Miniature Force Sensing System for Monitoring of Optimal Cricoid Pressure for Airway Protection

Application of correct force on cricoid cartilage is an effective approach to prevent the regurgitation of gastric contents. However, the force applied by nurses varies widely, resulting in a proportion of patients remaining at high risk of gastric aspiration due to inadequate force. To guide the nurses to exert consistent and accurate target cricoid force with real time feedback, a flexible, wearable and biocompatible polymer-based force sensor patch was developed, the sensor patch is able to attach on the cricoid cartilage surface. A force read-out system based on printed circuit board was also developed. The light-emitting diodes on the circuit are to indicate the force range. The force sensing system with two sensor patterns (
$3\times 5$
and
$10\times 10$
array) were measured on the flat surface, and curved manikin surface. Human subject was involved in the device experimental calibration and verification. The results show that the surface curvature and testing subject are related to the calibration data and measurement accuracy. The measured force accuracy is within ±2.5 N on the manikin surface, and within ±4.0 N on human subject. As a guided fixture was introduced on the sensor patch, the accuracy of the sensor increased to ±1.5 N.