Novel Ultrathin Miniature Force Sensor to Deliver Optimal Cricoid Pressure for Airway Protection in Patients at High Risk of Gastric Aspiration - a Verification of Design

Cricoid force is applied during airway management to prevent pulmonary aspiration of regurgitated gastric contents. This force is usually applied by a nurse or anaesthesia assistant. Currently this is performed WITHOUT monitoring and the force applied is determined by the individual's "educated hand" that is derived from his/her experience from past training and practice. Studies have shown that the actual force applied by nurse and anaesthesia assistant is inconsistent and deviates from the optimal force. Under application of cricoid force results in ineffective cricoid pressure and the risk of pulmonary aspiration. Consequences of pulmonary aspiration include lung injury and infection, hypoxia, long Intensive Care Unit stay and even death. Over exertion of cricoid force results in distortion of the larynx (leading to difficult bag mask, difficult tracheal tube insertion and hypoxia). Preliminary results from previous study (IRB 2014/437/D), an observation crossover pilot was carried out comparing the amount of cricoid force applied by 16 nurses on manikin with and without direct feedback. Nurses were instructed to apply a range of force of 30-44 Newtons on a marked site on the neck region of manikin. A flexiforce load sensor was used. Unblinded nurses performed significantly better with feedback using the load sensor then blinded nurses. With Funding from a National grant, a real-time measurement of cricoid force is developed to give feedback and guide the operator to exert and maintain the TARGET cricoid pressure during rapid sequence induction (RSI).

In this study we aim to verify the sensor system with a manikin and compare the forces applied by nurses with the sensor system and without.