Fig. 4

ABBU breath triggering data. A Representative pressure–time scalar (blue) during one porcine experiment. The first five breaths are trigger assisted (blue arrows), followed by a two respiratory cycle pause (green arrow), followed by three control breaths (orange arrows). Mode = Breath means a mechanical breath is being is delivered, Mode = Home means the motor is idle and Paw is below PEEP, Mode = Search is when it calculates PEEP and is searching for a patient effort, and Mode = Trigger means a breath assist is triggered. B Summary of trigger assist algorithm (n = 2). Note that Subject #6 had 22 false negatives (ineffective triggering) attributed to inability of the algorithm to calculate the sensing threshold below PEEP during periods of rapid breathing (50–60 bpm)