Overview
The pleth channel includes a separate respiratory waveform. It replaces crowded inspiration/expiration text and provides a time reference for the pressure variations.
The breathing model changes rate and inspiratory/expiratory duration with oxygenation, shock and selected physiology. Inspiration and expiration therefore need not occupy equal halves of the cycle.
The pressure channels respond to the respiratory model, including the amplified ventricular interaction examples in tamponade and constriction. Ventilatory support changes the respiratory context; the line is a simulated breathing reference, not capnography.