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Figure 1 | Critical Care

Figure 1

From: An automated and standardized neural index to quantify patient-ventilator interaction

Figure 1

Schematic description of the NeuroSync index and graphical display. (A) Time tracing of a schematic electrical activity of the diaphragm (EAdi) signal. Indicators for onset (EAdiON) and termination (EAdiOFF) are presented. Possible range of trigger error (range −100% to 100%, the neural inspiratory detection period) is indicated above the EAdi waveform. Possible range for cycle-off error (−100% to 100%, the neural expiratory detection period) is indicated below the EAdi waveform. (B) Time tracings of schematic ventilator pressure (PV) signals. Six examples of different PV time tracings demonstrate different types of synchronous or dyssynchronous signal (compared to EAdi time tracing in A). (C) Example of signals that are synchronous or dyssynchronous: graphical display. Example 1: a ventilator breath delivered in synchrony with EAdi: EAdiON and start of pressure delivery (PSON) as well as EAdiOFF and end of pressure delivery (PSOFF) occur simultaneously. This event has perfect synchrony (0% error) and is plotted in the center of the graphical display. Example 2: early triggering (PSON occurs at −40% relative to EAdiON) and early cycling-off (PSOFF at −40% relative to EAdiOFF). Events appear outside the box (dyssynchrony) in the lower left quadrant. Example 3: late triggering (PSON occurs at 40% relative to EAdiON) and early cycling-off (PSOFF at −40% relative to EAdiOFF). Events appear outside the box in the upper left quadrant. Example 4: late triggering (PSON occur at 40% relative to EAdiON) and late cycling-off (PSOFF at 40% relative to EAdiOFF). Events appear outside the box in the upper right quadrant. Example 5: early triggering (PSON occur at −40% relative to EAdiON) and late cycling-off (PSOFF at 40% relative to EAdiOFF). Events appear outside the box in the lower right quadrant. Example 6: multiple assist with EAdi (double triggering). First PS assist: early triggering (PSON occurs at −40% relative to EAdiON) and early cycling-off (PSOFF at −40% relative to EAdiOFF), land outside the box in the lower left quadrant (similar to example 2). Second PS assist: late triggering (PSON occurs at 40% relative to EAdiON) and late cycling-off (PSOFF at 40% relative to EAdiOFF) land outside the box in the upper right quadrant (similar to example 4). (D) Example of signals that are asynchronous (that is, 100% error). Example 7 exemplifies assist without EAdi (sometimes known as auto-triggering). Example 8 illustrates EAdi without assist (also known as wasted effort) and multiple EAdi with one assist.

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