Digital Tools for Telehealth
Design a remote-care medical device that assesses whether a patient with cardiac heart failure (CHF) or chronic kidney disease (CKD) is hypervolemic (retains fluid) and integrate this digital tool within the existing checkup workflow for telemedicine.
Problem:: When the heart or kidney is not working, the body accumulates excess fluids in the blood. Water imbalances is a key indicator of poor heart or kidney management.
Create a sensor-based tool to monitor changes in blood fluid level non-invasively and to detect weight gain
- to facilitate remote provider examination
- to help patients monitor in between doctor’s visit to record changes
- to passively record the change in fluid accumulation and weight gain
Chronic heart failure and chronic kidney disease are two of the most common chronic conditions. Aging of the population and prolongation of the lives of cardiac patients by modern therapeutic innovations has led to an increasing prevalence of heart failure. Similarly, the overall prevalence of chronic kidney disease (CKD) increased significantly between 1999 and 2004. CHF and CKD present a tremendous burden on the healthcare system. Over 5 million people in the US have been diagnosed with CHF, resulting in 11 million office visits and 287,000 CHF related deaths annually. Over 660,000 Americans have CKD with 468,000 individuals requiring dialysis, which can cost $72,000 annually. In addition to direct healthcare costs, societal costs of advanced CKD include absenteeism, presenteeism, and premature death.
Take special consideration of the limitations of each indicator. For example, weight gain may be a result of increased adiposity as opposed to fluid retention. Similarly, low urine volume/day may be a result of decreased fluid intake. As a result, the device will most likely necessitate the development of an algorithm that will incorporate multiple measurements and contextual factors.
There are many clinical indicators of hypervolemia. Possible measurements for detecting volume overload include:
- Elevated blood pressure  (measure of intravascular volume)
- Edema / Swelling of extremities (can often roughly estimate extravascular volume but is limited in value to assess intravascular volume, requires several liters of water to be retained)
- Abdominal distention / ascites
- Weight gain
- Increases in body size (ankle, waist, etc.)
- Jugular venous distension
- High urine specific gravity (in context of fluid intake)
- Low urine volume/day (as compared to fluid intake)
- Ultrasonic inferior vena cava diameter (often subject to patient and operator variability)
- Biomarkers: brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-pro BNP) (inappropriate measure for CKD patients)
- Patients don’t like to be reminded that they are sick, they want to live a high quality of life with their condition.
- Tracking and measuring—the quantified self—is what keeps them out of the hospital.
Key facts demonstrating the importance of fluid balance in common chronic conditions:
- 5 million patients in the US
- 11 million office visits annually for CHF
- 287,000 deaths annually, CHF related
- Most frequently characterized by hypervolemia, expansion of plasma volume
- Goal for these patients according to American College of Cardiology/AHA guidelines is euvolemia
- Hospitals will not be reimbursed for patients readmitted in CHF within 30 days of discharge. Monitoring during this high-risk period can get patients to an outpatient appointment faster rather than the ER
Renal Failure (Chronic Kidney Disease, CKD)
- CKD substantially increases the risk of mortality and use of specialized health care
- Fluid overload often presents in patients with moderate to late stages of CKD
- Diabetes and hypertension are the primary causes of CKD
- Fluid overload has been associated with decline in renal function in non-dialysis dependent CKD patients
- 500,000 patients in US have end-stage renal disease (ESRD)
- Patients are less able to respond to intake of sodium and more prone to fluid overload
- Patients with CKD are at risk for cardiovascular disease, hyperkalemia, metabolic acidosis, MBDs, anemia
- Annual medical costs per patient with stages 4 to 5 CKD (not requiring dialysis) vary widely in evaluations of Medicare and private insurer spending, from roughly $7,000 to $65,000.
- There are significant indirect costs of advanced CKD associated with absenteeism, presenteeism, and premature death
- Blood Volume Determination, A Nuclear Medicine Test in Evolution, Margouleff, Donald MD, FACP