Virtual hospital implementation using a worn health monitor

Other Parts Discussed in Post: AFE4400

Guest blogger, Jess Goodman M.D., is the current President of VitalSines Inc., a company which manufactures health monitoring systems. Dr. Goodman is a physician with 30+ years of experience and currently serves on the University of Toronto Teaching Staff.

Congestive Heart Failure (CHF) and Chronic Obstructive Pulmonary Disease (COPD) are chronic illnesses that require careful monitoring to avoid need for hospitalization.  Hospitalization can be difficult for the patient and the patient’s family as well as being expensive for the health care system.

A report from the Pittsburgh Regional Health Initiative provides helpful information. Readmission rates for CHF and COPD are very high. Close to 26 percent of patients with CHF were readmitted within 30 days, and 55 percent were readmitted within one year. 23 percent of patients with COPD were readmitted within 30 days and 50 percent were readmitted within one year. Admissions costs were on average $15,196 for COPD and  $18,266 for CHF.  In the United States, $20 billion per year is spent on hospital treatment for CHF alone.

Research has shown that up to six out of ten readmissions for CHF and COPD are preventable. This is only one example of how a wrist-worn health monitor could help provide information to a clinical team with mobile capabilities that could help avert these re-admissions.

In my last post, I noted how the AFE4400 Oximeter SoC allows high quality acquisition of the arterial pulse signal at the wrist in ways not previously possible. Using the AFE4400 it is possible to monitor human physiology in new and effective ways.

Use of advanced technology to signal health care providers when health status is changing will allow prompt and effective intervention, avoiding hospital readmission. “Virtual hospital” wards are being set up in many regions to reduce readmissions to hospital. Virtual wards will reduce hospital readmissions by providing close monitoring and clinical services for patients with CHF and COPD recently discharged from hospital.

CHF and COPD both result in shortness of breath, fatigue and decreased ability to participate in activity. By using an oximeter to follow blood oxygen concentration, heart rate, respiratory rate and blood pressure changes, CHF and COPD can be characterized. When an oximeter is combined with a motion sensor, able to track activity and room-to-room travel, it becomes possible to recognize subtle features that indicate deterioration in status even before a patient has noticed any change in symptoms.

In designing a home health monitoring system that could use data aggregated by an oximeter, it is important that it be simple to install and use, be able to monitor health 24 hours a day, easily send information to a health care team, avoid overloading already busy health care practitioners with mountains of data and recognize that emergency notification should be managed by 911 services.

Let’s consider John, a patient with CHF, returning home after a hospital admission. He will be monitored using a Virtual Hospital approach.  Before John leaves hospital he is fitted with a health-monitoring wristwatch called the BioWatch. John is shown how to adjust the BioWatch strap so that it is well positioned but comfortable. John is shown how, once a day, he will take the BioWatch he is wearing and exchange it for an identical BioWatch on a recharger stand kept in his home. The recharger stand is equipped with WiFI and able to communicate with the hospital’s Internet server. John is informed that he can wear the BioWatch when he takes a shower, when he sleeps, when he goes to work and when he goes bowling.

John has a heart condition called Idiopathic Cardiomyopathy that results in weakening of the heart muscle. John is feeling much better than when he first went into hospital. In hospital he was started on a diuretic medication that acts as a ‘water pill’. He is able to walk and engage in his usual activities without any shortness of breath or fatigue.

John is on medications twice daily and his BioWatch buzzes and displays a message on its LCD screen to prompt John to take his medications. After he has taken his medications John simply taps the watch’s screen to send his Virtual Hospital team a confirmation message.

John’s Virtual Hospital team visited John at home shortly after he first returned from hospital. They entered a simple floor plan of his home, including stairs, into the hospital computer’s memory. John’s BioWatch has a compass and motion sensor able to track John’s room-to-room movements.

Once a day the hospital computer server sends a summary report on John’s health to his Virtual Hospital team. The team nurse reviews the one page report noting that heart rate, respiratory rate, blood pressure, blood oxygen saturation and activity levels are all at levels normal for John.

Three weeks after John left hospital, the Virtual Hospital nurse reviewing his daily report noticed that after climbing stairs his blood oxygen level dropped slightly and his heart rate was elevated more than usual. She called John and found out that he was feeling well, without any symptoms of shortness of breath or fatigue. She asked John to call if he felt unwell. Over the next week, the Virtual Hospital team noticed that John’s walking speed was slowing down and that he was spending more time in bed. He still reported feeling well, but the Virtual Hospital team arranged a home visit to make sure.

The visiting nurse practitioner examined John and noticed that he had slightly increased leg swelling and faint crackles were heard when she listened to his lungs. She performed an ECG recording that showed no serious heart issues. She called John’s pharmacy and ordered a slight increase in the dosage of his diuretic medication and informed John that she would call the next day to see how he was doing. 

The next day John reported that he was feeling well and his Biowatch report showed increased walking speed, less time spent in bed and less of a drop in blood oxygen with stair climbing.

The BioWatch is in fact being prototyped and will be available in a few months for clinical trials. The AFE4400 Oximeter SoC allows the BioWatch to acquire high quality oximetry signals from the wrist and creates a more effective Virtual Hospital model.

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