Soft Robotics Applied to the Development of a Diaphragm Assist System

Abstract

Severe diaphragm dysfunction can lead to respiratory failure, requiring permanent mechanical ventilation. Permanent tethering to a mechanical ventilator via a patient’s mouth or tracheostomy can interfere with a patient’s autonomy by hindering activities like speech and swallowing. This thesis works towards a soft robotic alternative that aims to intervene internally at the diaphragm as opposed to the mouth. For medical problems that are mechanical in nature, soft robotics offer a promising solution by coupling advanced robotic control with soft elements that can interact nondestructively with biological systems. In this work, we present the findings from the development a soft robotic diaphragm assist system, from exploration to proof-of-concept.

In order to understand how soft robotic technologies interact with the respiratory system, simulators of respiratory motion and biomechanics were built with different soft actuator mechanisms. We find that pneumatic artificial muscles are capable of driving the diaphragm function in a respiratory simulator and replicating the work of breathing. Taking inspiration from this biomimetic system, pneumatic artificial muscles are designed and optimized for use in the diaphragm assist system. By implanting contractile, soft robotic actuators above the diaphragm to push down on the diaphragm during inspiration, this diaphragm assist system functions as an implantable ventilator. We demonstrate the proof-of-concept feasibility of this system to augment physiological metrics of ventilation in an in vivo porcine model of varied respiratory insufficiency. This system synchronizes with native respiratory effort to augment respiratory function.

This diaphragm assist system lays the foundational work for a new therapeutic ventilation option that aims to restore respiratory performance without sacrificing quality of life.