Soft Capacitive Sensor and Wearable Sleeve Towards Measuring Fluid Retention

Abstract

Measuring fluid retention, or edema, is essential in clinical diagnosis and treatment of disorders. We demonstrate a soft, passively shielded capacitive strain sensor and sleeve worn over the upper arm to detect arm swelling during exercise. In a human subject study, the sensor captured an increase of approximately 7 pF pre- to post-exercise, which corresponded to circumference measurement increase of 0.7 cm. This work has applications to soft and wearable robotic systems for the continuous monitoring of persistent edema with minimal discomfort.