Remote Vital Signs Monitoring in Neonatal Intensive Care Unit Using a Digital Camera

Authors: Fatema-Tuz-Zohra Khanam, Ali Al-Naji, Asanka G. Perera, Kim Gibson, Javaan Chahl

Abstract:

Conventional contact-based vital signs monitoring sensors such as pulse oximeters or electrocardiogram (ECG) may cause discomfort, skin damage, and infections, particularly in neonates with fragile, sensitive skin. Therefore, remote monitoring of the vital sign is desired in both clinical and non-clinical settings to overcome these issues. Camera-based vital signs monitoring is a recent technology for these applications with many positive attributes. However, there are still limited camera-based studies on neonates in a clinical setting. In this study, the heart rate (HR) and respiratory rate (RR) of eight infants at the Neonatal Intensive Care Unit (NICU) in Flinders Medical Centre were remotely monitored using a digital camera applying color and motion-based computational methods. The region-of-interest (ROI) was efficiently selected by incorporating an image decomposition method. Furthermore, spatial averaging, spectral analysis, band-pass filtering, and peak detection were also used to extract both HR and RR. The experimental results were validated with the ground truth data obtained from an ECG monitor and showed a strong correlation using the Pearson correlation coefficient (PCC) 0.9794 and 0.9412 for HR and RR, respectively. The root mean square errors (RMSE) between camera-based data and ECG data for HR and RR were 2.84 beats/min and 2.91 breaths/min, respectively. A Bland Altman analysis of the data also showed a close correlation between both data sets with a mean bias of 0.60 beats/min and 1 breath/min, and the lower and upper limit of agreement -4.9 to + 6.1 beats/min and -4.4 to +6.4 breaths/min for both HR and RR, respectively. Therefore, video camera imaging may replace conventional contact-based monitoring in NICU and has potential applications in other contexts such as home health monitoring.

Keywords: Neonates, NICU, digital camera, heart rate, respiratory rate, image decomposition.

References:

