“It has turned out that six out of seven patients with corona infection can be treated on an outpatient basis – so the hospitals can concentrate on the more serious cases”, recently the German Minister of Health, Jens Spahn, said.
About eighty percent of these outpatients will experience a mild course of the disease, many might even not be aware that they had the virus. But there is also a significant number of patients who will make a very unpleasant acquaintance with the virus. The transition from a mild to an acute live threatening situation can occur fast. A seemingly well doing patient can become within hours one these more serious cases that need to be hospitalised.
Pneumonia is one of the serious complications related to Covid-19. Recent reports seem to indicate that Covid-19 pneumonia shows unusual symptoms. In New York Times(4/20/20), emergency room doctor Richard Levitan, speaks about “silent hypoxia” — “silent because of its insidious, hard-to-detect nature”. Patients with such a kind of hypoxia often do not report any sensation of breathing problems, even though their chest X-rays already shows diffuse pneumonia, and their oxygen is below normal. These patients must be treated urgently in hospital, “otherwise they might go on to a second and deadlier phase of lung injury”.
An early and seemingly reliable warning sign that a patient is about to develop Covid-19 pneumonia, is his low saturation of blood oxygen. In hospital, blood oxygen is measured with a device called pulse oximeter. By providing the patients at home with pulse oximeters we can save the lives of many outpatients just by alerting them or their cohabitants early on the need of intensive treatment.
Richard Levitan says:
All patients who have been tested positive for the coronavirus should have pulse oximetry monitoring for two weeks, the period during which Covid pneumonia typically develops. All persons with cough, fatigue and fevers should also have pulse oximeter monitoring even if they have not had virus testing, or even if their swab test was negative, because those tests are only about 70 percent accurate.
Unfortunately, simple pulse oximeters for use at home are currently sold out.
Alternatively there are a number smart watches that have build-in pulse oximeter. At first sight it might seem exaggerated to use such a sophisticated technology for just measuring something as simple as blood oxidation.
But at a second glance, using the smart-watch in combination with a smart-phone has many attractive advantages.
- The smart watch can be worn twenty-four hours a day and thus the patient will be continuously monitored (with some breaks for recharging the device).
- On the watch itself we can implement algorithms that correlate blood oxidation with heart rate and thus make the predictions more robust against false alarms.
- Using continuously collected data allows a much better quality of prediction than one single measure taken every day. This also adds to the robustness against false alarms.
- Imagine for example, if a person living alone faints due to hypoxia, the smart phone could be programmed to issue an emergency call to a predefined phone number, e.g. a neighbor who can look after the patient, or the patient’s physician (calling the emergency automatically, is probably not such a good idea, because of false alarms).
- The data collected by the smart-watch is usually uploaded to a cloud. Making this data available to the physician, he can survey his Corona-patients on a daily basis without the need to visit or call. This data could be enriched by the patient reporting his subjective state of health.
- Provided that the patient and the physician agree to share the data from the cloud, we (the programmers) have a means to continuously improve our prediction algorithms on the basis of real empirical data.
- Last not least, the smart-watch will turn out to be a nice gadget used much more for leisure than for patient monitoring.
In this project we propose to realize a system composed of two parts. One part is implemented on the smart watch itself. The other part is implemented on the smart phone. The smart watch and the smart phone communicate as usual trough Bluetooth Low Energy (BLE)
On the smart watch itself we implement the algorithms that interpret the readings from the SpO2 sensors, compare them to previous readings, do the same with heart rate readings and finally decide whether hypoxia alarm should be given.
Furthermore, the smart watch must have the means of self testing. That is, the smart watch must be able to monitor the status of its battery and the correct functioning of its SpO2 sensors.
The smart phone is mainly used to visualize the readings of the watch and to communicate the alarms.