPG waveforms. Random forest models were used to predict night-time systolic blood pressure (SBP) and diastolic blood pressure (DBP). Results: Our model achieved the highest out-of-sample performance with a window length of 7 s across window lengths explored (60 s, 30 s, 15 s, 7 s, and 3 s). The mean absolute error (MAE ± STD) was 5.72 ± 4.51 mmHg for SBP and 4.52 ± 3.60 mmHg for DBP. Similarly, the root mean square error (RMSE ± STD) was 6.47 ± 1.88 mmHg for SBP and 4.62 ± 1.17 mmHg for DBP. The mean correlation coefficient between measured and predicted values was 0.87 for SBP and 0.86 for DBP. Based on Shapley additive explanation (SHAP) values, the most important PPG waveform feature was the stiffness index, a marker that reflects the change in arterial stiffness. Conclusion: Our results highlight the potential of machine learning-based nocturnal BP prediction using single-channel fingertip PPG in healthy adults. The accuracy of the predictions demonstrated that our cuffless method was able to capture the dynamic and complex relationship between PPG waveform characteristics and BP during sleep, which may provide a scalable, convenient, economical, and non-invasive means to continuously monitor blood pressure.https://www.mdpi.com/1424-8220/23/18/7931nocturnal blood pressurephotoplethysmographycuffless blood pressure measurementblood pressure estimationcardiovascular healthsleep |
| spellingShingle | Gizem Yilmaz Xingyu Lyu Ju Lynn Ong Lieng Hsi Ling Thomas Penzel B. T. Thomas Yeo Michael W. L. Chee Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning Sensors nocturnal blood pressure photoplethysmography cuffless blood pressure measurement blood pressure estimation cardiovascular health sleep |
| title | Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning |
| title_full | Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning |
| title_fullStr | Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning |
| title_full_unstemmed | Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning |
| title_short | Nocturnal Blood Pressure Estimation from Sleep Plethysmography Using Machine Learning |
| title_sort | nocturnal blood pressure estimation from sleep plethysmography using machine learning |
| topic | nocturnal blood pressure photoplethysmography cuffless blood pressure measurement blood pressure estimation cardiovascular health sleep |
| url | https://www.mdpi.com/1424-8220/23/18/7931 |
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