[1] X. Chen, J. Cheng, R. Song, Y. Liu, R. Ward, and Z. J. Wang, "Video-Based Heart Rate Measurement: Recent Advances and Future Prospects," IEEE Transactions on Instrumentation and Measurement, 2018.
[2] F.-T.-Z. Khanam, A. Al-Naji, and J. Chahl, "Remote Monitoring of Vital Signs in Diverse Non-Clinical and Clinical Scenarios Using Computer Vision Systems: A Review," Applied Sciences, vol. 9, no. 20, p. 4474, 2019.
[3] F.-T.-Z. Khanam et al., "Noncontact Sensing of Contagion," Journal of Imaging, vol. 7, no. 2, p. 28, 2021.
[4] F. Zhao, M. Li, Y. Qian, and J. Z. Tsien, "Remote measurements of heart and respiration rates for telemedicine," PloS one, vol. 8, no. 10, p. e71384, 2013.
[5] M. M. Baharestani, "An overview of neonatal and pediatric wound care knowledge and considerations," Ostomy/wound management, vol. 53, no. 6, p. 34, 2007.
[6] J. M. Kuller, "Skin breakdown: risk factors, prevention, and treatment," Newborn and Infant Nursing Reviews, vol. 1, no. 1, pp. 35-42, 2001.
[7] R. G. Pineda et al., "Alterations in brain structure and neurodevelopmental outcome in preterm infants hospitalized in different neonatal intensive care unit environments," The Journal of pediatrics, vol. 164, no. 1, pp. 52-60. e2, 2014.
[8] W. Lv, W. He, X. Lin, and J. Miao, "Non-Contact Monitoring of Human Vital Signs Using FMCW Millimeter Wave Radar in the 120 GHz Band," Sensors, vol. 21, no. 8, p. 2732, 2021.
[9] M. Mercuri, Y.-H. Liu, I. Lorato, T. Torfs, A. Bourdoux, and C. Van Hoof, "Frequency-tracking CW Doppler radar solving small-angle approximation and null point issues in non-contact vital signs monitoring," IEEE transactions on biomedical circuits and systems, vol. 11, no. 3, pp. 671-680, 2017.
[10] A. K. Abbas, K. Heiman, T. Orlikowsky, and S. Leonhardt, "Non-contact respiratory monitoring based on real-time IR-thermography," in World Congress on Medical Physics and Biomedical Engineering, September 7-12, 2009, Munich, Germany, 2009: Springer, pp. 1306-1309.
[11] S. Bennett, T. N. El Harake, R. Goubran, and F. Knoefel, "Adaptive Eulerian Video Processing of Thermal Video: An Experimental Analysis," IEEE Transactions on Instrumentation and Measurement, vol. 66, no. 10, pp. 2516-2524, 2017.
[12] A. Al-Naji and J. Chahl, "Contactless cardiac activity detection based on head motion magnification," International Journal of Image and Graphics, vol. 17, no. 01, p. 1750001, 2017.
[13] J. Cheng, X. Chen, L. Xu, and Z. J. Wang, "Illumination variation-resistant video-based heart rate measurement using joint blind source separation and ensemble empirical mode decomposition," IEEE journal of biomedical and health informatics, vol. 21, no. 5, pp. 1422-1433, 2017.
[14] F.-T.-Z. Khanam, A. G. Perera, A. Al-Naji, K. Gibson, and J. Chahl, "Non-contact automatic vital signs monitoring of infants in a neonatal intensive care unit based on neural networks," Journal of Imaging, vol. 7, no. 8, p. 122, 2021.
[15] A. Al-Naji, K. Gibson, S.-H. Lee, and J. Chahl, "Monitoring of cardiorespiratory signal: Principles of remote measurements and review of methods," IEEE Access, vol. 5, pp. 15776-15790, 2017.
[16] G. Balakrishnan, F. Durand, and J. Guttag, "Detecting pulse from head motions in video," in Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2013, pp. 3430-3437.
[17] A. Al-Naji and J. Chahl, "Detection of cardiopulmonary activity and related abnormal events using Microsoft Kinect sensor," Sensors, vol. 18, no. 3, p. 920, 2018.
[18] J.-P. Lomaliza and H. Park, "Detecting Pulse from Head Motions Using Smartphone Camera," in International Conference on Advanced Engineering Theory and Applications, 2016: Springer, pp. 243-251.
[19] A. Al-Naji and J. Chahl, "Remote respiratory monitoring system based on developing motion magnification technique," Biomedical Signal Processing and Control, vol. 29, pp. 1-10, 2016.
[20] W. Verkruysse, L. O. Svaasand, and J. S. Nelson, "Remote plethysmographic imaging using ambient light," Optics express, vol. 16, no. 26, pp. 21434-21445, 2008.
[21] M.-Z. Poh, D. J. McDuff, and R. W. Picard, "Non-contact, automated cardiac pulse measurements using video imaging and blind source separation," Optics express, vol. 18, no. 10, pp. 10762-10774, 2010.
[22] W. Wang, A. C. den Brinker, S. Stuijk, and G. de Haan, "Algorithmic principles of remote PPG," IEEE Transactions on Biomedical Engineering, vol. 64, no. 7, pp. 1479-1491, 2017.
[23] A. Al-Naji and J. Chahl, "Remote Optical Cardiopulmonary Signal Extraction with Noise Artifact Removal, Multiple Subject Detection & Long-Distance," IEEE Access, vol. 6, pp. 11573-11595, 2018.
[24] F. Bousefsaf, C. Maaoui, and A. Pruski, "Continuous wavelet filtering on webcam photoplethysmographic signals to remotely assess the instantaneous heart rate," Biomedical Signal Processing and Control, vol. 8, no. 6, pp. 568-574, 2013.
[25] L. Scalise, N. Bernacchia, I. Ercoli, and P. Marchionni, "Heart rate measurement in neonatal patients using a webcamera," in 2012 IEEE International Symposium on Medical Measurements and Applications Proceedings, 2012: IEEE, pp. 1-4.
[26] L. A. Aarts et al., "Non-contact heart rate monitoring utilizing camera photoplethysmography in the neonatal intensive care unit—A pilot study," Early human development, vol. 89, no. 12, pp. 943-948, 2013.
[27] J. H. Klaessens, M. van den Born, A. van der Veen, J. Sikkens-van de Kraats, F. A. van den Dungen, and R. M. Verdaasdonk, "Development of a baby friendly non-contact method for measuring vital signs: first results of clinical measurements in an open incubator at a neonatal intensive care unit," in Advanced Biomedical and Clinical Diagnostic Systems XII, 2014, vol. 8935: International Society for Optics and Photonics, p. 89351P.
[28] K. Gibson et al., "Non-contact heart and respiratory rate monitoring of preterm infants based on a computer vision system: a method comparison study," Pediatric Research, p. 1, 2019.
[29] M. Paul et al., "Non-contact sensing of neonatal pulse rate using camera-based imaging: a clinical feasibility study," Physiological Measurement, vol. 41, no. 2, p. 024001, 2020.
[30] J.-C. Cobos-Torres, M. Abderrahim, and J. Martínez-Orgado, "Non-Contact, Simple Neonatal Monitoring by Photoplethysmography," Sensors, vol. 18, no. 12, p. 4362, 2018.
[31] Q. Chen et al., "Camera-based heart rate estimation for hospitalized newborns in the presence of motion artifacts," BioMedical Engineering OnLine, vol. 20, no. 1, pp. 1-16, 2021.
[32] L. K. Mestha, S. Kyal, B. Xu, L. E. Lewis, and V. Kumar, "Towards continuous monitoring of pulse rate in neonatal intensive care unit with a webcam," in 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2014: IEEE, pp. 3817-3820.
[33] M. Villarroel et al., "Continuous non-contact vital sign monitoring in neonatal intensive care unit," Healthcare technology letters, vol. 1, no. 3, pp. 87-91, 2014.
[34] E. C. Eichenwald, "Apnea of prematurity," Pediatrics, vol. 137, no. 1, 2016.