The Role of Time in Health IoT

The Role of Time in Health IoT

Lambert Spaanenburg (Comoray AB, Sweden)
Copyright: © 2017 |Pages: 17
DOI: 10.4018/978-1-5225-1820-4.ch007
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As the biological processes in the body change constantly, comparable measurements should be taken simultaneously in time and place. In practice, this is hard to achieve. Synchronicity is required to certify medical accuracy for a new device by reference to a certified one. In a typical health IoT, synchronicity cannot be enforced procedurally and timing needs to be part of the network architecture. Popular examples are in blood pressure measurement. Putting the blood flow in a known pinch-off situation performs synchronization. But this principle cannot be extended to other non-invasive measurements. Hence the chapter proposes to synchronize on basis of the heart rate extracted from the blood flow at arbitrary positions on the body. This models the blood flow in the body and relates all to the rhythm of the heart. It brings existing phenomena into a single, multi-level model that allows wireless networked wearables into a single health-monitoring scheme.
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Blood Flow Analysis

Deep down, the heart drives the blood circulation system. However, its main pipe has a flexible wall and hence behaves non-linearly in response to the applied pressure. The transients in the heartbeat will gradually be smoothed while passing through the artery. Everywhere in the blood circulation system, the heartbeat can be found in a related but gradually different way. Ultimo, some non-invasive measurements at spread-out locations can be used to model an invasive measurement at the heart.

Circulation Diagnosis

Electrocardiogram (ECG) measurements need proper placement of a number of probes. If accurately executed, the signal can be detailed enough allowing more than 250 heart diseases to be detected by the trained nurse. The operation is costly and limited in use to special situations. For the early detection of heart failure, the procedure needs to be cheap and casual.

The heart signal is an intricate set of positive and negative pulses with intermediate planes: the PQRST complex (Figure 1a). It shows the ventricular activity and can be measured as electrical signals. As every peak and every plane has a functional meaning, any aberration has consequences. Though such deviations may be meaningful, they are not appearing often, if ever. Usually a Holter device needs to be carried for one or more days to catch a glimpse of the heart failure. With heart failure being a major cause of sudden death, a cheap and casual detection without special installations is required.

Figure 1.

The (a) PQRST vs. (b) PPG relationship

Source: Al-Qazzaz, 2014.

A healthy body is one in which the heart has no problems to bring blood to all parts of the body. Classical medicine targets the organs, but the body is much more. For instance, an early sign of diabetes is lack of blood flow in the toes. So general health needs to capture both the quality of the heart, usually read from ECG analysis, as well as the service ability of the blood circulation system, potentially found from a distributed Photoplethysmography (PPG) application.

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