Suitability of Unobtrusive Bed Monitoring and Wrist-worn Heart Rate Monitor for Patient Monitoring

Unobtrusive bed monitoring devices have gained popularity in the area of voluntary sleep quality monitoring for wellness purposes. Most of these devices rely on the measurement of ballistocardiographic forces caused by the acceleration of blood when the heart pumps it to aorta, forces caused by respiration movements and other movements of the person being monitored. A thin film-type force sensor placed under the bed mattress, between the matrices or under the bed sheet is often used for measuring these forces. While proven to provide adequate reliability and accuracy for wellness monitoring of healthy people, unobtrusive bed monitoring solutions have not yet been widely deployed in hospital patient monitoring even though there would be much use for such technology e.g. in regular hospital wards where currently the amount of patient monitoring is very limited.

If proven operational in this application, bed monitoring technology would provide tremendous benefits in both clinical and home monitoring scenarios. Wrist worn pulse plethysmography (PPG) devices have increased their popularity as heart rate monitors, referred as optical heart rate monitors (OHR) for sports and wellness in recent years and their ability to measure average heart rate during movement and beat-to-beat heart rate while at rest accurately with healthy people has been shown.

The objective of the study is to collect ECG and movement data measured with a wearable ECG monitor and simultaneously record data with unobtrusive bed sensor and wrist worn PPG device. Data recorded with the bed and wrist sensors and vital parameters calculated from that or provided by the monitoring devices directly will be compared with the reference.

The purpose of the study is to gain knowledge about the feasibility of unobtrusive bed and wrist monitoring devices for patient monitoring. The collected data will directly provide information on the accuracy of the current algorithms of the monitors. Besides this evaluation, the collected data will be used in developing new algorithms for detection of cardiac problems.

The study includes collection of data from vascular patients referred to surgical operation in Tampere University Hospital. Data collection takes place at vascular surgical ward where one dedicated research bed is equipped with bed monitoring devices. Another group of subjects is formed by healthy volunteers.

Inclusion criteria

• Age>50
• Indication for operation: peripheral arterial bypass and/or endarterectomy, aortic surgery, carotid surgery
• Volunteering

Exclusion criteria

• Pacemaker
• Denial