Wearable sensors

The healthcare delivery network comprises two distinct supply chains service supply chain and material supply chain. Service supply chain includes healthcare services such as admissions, diagnosis, lab test, surgery, treatment, and recuperation. Material supply chain involves procurement, storage, and deployment of healthcare products - pharmaceuticals, sensors, wearable devices, test equipment, and communication devices. As shown in Fig. 10.2, the materials supply chain includes all the entities, except the employers and the service supply chain excludes drug manufacturers, device manufacturers, and retailers. 

Thanks to advances in miniaturization and developments in sensors and measurement technologies, it is already possible to collect a considerable amount of health-related information from wearable or embedded devices, and numerous new devices are also in the pipeline (Table 32.1). Some of these devices function on a constant basis, whereas others take intermittent mea-... 

M. Shichiri, Y. Yamasaki, N. Hakui, and H. Abe, Wearable artificial endocrine pancreas with needle-type glucose sensor. Lancet 2, 1129-1131 (1982). 

Figure 11. Comparison of a wearable foam sensor integrated into a shirt, and a reference airflow monitor (facemask) for monitoring breathing during treadmill experiments. The results (bottom) indicate that these types of innocuous wearable sensors can provide important information on general heath indicators such as breathing [27].

Schoonen AJ, Schmidt FJ, Hasper H, Verbrugge DA, Tiessen RG, Lerk CF. Development of a potentially wearable glucose sensor for patients with diabetes mellitus design and in-vitro evaluation. Biosensors Bioelectronics 1990, 5, 37 16. 

Aalders AL, Schmidt FJ, Schoonen AJ, Broek IR, Maessen AG, Doorenbos H. Development of a wearable glucose sensor studies in healthy volunteers and in diabetic patients. The International Journal of Artificial Organs 1991, 14, 102-108. 

Schmidt FJ, Aalders AL, Schoonen A JM, Doorenbos H. Calibration of a wearable glucose sensor. International Journal of Artificial Organs 1992, 15, 55-61. 

Kudo H, Sawada T, Kazawa E, Yoshida H, Iwasaki Y, Mitsubayashi K. A flexible and wearable glucose sensor based on functional polymers with Soft-MEMS techniques. Biosensors Bioelectronics 2006, 22, 558-562. 

Healthcare personalized access for individuals, relatives, care givers, and other specialists to real-time or historical information generated by wearable sensors, implantable devices, or home-based diagnostics units will facilitate the movement towards home- or community-based healthcare rather than the current, unsustainable, hospital-centric model in the developed world. In addition, access to low cost communications and diagnostics will also provide a means to rapidly improve the delivery of healthcare in less well-developed regions. 

Research is continuing to develop and refine the sensor design. The TFHS is inherently mgged and inexpensive, making it attractive as a wearable personnel safety device or as a monitoring device for hydrogen fueled vehicles. Further development of the sensor will address the issues and requirements for automotive safety and other applications. 

On the basis of the results from this group, the Roche Diagnostic company has recently produced a wearable apparatus that has been tested in 23 diabetic patients for up to 72 h. The extra-corporeal unit displays a glucose value every minute. The signal is corrected for the time needed for fluid transport from the microdialysis probe to the sensor (31 min). The one-point cahbration mode was used after an initial equflibration time of about 4.7 h. Continuous monitoring was feasible for at least 3 days with no time-dependent dechne in sensitivity to glucose being noted [115]. 

Shichiri, M. Sakakida, M. Nishida, K. Shimoda, S. Enhanced, simplified glucose sensors longterm clinical application of wearable artificial... 

Figure 3, shows one representative case of three days continuous record of an insulin-dependent diabetic treated with continuous subcutaneous insulin infusion. The continuous irronitoring of glucose concentration disclosed a day-by-day variation of gjlycemia in diabetics. Then a large research activity started to miniaturize the system in order to obtain a real wearable artificial pancreas. The first step was miniaturizing the sensor. Today we have on the market several small instruments able to monitor glucose continuously up to one week. ... 

Shichiri M, Kawamori R, Yamasaki T et al. Wearable-type artificial pancreas with needle-type glucose sensor. Lancet 1982 ii l 129-1131. 

Figure 6.18 shows the sensor response to a breathing-like signal. The pressurised air flow is applied and removed according to a natural human breathing rhythm. As shown, despite the hysteresis, the sensor response is reversible, reproducible, and fast enough to monitor physiological parameters in wearable sensor applications. 

Wearable technology consists of wearable electronics, a term that mainly includes simple and more complex electronic devices and their embedding within textile structures. A good example of the popularity of the research subject is the current Qualcomm Tricorder X-Prize competition for the best portable, wireless device that monitors and diagnoses health conditions (XPRIZE, 2014). Undoubtedly, as the aim is that the device monitors such elements as blood pressure, respiratory rate, and temperature, some of the sensors of the device will come in the form of textile-embedded electronics. 

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