Nat Biomed Eng. 2018 Sep;2(9):687-695. doi: 10.1038/s41551-018-0287-x. Epub 2018 Sep 11.

Monitoring of the central blood pressure waveform via a conformal ultrasonic device.

Wang C¹, Li X², Hu H², Zhang L¹, Huang Z¹, Lin M^1,³, Zhang Z¹, Yin Z⁴, Huang B⁵, Gong H¹, Bhaskaran S⁴, Gu Y², Makihata M⁶, Guo Y¹, Lei Y¹, Chen Y¹, Wang C^1,⁷, Li Y¹, Zhang T¹, Chen Z⁸, Pisano AP⁶, Zhang L¹, Zhou Q⁸, Xu S^9,^10,^11,¹².

Author information

1: Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA.
2: Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA.
3: School of Precision Instrument and Optoelectronic Engineering, Tianjin University, Tianjin, China.
4: Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA.
5: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
6: Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA.
7: The Key Laboratory of Materials Processing and Mold of Ministry of Education, School of Materials Science and Engineering, School of Physics & Engineering, Zhengzhou University, Zhengzhou, Henan, China.
8: Department of Ophthalmology and Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA.
9: Department of Nanoengineering, University of California San Diego, La Jolla, CA, USA. shengxu@ucsd.edu.
10: Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA. shengxu@ucsd.edu.
11: Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA. shengxu@ucsd.edu.
12: Department of Bioengineering, University of California San Diego, La Jolla, CA, USA. shengxu@ucsd.edu.

Abstract

Continuous monitoring of the central-blood-pressure waveform from deeply embedded vessels, such as the carotid artery and jugular vein, has clinical value for the prediction of all-cause cardiovascular mortality. However, existing non-invasive approaches, including photoplethysmography and tonometry, only enable access to the superficial peripheral vasculature. Although current ultrasonic technologies allow non-invasive deep-tissue observation, unstable coupling with the tissue surface resulting from the bulkiness and rigidity of conventional ultrasound probes introduces usability constraints. Here, we describe the design and operation of an ultrasonic device that is conformal to the skin and capable of capturing blood-pressure waveforms at deeply embedded arterial and venous sites. The wearable device is ultrathin (240 μm) and stretchable (with strains up to 60%), and enables the non-invasive, continuous and accurate monitoring of cardiovascular events from multiple body locations, which should facilitate its use in a variety of clinical environments.