Impact of Respiratory Mechanics and patient's Inspiratory Effort on Flow-Time Scalar Morphology

In volume control mode, the morphology of the flow-time scalar is fixed and unaffected by respiratory system mechanics or Pmus. However, in pressure control mode, a strong Pmus can alter the morphology of the pressure-time scalar. Instead of the normal exponential decay, a sinusoidal waveform may appear in the presence of strong Pmus, and there may be an increase in the peak inspiratory flow. 

The inspiratory limb of the flow-time scalar may reach the baseline early when there is high elasticity (or low compliance) of the respiratory system (because of the short time constant these lung fill or empty early). 

Increased airway resistance is characterized by reduced peak inspiratory flow, a decreased slope of the waveform, and the waveform may fail to reach the baseline before the expiratory phase begins, indicating that these lungs fill slowly due to a long time constant.