This project will demonstrate the feasibility of the use of non-contacting acoustic respiratory movement sensor (ARMS) for a device that will be used as a sensor for a module that can trigger any commercially available neonatal ventilator to produce non-invasive synchronized ventilation. Synchronization of the ventilator improves gas exchange, decreases the length of time on invasive ventilation, and probably reduces the development of bronchopulmonary dysplasia. In spite of its advantages, non-invasive synchronized ventilation is not commonly used since there is no commercially available ventilator today that uses accurate synchronization. The main problem with synchronization is the sensor for spontaneous breathing. Our approach to this problem is the development of an acoustic respiratory movement sensor (ARMS) that detects the reflection of a beam of continuous ultrasound off the body surface. The major limitation of the ARMS device is non-respiratory movement which may obscure the respiratory signal. We have developed an algorithm for identifying non-respiratory movements that has been validated by video observation during invasive ventilation in sedated and uncovered infants. In the clinical setting of non-invasive respiratory support, infants are usually non-sedated and covered by blankets. The non-respiratory movement algorithm will be validated by attaching miniature accelerometers to the head, upper arm, and ankle of infants during simultaneous recordings of the ARMS. The inter-method agreement between the ARMS algorithm and the accelerometers will be tested in 12 premature infants in three positions. We will also measure the difference in the response times of the ARMS signal in detecting the onset of inspiration with that of an abdominal pressure capsule that is used in a trigger that was a system for producing non-invasive SIMV (Star Sync, Infrasonic, San Diego, CA) that is no longer commercially available. Using this algorithm, we will assess the amount of non-respiratory movement of 12 additional infants for 12-24 hours. Feasibility of the ARMS will be defined by a failure rate of less than 20% of the time in these recording in which non- respiratory movement obscured the respiratory signal. These recordings will be used in Phase II to produce a hardware prototype of a module for triggering any commercially ventilator for non-invasive SIMV that will be tested for equivalency to the Star Sync for FDA approval and commercialization
The lungs of preterm infants are easily damaged by mechanical ventilation, and synchronizing the ventilator with the infant's owns breathing helps reduce this damage. This project will help create the next generation of mechanical ventilators to further reduce this damage by synchronizing the ventilator so that it can be used non-invasively without a tube in the trachea. The new generation of ventilators will also reduce the amount of effort needed to save the premature infant and save health care costs.
| Heldt, Gregory P; Ward 3rd, Raymond J (2016) Evaluation of Ultrasound-Based Sensor to Monitor Respiratory and Nonrespiratory Movement and Timing in Infants. IEEE Trans Biomed Eng 63:619-29 |
