There is a pressing need to reduce the hospitalization rate of heart failure patients to limit rising health care costs and improve outcomes. Tracking physiologic changes to detect early deterioration in the home has the potential to reduce hospitalization rates through early intervention. However, classical approaches to in home monitoring have had limited success, with patient adherence cited as a major barrier.
To contain costs, the Centers for Medicare and Medicaid Services is both penalizing hospitals with excess readmission’s and moving to Bundled Payments for Care Improvement. Despite increasing penalties, readmission rates remain high for HF, with over 20% of patients readmitted within 30 days and up to 50% by 6 months. To successfully reduce readmission, early detection of deterioration and subsequent intervention is required.
Since patient awareness of symptomatology often lags behind deterioration, successfully tracking physiologic changes in the home is a critical component of an early intervention strategy.In contrast to these studies, the CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial demonstrated a 37% reduction in class III HF hospitalizations.
Where pulmonary artery pressures were measure daily through an implantable device (CardioMEMS) incorporating a patient-initiate data transfer using a bed-based system. In comparison with prior studies that did not show a reduction in hospitalization, only 1.5% of the treatment group was noncompliant. In the Champion Trial, the high level of adherence was due to the patient selection criteria, a preprocedure monitoring agreement, and the use of a nurse telephone intervention system.
Consistent monitoring of BP
HF occurs when the heart muscle is weaken and unable to maintain sufficient blood flow to meet the body’s needs. Consistent monitoring of BP is critical throughout the entire management and treatment of HF; so as optimal BP control is a primary goal for HF. As HF is characterize by poor cardiac performance, so cardiac output (CO) is an important component in diagnosis and management of HF.
The toilet seat based estimates of blood pressure and peripheral blood oxygenation; hence were compare to a hospital-grade vital signs monitor for 18 subjects over an 8-week period. The estimated stroke volume was validated on 38 normative subjects and 111 subjects undergoing a standard echocardiogram; which at a hospital clinic for any underlying condition; also including heart failure.
This work demonstrates that a toilet seat based monitoring system is capable of accurately capturing the following clinically relevant parameters like BP, SV, and blood oxygenation. The single-lead ECG measure from the seat has previously correlate to the 12-lead ECG; it also validated against standard lead II for HR, heart rate variability, QRS duration, and the correct QT interval and will not be discuss herein.
The propose cardiovascular monitoring system installs directly on a standard toilet; which is battery powered, wireless, waterproof, and requires no additional connections or user interaction. This monitoring system unobtrusively captures cardiovascular data automatically whenever the user sits on the toilet. Requiring no direct user actions for measurement; also patient adherence is enhance.
The seat incorporates a single-lead ECG for measuring the electrical activity of the heart; also as a reference for ensemble averaging a ballistocardiogram (BCG); which is used for measuring the mechanical forces associated with the cardiac cycle; also a photoplethysmogram (PPG) for measuring SpO2 and pulse transit time (PTT).
Benefits of this System
Main benefits of the proposed system is the ability to use a combination of the ECG, BCG, and PPG to extract meaningful parameters such as BP. Literature shows that it is possible to estimate BP from pulse wave velocity (PWV); which is the speed at which the pressure wave propagates through the arterial system. This work demonstrates that a toilet seat based cardiovascular monitoring system; hence can robustly measure systolic and diastolic BP, SV, and SpO2 compared to their respective clinical gold standards.
Results show that SV can be estimate absolutely with an accuracy comparable to the echocardiogram; which is the most commonly use method for measuring SV. Both systolic and diastolic BP can be measure in a normative population over a period of 8 weeks; using the ECG, BCG, and PPG with a per-subject calibration within the AAMI standards.
The seat is capable of measuring a subject’s SpO2 using a reflectance mode pulse oximeter position; hence to make contact with the upper thigh; with a single-point calibration for each subject. The single-lead ECG, HR, HRV, QRS duration, and corrected QT interval has previously validated. The toilet seat–based cardiovascular monitoring system has the potential fill a gap in patient; hence by monitoring and capturing trend data that has previously unattainable.
This system has the potential to address many of the challenges with in-home monitoring in a form factor that integrates into the daily routine of patients; hence bypassing barriers to adherence and providing a comprehensive and accurate set of clinically relevant measurements. If successful, this strategy has the potential to reduce the burden of HF; also cardiovascular disease on the health care industry as well as improve the quality of life for patients.