A Bench Study of New-Generation Anesthesia Ventilators: Inspiratory Trigger Sensitivity in Pressure-Support Mode

Purpose: The new-generation anesthesia ventilators are better at synchronizing with a patient’s spontaneous respirations, which is important for intensive care. The aim of our study was to evaluate different anesthesia ventilators in pressure-support ventilation mode with regard to aspects of their trigger sensitivity to spontaneous inspiratory breathing.Methods: Four anesthesia machines and one intensive-care ventilator were evaluated. The ventilators were connected to a spontaneously breathing test lung. Each anesthesia machine used a different technology for recognizing the change in gas flow, and different flow generators. The trigger sensitivity, the percentage of triggering failures, and the lag time occurring at the time of an intake of air intake were investigated.Results: The intensive-care ventilator had the highest trigger sensitivity. The trigger sensitivity of the 4 anesthesia machines was also high. The anesthesia machines from most to least sensitive were as follows: machines equipped with a hot-wire flow meter, an ultrasonic flow meter, or a differential pressure-flow meter. In addition, other structural differences between the machines affected the differences in sensitivity.Conclusion: The differences between the trigger sensitivity of the tested anesthesia ventilators were a result of differences in the flow-triggering mechanisms and other structures. Although no anesthesiamachines had higher trigger sensitivity than the intensive-care ventilator, the anesthesia machine most recently on the market had very similar trigger sensitivity