Exploring Early Pre-Symptomatic Detection of Influenza Using Continuous Monitoring of Advanced Physiological Parameters during a Randomized Controlled Trial.

Early detection of influenza may improve responses against outbreaks. This study was part of a clinical study assessing the efficacy of a novel influenza vaccine, aiming to discover distinct, highly predictive patterns of pre-symptomatic illness based on changes in advanced physiological parameters using a novel wearable sensor. Participants were frequently monitored 24 h before and for nine days after the influenza challenge. Viral load was measured daily, and self-reported symptoms were collected twice a day. The Random Forest classifier model was used to classify the participants based on changes in the measured parameters. A total of 116 participants with ~3,400,000 data points were included. Changes in parameters were detected at an early stage of the disease, before the development of symptomatic illness. Heart rate, blood pressure, cardiac output, and systemic vascular resistance showed the greatest changes in the third post-exposure day, correlating with viral load. Applying the classifier model identified participants as flu-positive or negative with an accuracy of 0.81 ± 0.05 two days before major symptoms appeared. Cardiac index and diastolic blood pressure were the leading predicting factors when using data from the first and second day. This study suggests that frequent remote monitoring of advanced physiological parameters may provide early pre-symptomatic detection of flu.

Continuous Remote Patient Monitoring Shows Early Cardiovascular Changes in COVID-19 Patients.

COVID-19 exerts deleterious cardiopulmonary effects, leading to a worse prognosis in the most affected. This retrospective multi-center observational cohort study aimed to analyze the trajectories of key vitals amongst hospitalized COVID-19 patients using a chest-patch wearable providing continuous remote patient monitoring of numerous vital signs. The study was conducted in five COVID-19 isolation units. A total of 492 COVID-19 patients were included in the final analysis. Physiological parameters were measured every 15 min. More than 3 million measurements were collected including heart rate, systolic and diastolic blood pressure, cardiac output, cardiac index, systemic vascular resistance, respiratory rate, blood oxygen saturation, and body temperature. Cardiovascular deterioration appeared early after admission and in parallel with changes in the respiratory parameters, showing a significant difference in trajectories within sub-populations at high risk. Early detection of cardiovascular deterioration of COVID-19 patients is achievable when using frequent remote patient monitoring.

A Pilot Study of Blood Pressure Monitoring After Cardiac Surgery Using a Wearable, Non-invasive Sensor.

Background: Continuous blood pressure (BP) measurement in intensive care units is based on arterial line (AL) transducers, sometimes associated with clinical complications. Our objective was to evaluate continuous BP measurements obtained from a non-invasive, wireless photoplethysmography (PPG)-based device using two distinct configurations (wristwatch and chest-patch monitors) compared to an AL. Methods: In this prospective evaluation study, comparison of the PPG-based devices to the AL was conducted in 10 patients immediately following cardiac surgery. Pulse rate (PR), systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) were recorded using both the AL and the PPG-based devices simultaneously for an average of 432 ± 290 min starting immediately after cardiac surgery. Bland-Altman plots and Pearson's correlations were used to assess the accuracy and degree of agreement between techniques. Results: A total of ~4,000 data points were included in the final analysis. AL measurements for PR, SBP, DBP and MAP were significantly (p < 0.001) and strongly correlated with both the wristwatch (r = 0.99, r = 0.94, r = 0.93 and r = 0.96, respectively) and the chest-patch (r = 0.99, r = 0.95, r = 0.93 and r = 0.95, respectively) monitors. Both configurations showed a marginal bias of <1 mmHg for BP measurements and <1 beat/min for PR [95% limits of agreement -3,3 beat/min; BP measurements: (-6)-(-10), 6-10 mmHg] compared to AL measurements. Conclusion: The PPG-based devices offer a high level of accuracy for cardiac-related parameters compared to an AL in post-cardiac surgery patients. Such devices could provide advanced monitoring capabilities in a variety of clinical settings, including immediate post-operative and intensive care unit settings. Clinical Trial Registration:www.clinicaltrials.gov, NCT03603860.

Twenty-Four-Hour Ambulatory Blood Pressure Measurement Using a Novel Noninvasive, Cuffless, Wireless Device.

BACKGROUND: Ambulatory blood pressure monitoring (ABPM) using cuff-based devices is used for diagnosis and treatment of hypertension. Technical limitations, low compliance, and complex procedures limit their use. The aim of the present study was to test the accuracy of a new photoplethysmography-based, wearable device (Wrist-monitor) as compared with the standard cuff-based ABPM device. METHODS: Twenty-four-hour (24H) ABPM was performed in parallel for both devices on volunteers aged 18-65 years, while documenting their daily activities. Level of comfort and activity disturbance of both devices were recorded. Linear regression and Bland-Altman were used to evaluate the agreement between devices. Receiver operating characteristic (ROC) curve analysis was used to classify hypertension based on the average Wrist-monitor measurements as compared with a cuff-based ABPM device. RESULTS: The study included 28 subjects (18 men) mean age 41.5 ± 16.2 years. Bland-Altman analysis resulted in 24H bias of -1.1 mm Hg for both diastolic blood pressure (DBP) and systolic blood pressure (SBP). Mean daytime bias was -1.9 mm Hg for DBP and SBP, while nighttime bias was smaller (0.7 and 0.4 mm Hg for DBP and SBP, respectively). ROC curve analysis yielded a mean area under the curve (AUC) of 1 for SBP and 24H blood pressure measurements. AUCs of 0.994 and 0.955 were found for the daytime DBP and night DBP, respectively. 24H ABPM with the Wrist-monitor caused significantly less inconvenience compared with the cuff-based device (P < 0.001). CONCLUSIONS: The cuffless device provides comparable measurements to those obtained with the currently used cuff-based ABPM device, with significantly less inconvenience to the subject. CLINICAL TRIALS REGISTRATION: Trial Number NCT03810586.

