APRV Tlow Timing

Move a point

Touch and drag an endpoint. Holding or dragging opens a magnifier. You can also tap an endpoint, then tap its new position. Drag the line itself to move both ends. Drag empty space to pan; pinch to zoom.

1 · Baseline and rotation

Place both ends on the same zero-flow baseline, left and right. Straightening rotates the image so this line is horizontal. Changing the baseline resets the later calibration and fit.

2 · Time scale

Place A and B on two known time marks and enter their separation in seconds. Horizontal distance determines the time scale.

3 · Peak and decay

Put Peak at peak expiratory flow. Position End so the straight line follows the visible decelerating expiratory-flow envelope through at least the 75% level.

Calculation

The target retains 75% of the peak flow magnitude relative to zero. The interval is found by linear interpolation along the fitted decay line and converted to seconds using the calibrated time axis.

The calculator does not trace the waveform automatically and does not extrapolate beyond the fitted line. Baseline correction rotates the image but does not correct perspective distortion.

Clinical interpretation

This estimates peak-to-75% time only. It does not include any pressure-release-to-peak interval and does not itself prescribe the low-pressure release duration in airway pressure release ventilation (APRV).