Continuous Maternal Hemodynamics Monitoring at Delivery Using a Novel, Noninvasive, Wireless,PPG-Based Sensor.

OBJECTIVE: To evaluate continuous monitoring of maternal hemodynamics during labor and delivery utilizing an innovative, noninvasive, reflective photoplethysmography-based device. STUDY DESIGN: The Biobeat Monitoring Platform includes a wearable wristwatch monitor that automatically samples cardiac output (CO), blood pressure (BP), stroke volume (SV), systemic vascular resistance (SVR), heart rate (HR) every 5 s and uploads all data to a smartphone-based app and to a data cloud, enabling remote patient monitoring and analysis of data. Low-risk parturients at term, carrying singletons pregnancies, were recruited at early delivery prior to the active phase. Big data analysis of the collected data was performed using the Power BI analysis tool (Microsoft). Next, data were normalized to visual presentation using Excel Data Analysis and the regression tool. Average measurements were compared before and after rupture of membranes, epidural anesthesia, fetal delivery, and placental expulsion. RESULTS: Eighty-one parturients entered analysis. Epidural anesthesia was associated with a slight elevation in CO (5.5 vs. 5.6, L/min, 10 min before and after EA, p <0.05) attributed to a non-significant increase in both HR and SV. BP remained stable as of counter decrease in SVR (1361 vs. 1319 mmHg⋅min⋅mL-1, 10 min before and after EA, p <0.05). Fetal delivery was associated with a peak in CO after which it rapidly declined (6.0 vs. 7.2 vs. 6.1 L/min, 30 min before vs. point of delivery vs. after delivery, p <0.05). The mean BP remained stable throughout delivery with a slight increase at fetal delivery (92 vs. 95 vs. 92.1 mmHg, p <0.05), reflecting the increase in CO and decrease in SVR (1284 vs. 1112 vs. 1280 mmHg⋅min⋅mL-1,p <0.05)with delivery. Placental expulsion was associated with a second peak in CO and decrease in SVR. CONCLUSIONS: We presented a novel application of noninvasive hemodynamic maternal monitoring throughout labor and delivery for both research and clinical use.

Wireless, non-invasive, wearable device for continuous remote monitoring of hemodynamic parameters in a swine model of controlled hemorrhagic shock.

Accurate and continuous monitoring of critically ill patients is frequently achieved using invasive catheters, which is technically complex. Our purpose was to evaluate the validity and accuracy of a photoplethysmography (PPG)-based remote monitoring device compared to invasive methods of arterial line (AL) and Swan-Ganz (SG) catheters in a swine model of controlled hemorrhagic shock. Following a baseline phase, hemorrhagic shock was induced in 11 pigs by bleeding 35% of their blood volume, followed by a post-bleeding follow-up phase. Animals were monitored concomitantly by the PPG device, an AL and a SG catheter, for a median period of 447 min. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP, respectively), and cardiac output (CO) were recorded continuously. The complete data set consisted of 1312 paired observations. Correlations between the PPG-based technique and the invasive methods were significant (p < 0.001) during baseline, bleeding and follow-up phases for HR (r = 0.90-0.98), SBP (r = 0.90-0.94), DBP (r = 0.89-0.93), and CO (r = 0.76-0.90). Intraclass correlations for all phases combined were 0.96, 0.92, 0.93 and 0.87 for HR, SBP, DBP and CO, respectively. Correlations for changes in CO, SBP and DBP were significant (p < 0.001) and strong (r > 0.88), with concordance rates (determined by quadrant plots) of 86%, 66% and 68%, respectively. The novel PPG-based device was accurate and valid compared to existing invasive techniques and might be used for continuous monitoring in several clinical settings following further studies.

Comparing blood pressure measurements between a photoplethysmography-based and a standard cuff-based manometry device.

Repeated blood pressure (BP) measurements allow better control of hypertension. Current measurements rely on cuff-based devices. The aim of the present study was to compare BP measurements using a novel cuff-less photoplethysmography-based device to a standard sphygmomanometer device. Males and females were recruited from within the general population who arrived at a public BP screening station. One to two measurements were taken from each using a sphygmomanometer-based and the photoplethysmography-based devices. Devices were considered equal if the mean difference between paired measurements was below 5 mmHg and the Standard Deviation (SD) was no greater than 8 mmHg. Agreement and reliability analyses were also performed. 1057 subjects were included in the study analysis. There were no adverse events during the study. The mean (± SD) difference between paired measurements for all subjects was -0.1 ± 3.6 mmHg for the systolic and 0.0 ± 3.5 mmHg for the diastolic readings. We found 96.31% agreement in identifying hypertension and an Interclass Correlation Coefficient of 0.99 and 0.97 for systolic and diastolic measurements, respectively. The photoplethysmography-based device was found similar to the gold-standard sphygmomanometer-based device with high agreement and reliability levels. The device might enable a reliable, more convenient method for repeated BP monitoring.